Harsh Upshifts (esp. in low gears) / P2716 code (shift solenoid 'D') / Recent OEM Pan Replacement... Thoughts? (2 Viewers)

[Matt Hunoval]

I’m sure Amsoil is fine stuff. I think it’s a good idea to revert back to the condition where it was working originally.
I have seen the problems when other transmission fluid brands were used, and I don’t know if they were/weren’t WS compatible, but there were shifting issues. Those shifting issues were resolved when the fluid was replaced for Toyota WS.

apologies, we may have crossed wires / cross talk. I've done two (2) drop & drains. 1st was 5,500 miles ago and I kept the original pan, AND I used the Amsoil ATF 'Signature Series' (the one labeled ATL on the MSDS sheet, which is specced to be WS compatible) to replace the OEM WS spec fluid in the 1st drop & drain-- and for a drop and drain, that's about 50% of the fluid. And for 5,000 miles it ran like a top with the (ballpark) 50% Amsoil & 50% old OEM WS fluid (which was black and disgusting btw). Actually ran smoother than before the 1st drop & drain & I saw a marginal uptick in MPGs. Upshifts, downshifts, all gears, all speeds. I'm sure just replacing the old ATF with any WS-compatible fluid would have done the same thing after 136k miles! The harsh / jerky upshift issue arose ONLY upon the 2nd drop & drain... 5k miles after the 1st, approx. 500 miles ago. And it was abrupt & sudden and coincided precisely with the 2nd drop & drain and install of the B&M pan. It didn't subtly & slowly start happening, gradually increasing from the 1st drop & drain to the 2nd. 100% of it started happening within a few miles of the 2nd drop and drain. Thus my tentative conclusion / working hypothesis is that the transmission overall isn't shot but, rather, in the process of the 2nd drop and drain and install of the new B&M pan I either a) accidentally knocked some wiring to the solenoids loose or b) with how dirty & old the OEM fluid was, some small particulate matter of caked-on transmission gunk got knocked loose & gummed up the SLT solenoid so that the valve connector is stuck open (thus the p2716 code). As Tom posted, only way I'm gonna find out is to drop the damn thing and troubleshoot the valve body. Will likely go ahead and order a SLT solenoid and new transmission filter for PM reasons & to minimize potential downtime.

 

[Matt Hunoval]

I’m a simple man from the country. Don’t take this the wrong way, but you may have some confirmation bias. I’m still running amsoil atf in mine as I said above. Zero issues.

To confirm: there were no issues before your fluid and pan change, correct? If not, disregard my posts.

If so, something is now not as it was via fluid level or as you said connection, etc being reinstalled incorrectly. Res ipsa loquitur

just noticed the res ipsa loquitur. Nice flare. Need to figure out a way to work in a good infra or supra, maybe try to reference 'International Shoe' while I'm at it. 10 points for you, sir!

 

[gaijin]

The only thing about the pan that truly matters is that the standpipe is in the correct position so that you can adjust the transmission fluid to the proper level. Needs to be done while the transmission is at the correct temperature and the engine is running in park or neutral.

yes; I make sure to do that every time I do a drop & drain 100%.

My simple mind keeps coming back to the possibility that after installation of the deeper pan, you did not refill to the proper fluid level - not enough transmission fluid in the transmission.

Just to check:

- What temperature did you bring the transmission up to?
- Did you lock the transmission thermostat open?

May be nothing, but never hurts to double check, right?

HTH

Edit to add:

I would refer you to the following post for details on transmission fluid replacement procedures according to Toyota:

AT Fluid Replacement Procedure

 

[TomEf]

Open/short in the circuit.

While you have the pan off:
-SLT Solenoid should have 5 to 5.6 ohms between the terminals.
If that tests good then you’ll need to move to testing the connector and harness for an open/short.

It's worth pointing out that solenoids can test good on the bench at room temperature, but have issues at operating temps. I've never actually been able to diagnose a known bad solenoid on the bench at room temp or at operating temp, so your mileage may vary on that.

- Did you lock the transmission thermostat open?

I'm glad you mentioned this, because it's an easy step to miss.





For what it's worth, just last week I did a (basically) complete fluid exchange with the Amsoil ATF. Drained and refilled the pan (didn't drop it), pinned the thermostat, and collected fluid at the exit of the second trans cooler/refilled into the pan. Verified fluid level at the correct temperature per FSM, buttoned it up, and have put almost 1000mi on it since then. No weird shifts, no harshness, no surges when putting it into gear, etc. I can't remember exactly which Amsoil ATF I had, but it did specify it meets/exceeds the Toyota WS requirements.

 

[GrouchyTech]

Here are the testing procedures for your P2716.

 

[Matt Hunoval]

Here are the testing procedures for your P2716.

awesome-- super helpful! Many thanks, sir!

 

[Matt Hunoval]

It's worth pointing out that solenoids can test good on the bench at room temperature, but have issues at operating temps. I've never actually been able to diagnose a known bad solenoid on the bench at room temp or at operating temp, so your mileage may vary on that.




I'm glad you mentioned this, because it's an easy step to miss.





For what it's worth, just last week I did a (basically) complete fluid exchange with the Amsoil ATF. Drained and refilled the pan (didn't drop it), pinned the thermostat, and collected fluid at the exit of the second trans cooler/refilled into the pan. Verified fluid level at the correct temperature per FSM, buttoned it up, and have put almost 1000mi on it since then. No weird shifts, no harshness, no surges when putting it into gear, etc. I can't remember exactly which Amsoil ATF I had, but it did specify it meets/exceeds the Toyota WS requirements.

Good reminder-- will (double)check re: thermostat. Even tho I have a checklist almost like a pilot pre-take off & have replaced ATF fluid 20+ times with other vehicles... it is easy to get to autopilot mode & skip a step.

 

[Matt Hunoval]

My simple mind keeps coming back to the possibility that after installation of the deeper pan, you did not refill to the proper fluid level - not enough transmission fluid in the transmission.

Just to check:

- What temperature did you bring the transmission up to?
- Did you lock the transmission thermostat open?

May be nothing, but never hurts to double check, right?

HTH

Edit to add:

I would refer you to the following post for details on transmission fluid replacement procedures according to Toyota:

AT Fluid Replacement Procedure

temps were 115 degrees, within the specified range. Even though I have an airplane-pilot-like checklist I run thru on maintenance items, didn't think re: the possibility of forgetting to unlock the thermostat. Sometimes one goes on autopilot... so will go check that out!

 

[GrouchyTech]

temps were 115 degrees, within the specified range. Even though I have an airplane-pilot-like checklist I run thru on maintenance items, didn't think re: the possibility of forgetting to unlock the thermostat. Sometimes one goes on autopilot... so will go check that out!

Before you drop the pan to do anything, try just adding another quart and see if the shifting improves. You won't need to drive it far, around the block. If things improve then we need to check the standpipe on that aftermarket pan.

 

[TeCKis300]

Honest Q: here's the technical data sheet on the ATF I used (it is the internal code 'ATL', so look at the 2nd column on page 2): https://www.amsoilcontent.com/ams/lit/databulletins/g3110.pdf

Here's the Toyota WS technical data sheet: https://cdn.website-editor.net/6622da50fd3744b3b1560a41005a6921/files/uploaded/00289-ATFWS.pdf

Which specs, precisely, would indicate the WS is superior? Kinematic Viscosity (stability of fluid over time at two benchmark temps)? Nope. Flash point? Nope. To be fair, however, if you're approaching flash point temps you've got much bigger problems! On every ASTM standard measured, the WS is inferior. No, not by much. At the margins, yes, AMSOIL is a superior ATF across the board.

Don't think you can go wrong either way, but the OEM-is-always-better-no-matter-what isn't really an argument. Tires? The 20-weight oil recommended for U.S. 200 series? Both are OEM.

In taking the OEM-is-always-better line, I'd love to hear a good case for 20-weight oil in the 200 series.

Sorry to hear of the transmission problems. It's not clear there is a specific resolution at this point and it's somewhat of a crapshoot when transmission are throwing codes for solenoids and valve bodies. I'm sure there's a specialty shop out there that may be able to better diagnose and fix, but that component level detail is hard to come by.

Playing devils advocate, this wouldn't be the first time that "compatibility" falls short. How many times have we seen hardware, plug&pray, aftermarket marketing promises fall short. Something meeting specs or standards is only the first step to integration. The reason OEMs spec'd components and fluids always have the advantage is because of extensive testing towards verification and validation. That V&V test, and even V&V of servicing process and methods is critical to the long term success of systems. With anything else, the end user often becomes the tester, the success of which might depend on a body of knowledge from those trying ahead of you. I say this as I've been there too taking hard lessons learned, professionally and in my own hobbies.

That said, I'm not necessarily pointing fingers at the fluid or pan, but they can still be culprits. It could just as much be over-servicing, which has risks itself to creating assembly issues, foreign debris, excess detergent dislodging what would just be normal wear debris, etc.

As an aside, @GrouchyTech is on point with all the great experience and info.

 

[gaijin]

Before you drop the pan to do anything, try just adding another quart and see if the shifting improves. You won't need to drive it far, around the block. If things improve then we need to check the standpipe on that aftermarket pan.

I like that idea!

 

[gaijin]

Bump for any updates from OP @Matt Hunoval ?

 

[Matt Hunoval]

Bump for any updates from OP @Matt Hunoval ?

we're in the middle of a move, and with work, blah blah blah... had to put it on pause for a few days. So apologies for being MIA for the last few days & after re-reading everything, figured that the best 1st step from everyone's collective wisdom / input (thanks!!) was to just add another quart of ATF and drive it a few miles, reset the error codes with my scan tool and see what happens. SIDE NOTE: after starting & letting it idle in hot temps for 10 mins, the harshness was there but less pronounced... lending a bit of evidence for the possibility of fluid level being a tad low (i.e., due to expansion of fluid at higher temps). Of course, my full set of tools and such are in storage who knows where & it'll take a few weeks to sort thru where everything is, so just had the rig up on the driveway ramps (at least I found those!), got the 24mm shallow socket out but used a shorter socket wrench as I couldn't locate my longer one. Couldn't really get the right angle for it (it is a bit of a tight fit) and fought with the fill plug for a few minutes... and of course felt the edges of the fill plug bolt slip & have now rounded the edges of the fill plug bolt. Aaaarrrgh! Didn't strip it, but don't want to risk trying to 'muscle' it and actually stripping the fill plug bolt. There's an independent well-regarded shop up the street that does internal transmission work (have already spoken & sent a detailed email to the service manager), so am going to drop it off in a day or two armed with a helluva lot more knowledge than I had (thanks to all of you guys!) this time last week. Stay tuned...

 

[Matt Hunoval]

Bump for any updates from OP @Matt Hunoval ?

UPDATE: Troubleshooting Round 1. As a reminder, I'm in the middle of a move, so most of my tools, etc., are in boxes who knows where. Synthesizing the collective suggestions (very helpful, thanks all!), figured that I may have done the math wrong when installing the B&M pan (3.5qt extra capacity over OEM) and may be a tad short on fluid. Late last week, located the correct shallow 24mm socket, but not the correct-length socket wrench so that the the socket 'set' correctly on the fill plug. After a few futile turns & seeing I was rounding the edges out on the fill plug, put my tools down and called around to find a nearby independent shop who a) worked on transmission internals and b) didn't just give a knee-jerk 'you need your transmission replaced' answer (it took about 8 calls to 8 different independent shops). Took it in to the 1 shop that substantively engaged & understood what I was describing, stood in the bay while they used the appropriate tools and, while I was about 0.5 qts light, neither I nor the shop owner figured that that kind of a marginal difference (especially with the now-3.5qt extra capacity) was the root cause, but topped it anyhow as Troubleshoot Step 1. Prayed that would do the trick, however.

To the surprise of neither of us, nothing changed.

While I have a good hand-tool bilateral scanner for home-wrenching DIY stuff, I don't have the super-robust scanners that good shops have & so while there with the owner, we ran a scan which drilled down further into the p2176 weeds. The failure of the SLT solenoid per their scanner was electrical-- there was an open circuit / electrical 'loop' not closed going to the SLT solenoid valve.

The shop didn't have time late last week to get into the valve body to determine what, precisely, is going on... but the universe of potential issues appears to have narrowed.

Given the immediacy and suddenness of when the symptoms presented (i.e., immediately after install of the B&M pan) and their narrow scope (only rough shifts in low gear range, really only 1-3, and only while upshifting), COMBINED with the fact that when toggling the ECT controls to 2nd (i.e., starting in 2nd gear), the 2-3 upshift, while noticeable to me & the shop owner... the harshness / jerkiness is quite mild to the point that when my wife is a passenger and I engage the ECT 2nd switch, she thinks the rig is fixed.

As the shop owner himself is the one working on it, it'll be a few days yet... but given the open circuit drill-down of the p2716 code, the working hypothesis is either a) the solenoid crapped out and isn't going to yield the appropriate 5-5.6 ohm reading or b) me being a knucklehead knocked the wiring harness / wiring loose connecting the TCM to the SLT solenoid when installing the B&M pan.

It'll be another day or so before the owner has the time to open the valve body and check the SLT solenoid and wiring to same. For PM reasons, I went ahead and purchased a new SLT solenoid ($200) & am going to have it installed regardless-- to minimize downtime and for peace of mind-- but (fingers crossed) neither of the working theories = a new or rebuilt transmission on the horizon.

So stay tuned for an update in another few days and to all: really, really, really appreciate the input, opinions and experience shared.

While much of what was found / eliminated in the first round of troubleshooting-- and your input-- confirmed that it was highly unlikely that I needed a new / rebuilt transmission nor that the B&M pan being deeper & having a greater capacity vs. the OEM pan as the root cause issue didn't really make sense... you guys helped sharpen my focus so that when I went into the shop, I was a helluva lot more informed and prepared to drill down as narrowly as possible to whatever ends up being the root cause.

Stay tuned my internet friends & brothers-in-arms!

 

[Matt Hunoval]

UPDATE: Troubleshooting Round 1. As a reminder, I'm in the middle of a move, so most of my tools, etc., are in boxes who knows where. Synthesizing the collective suggestions (very helpful, thanks all!), figured that I may have done the math wrong when installing the B&M pan (3.5qt extra capacity over OEM) and may be a tad short on fluid. Late last week, located the correct shallow 24mm socket, but not the correct-length socket wrench so that the the socket 'set' correctly on the fill plug. After a few futile turns & seeing I was rounding the edges out on the fill plug, put my tools down and called around to find a nearby independent shop who a) worked on transmission internals and b) didn't just give a knee-jerk 'you need your transmission replaced' answer (it took about 8 calls to 8 different independent shops). Took it in to the 1 shop that substantively engaged & understood what I was describing, stood in the bay while they used the appropriate tools and, while I was about 0.5 qts light, neither I nor the shop owner figured that that kind of a marginal difference (especially with the now-3.5qt extra capacity) was the root cause, but topped it anyhow as Troubleshoot Step 1. Prayed that would do the trick, however.

To the surprise of neither of us, nothing changed.

While I have a good hand-tool bilateral scanner for home-wrenching DIY stuff, I don't have the super-robust scanners that good shops have & so while there with the owner, we ran a scan which drilled down further into the p2176 weeds. The failure of the SLT solenoid per their scanner was electrical-- there was an open circuit / electrical 'loop' not closed going to the SLT solenoid valve.

The shop didn't have time late last week to get into the valve body to determine what, precisely, is going on... but the universe of potential issues appears to have narrowed.

Given the immediacy and suddenness of when the symptoms presented (i.e., immediately after install of the B&M pan) and their narrow scope (only rough shifts in low gear range, really only 1-3, and only while upshifting), COMBINED with the fact that when toggling the ECT controls to 2nd (i.e., starting in 2nd gear), the 2-3 upshift, while noticeable to me & the shop owner... the harshness / jerkiness is quite mild to the point that when my wife is a passenger and I engage the ECT 2nd switch, she thinks the rig is fixed.

As the shop owner himself is the one working on it, it'll be a few days yet... but given the open circuit drill-down of the p2716 code, the working hypothesis is either a) the solenoid crapped out and isn't going to yield the appropriate 5-5.6 ohm reading or b) me being a knucklehead knocked the wiring harness / wiring loose connecting the TCM to the SLT solenoid when installing the B&M pan.

It'll be another day or so before the owner has the time to open the valve body and check the SLT solenoid and wiring to same. For PM reasons, I went ahead and purchased a new SLT solenoid ($200) & am going to have it installed regardless-- to minimize downtime and for peace of mind-- but (fingers crossed) neither of the working theories = a new or rebuilt transmission on the horizon.

So stay tuned for an update in another few days and to all: really, really, really appreciate the input, opinions and experience shared.

While much of what was found / eliminated in the first round of troubleshooting-- and your input-- confirmed that it was highly unlikely that I needed a new / rebuilt transmission nor that the B&M pan being deeper & having a greater capacity vs. the OEM pan as the root cause issue didn't really make sense... you guys helped sharpen my focus so that when I went into the shop, I was a helluva lot more informed and prepared to drill down as narrowly as possible to whatever ends up being the root cause.

Stay tuned my internet friends & brothers-in-arms!

UPDATE 2. Issue was a crapped out SLT solenoid. Impedance tests revealed a resistance of 6.1 ohms. Not outrageously out of the normal 5-5.6 ohm 'normal' range, but the higher-than-normal-but-not-crazy-high resistance and corresponding open circuit gremlin may help explain why the shifting issues presented were very narrow in scope (lower gear upshifts only, esp. the 1-2 upshift and, to a lesser extent, the 2-3 upshift... but otherwise either not present or not noticable in the 3-4, 4-5 or 5-6 upshift, not any downshift from any gears, no slippage, no hunting for gears, otherwise everything was smooth as silk). The open question is what caused it to crap out in the first place. No way we'll ever know definitively, but my working theory: as the original 2 owners do not appear to have ever changed the OEM ATF fluid nor filter, and I changed it at approx. 135k miles with a drain & fill with the original OEM pan (with Amsoil) as I'm keenly aware to tread carefully and after some number of higher miles X best practices are to do periodic, sequential drain & fills (say at every oil change or every other oil change), then at 140k miles did a 2nd sequential drop & fill (which, again, the rig ran smooth as silk after the 1st change) and, with the install of the new B&M pan with its 3.5 extra quart capacity at 140k miles, that 2nd drop & fill may have introduced too much new ATF within too short a time and some of the old built-up gunk and/or fine particulate matter from 12-year-old OEM AFT fluid with 135k miles on it cleaned up & knocked loose... may have been the cause or contributed to the SLT solenoid's early demise. Again, that's just my idle speculation as to what caused the SLT solenoid to crap out. Might have just suffered premature failure from any number of other reasons... but at least a) I now know what the hell happened and b) I'm not dropping $5k-$10k for a rebuilt/new transmission.

TAKEAWAY / LESSON LEARNED: going forward, with any higher-mileage rig I purchase, if the ATF has never been changed, I'm going to be more conservative in the periods between drain & fills / drop & fills. In this specific instance, for example, it may have been wiser to do the initial drain and fill to get to 50% new ATF & 50% OEM ATF (approx.), then waited (say) until my 2nd or 3rd oil change interval (i.e., 10k-15k miles between vs. 5k miles) prior to doing the drop and drain and install of the new B&M pan. This, of course, presumes my idle speculation re: the root cause. Which we'll never know!

 

[TomEf]

UPDATE 2. Issue was a crapped out SLT solenoid. Impedance tests revealed a resistance of 6.1 ohms. Not outrageously out of the normal 5-5.6 ohm 'normal' range, but the higher-than-normal-but-not-crazy-high resistance and corresponding open circuit gremlin may help explain why the shifting issues presented were very narrow in scope (lower gear upshifts only, esp. the 1-2 upshift and, to a lesser extent, the 2-3 upshift... but otherwise either not present or not noticable in the 3-4, 4-5 or 5-6 upshift, not any downshift from any gears, no slippage, no hunting for gears, otherwise everything was smooth as silk). The open question is what caused it to crap out in the first place.

It's worth pointing out that the resistance may get more and more out of spec at operating temperature. Bench testing at ambient doesn't always reveal an out of spec condition.

I have been hearing more and more solenoid failures in modern non-performance transmissions these days. The Subaru CVTS are notorious, and this isn't the first I've heard of VB solenoids crapping out in the Toyota 6 speeds. I'm not sure if transmissions are generally reliable enough these days that solenoids are the weak link, or maybe solenoid quality has dipped in recent years.

 

[Matt Hunoval]

It's worth pointing out that the resistance may get more and more out of spec at operating temperature. Bench testing at ambient doesn't always reveal an out of spec condition.

I have been hearing more and more solenoid failures in modern non-performance transmissions these days. The Subaru CVTS are notorious, and this isn't the first I've heard of VB solenoids crapping out in the Toyota 6 speeds. I'm not sure if transmissions are generally reliable enough these days that solenoids are the weak link, or maybe solenoid quality has dipped in recent years.

agreed. That's why I went ahead and ordered a new SLT solenoid to install: I had low confidence, if high hopes, that the Troubleshooting Step 1 of topping off the transmission fluid (I was a bit off when I refilled upon installing the new B&M pan-- 0.5 qts light-- still trying to figure out how I screwed that one up) didn't fix anything, which neither I nor the shop owner figured would (0.5 qts short in a now-near-15-qt-capacity closed system ain't ideal, but isn't going to cause catastrophic failure over the course of driving 800 on-road miles). Going in, since I was 99% certain I'd be getting into the valve body anyhow, having a new SLT solenoid on hand to install-- even had the impedance range on the bench test been within the normal range & not the higher 6.1 ohms measured, I was going to go ahead and pop the new one in either way. Additional possible overkill... even though I'd replaced the OEM filter on my 1st drain & fill at now-5,800 miles ago... doing it again now might have been unnecessary, but if my idle speculation about the possibility re: the new ATF fluid with its new & strong detergent blend knocking some of the built-up transmission gunk loose leading / contributing to the SLT solenoid failure... a new filter is cheap insurance since I was already going to be into the valve body anyhow.

Hopefully this will be the end of the voodoo that is a transmission & the endless potential variables that led to my post. Of course will be holding my breath for the next 2k miles or so & will post if anything else unexpected & wonky pops up between now & then.

But, again, sincere thanks to everyone here who provided valuable feedback, experience & wisdom. As iron sharpens iron. Danke all!

 

[TeCKis300]

Awesome that you're chasing this down to the component level. I hope you do find resolution in replacing that part.

There's very little in the hive mind on these details. If you have any pictures and additional detail to share on how to replace this part, that would be awesome for the next guy.

I'm pretty interested in your B&M pan as well. Additional capacity is always a good thing if it doesn't compromise clearance or create too much of an vulnerability offroad? Any insight into how much lower it hangs?

 

[Matt Hunoval]

Awesome that you're chasing this down to the component level. I hope you do find resolution in replacing that part.

There's very little in the hive mind on these details. If you have any pictures and additional detail to share on how to replace this part, that would be awesome for the next guy.

I'm pretty interested in your B&M pan as well. Additional capacity is always a good thing if it doesn't compromise clearance or create too much of an vulnerability offroad? Any insight into how much lower it hangs?

Just playing it forward-- that's the thing I really love about these forums. I have three (3) different rigs: the 2013 LX 570, a 2013 heavily modded JKU & a 2022 Ram Rebel 1500 ecodiesel & there are forums (fora?? lol) for all of them. And folks across the board are incredibly generous with their input / thoughts / wisdom / experience.

99% of the time, someone, at some point, has experienced the issue you're scratching your head about (I'm still trying to figure out the impedance on the speakers in my ML system, for example, as I want to replace the OEM drivers / speakers and-- other than the sub in the boot-- have found almost nada on the impedance of the full speaker array... but that's another thread altogether).

Will address your Qs in reverse order. And I'll need to punt on the forensics of the solenoid D / SLT replacement as I need to get back to my day job, but happy to address your Q on the B&M pan and will post on the other in a few days.

1) The B&M pan. Why I purchased it / Fitment.

First, the reason I purchased it was because of my experience with B&M's pan for my 2022 Ram Rebel 1500 ecodiesel. My transmission operating temps with the OEM pan were in a range of 205-221 degrees. Now they're running at 182-189 degrees. All data-logged over several thousand miles under any/all driving conditions. Additionally, the range / band of variation when at full operating temperatures has been tightened from a 'band' or range of 16 degrees (i.e., 205-221 with the OEM set-up) to 7 degrees.

While obviously the absolute reduction in temps is the more important benefit experienced, and while I don't have a PhD in fluid dynamics, I have a hunch that less variation at full operating temps under all operating conditions is better than greater variation. Even if beneficial only at the margins, the tighter 'band' of temps is an added bonus.

I'd purchased a B&M pan for my 2022 1500 Ram Rebel about 10 months ago at 21k miles on the clock & installed it (came down to the PPE pan or the B&M pan but, for my 1500 truck the B&M pan i) had greater 'extra' fluid capacity than the PPE pan and ii) the PPE pan requires a custom PPE filter, while you can use a OEM filter with the B&M pan).

I'm a bit leery of a complete flush even at that kind of low mileage-- I'm sure it would be fine, but as I did it myself & don't have the requisite equipment in my DIY garage, I did a series of drain & fills over a short time / mileage frame, replacing the OEM fluid with the same Amsoil Signature Series I used recently with my LX 570. No, I'm not an AMSOIL shill nor vendor, but they legit make some of the highest-quality fluids / lubricants / oils, etc. on the market & I've had nothing but great experiences with their products across the vehicles I own. Point of mentioning this is not to get into the dog-chasing-its-tail rabbit hole of arguing over the 'best' oil on the market but, rather, I want to be comprehensive & complete in my answering your Q.

Namely, in addition to installing the B&M pan on my Ram 1500, I also changed the fluid from OEM Mopar to Amsoil as well and that may have also had some impact on the incredible results I experienced, as outlined in the next paragraph. I doubt the specific ATF used had much to do with the dramatically cooler temperatures I now see & that 99.9% of the results came from thje extra capacity & design of the B&M pan, but just wanted to mention this variable to provide as transparent & complete answer to your Q.

PUNCH LINE RESULTS W/ MY RAM TRUCK: Transmission Operating Temps Now 15-30 degrees cooler than OEM w/ 60%+ reduction in temp. 'band.'

Prior to install of the B&M pan, once my Ram got up to full operating temps across any / all driving conditions, with the OEM pan & OEM fluid, the transmission temps would fall in the range of 205-221 degrees (i.e., a 16-degree band), depending on ambient temps, elevation, my payload, etc. These 'OEM temps' were data logged with my scanner over some 15k miles.

In the now-9k miles since I installed the B&M pan on my truck, a sufficient length of time / miles & data points to make an apples-to-apples comparison, the transmission temps now run significantly lower, with a smaller 'range' of temps. I'm now running at 182-189 degrees (i.e., a 7-degree temp variation 'band') as data logged by my scanner over the last 9k miles with the B&M pan. In that time, I've not yet gone over 190 degrees.

To be fair, none of those miles with the OEM pan nor the B&M pan have been in the Rockies towing a 11k trailer-- I'm sure I'd crack 190 easy under that set of conditions.

But, damn, the results spoke for themselves. Best $350 I've spent on an aftermarket part in my life.

RESULTS TO DATE WITH LX 570 & FITMENT: Insufficient Time / Miles / Data Points to Draw Definitive Conclusions (yet); Clearance Cut 1/2" (ish).

As the harsh upshift issues in lower gears started immediately after install of the Toyota 200-series-spec B&M pan, I've driven it sparingly & gingerly (i.e., toggling the '2nd gear' button on the ECT immediately after starting the ignition & prior to engaging the transmission) pending the resolution of the reason for my original post. So I just haven't driven it long enough over enough miles, driving 'normally' to yet begin logging my transmission temps.

Should be getting my rig back tomorrow or Friday, so will report back in 5k miles or so after driving it for sufficient time / miles.

Given the experience I've had with my Ram 1500, I'm fairly confident I'll see a drop in transmission temps at full operating speeds. Maybe not as big of a drop as with my Ram 1500 (the B&M pan for the Ram has a 4.5 extra qt. capacity vs. the 3.5 qts extra for the Toyota / Lexus application), but my expectation is that I'll see the same thing as with my Ram: lower absolute transmission temps & a tighter 'band' of temps.

And of course, while I doubt changing the brand of ATF on my Ram 1500 contributed much to the dramatic results (i.e., because the OEM fluid replaced only had 21k miles on it), I fully expect that the introduction of fresh, new ATF fluid in my 570 replacing the OEM fluid w/ 135k miles will be a contributing factor to whatever results I log. Whether I'd used the Toyota WS or Amsoil or any other WS-spec fluid, the introduction of new ATF fluid replacing the OEM fluid w/ 135k miles is going to have a greater degree of impact on the end results + the B&M pan itself.

It'll be impossible for me to begin to try and quantify what % of the results are attributable to each of the variables changed, but, no matter what I fully expect I'll see a material drop in transmission temps at operating speed under all conditions. Basic physics & fluid dynamics: a greater volume of fluid circulating in a closed system = lower temps. And lower temps= good!

FITMENT: No fitment issues on my Ram 1500 (which has a 1" factory lift & I'm running 295/70/18s on it)-- the dimensions of the pan are such that it 'sits' about 1/2 inches lower than the OEM solution but, as I've got about 10" of clearance already, that 1/2 inch drop doesn't give me any heartburn. And if I'm really going to get into it offroad, I'm taking my 2013 JKU... so other than some light overlanding and using service roads / dirt roads for hunting & fishing, my use case for my Ram truck makes this largely irrelevant.

HOWEVER, on the 570 there are protective cross-members protecting the OEM pan & they fit tight up against the OEM pan. After installing the B&M pan, I couldn't get the cross members back on. And since my SLT solenoid crapped out, I've not had occasion to button things up underneath.

In eyeballing it, however, it won't be a big deal and will be easy to reinstall the cross members with a slight mod-- the crossmembers didn't fit by maybe only 1/2" due to the deeper B&M pan, so I'll just get some washers to use as spacers & may need to get longer bolts to get it re-installed. Easy-peasy.

As I'm not taking my 570 hard-core offroad-- its use case is about the same as my Ram truck in our family-- so the reduction of clearance of 1/2" (ish) doesn't matter to me. But losing around 1/2" inches of clearance may mean a lot to others reading this with a different use case than me & really get into the sh*t offroad and do some serious wheeling, so just FYI for anyone considering the B&M pan.

 

[Matt Hunoval]

For any interested, here is a link to the B&M pan-- as my 570 is black & I tinted the windows all around with 3M Crystalline film at 70% VLT on the windshield (a godsend & is super-helpful in the hot summer months down South maintaining a steady cool interior temperature, reduces glare, etc.), and the next-step-down 3M Ceramic IR series @ 30% VLT on all other windows), things were starting to get a little 'blacked out' for my personal taste & so to add a subtle touch of personality, I've added red aftermarket recovery points up front from Slee & then spray painted the exterior of the B&M pan with fire-engine red brake caliper paint. Anyhow, for anyone interested here is the link to that B&M pan:

https://www.holley.com/products/drivetrain/transmission_pans_and_accessories/toyota/parts/70393

It is sold by other online outlets as well, so if you're going to pull the trigger shop around a little to get the best price.