Alert, Alert, Alert----- Transmission valve body wire housing block! --- Have you looked into yours? Capillary action drawing ATF in!

[Unrulykid]

I didn’t know I had a problem, but this issue is certainly developing on my 112,000 mile 2002 LX.
Disappointed. But very glad it was revealed.

Seems that the latest revision of this transmission wire harness (for 2002 LX470 with 4 speed A343f transmission) is Toyota Part # 82125-60383. Just looked it up on the Toyota site.

Strange thing is that the Toyota online no longer shows previous part numbers. And Lexus online shows that part # 82125-60383 does not fit my vehicle. Lexus says part # 8212560381. Although the Toyota site shows this part is # 8212560383. Partsouq And @2001LC shows part # 8212560382.

@2001LC- can you give me some insight as to the correct and latest part number for this application? I’d like to order before the 25% sale expires in 4 days. I believe that the part numbers discussed previously are for the external transmission wire harness… This part on my vehicle has not been damaged.
I need the male wire connector and internal wiring harness. I believe this is Toyota part # 82125-60310 for the male electrical connector mounted on the exterior of the transmission housing, and the wiring that runs to the inside of the transmission.

Toyota Parts Center Online 25% off sale with no tax and free shipping to California, price is $148.51 for part # 8212560383.

IMPEX Japan is $130 including shipping, plus unknown tariff amount. And, wait 6 weeks to get the parts.

As I said before, this ATF wicking has not presented any functional issues for this vehicle, but I think I’ve caught it early, as the ATF has only made it’s way into the bottom of the male connector mounted on the outside of the transmission. Female connector shows no signs of ATF at all. And I don’t wanna wait and find out what could happen next if I don’t do anything about it.

As soon as I clarify the correct and current part number, I’ll order (Toyota part # 82125-60310) the external male connector and wiring for inside the transmission from Toyota as PM.

Thanks to 2001LC for posting about this issue.

 

[2001LC]

I didn’t know I had a problem, but this issue is certainly developing on my 112,000 mile 2002 LX.
Disappointed. But very glad it was revealed.

Seems that the latest revision of this transmission wire harness (for 2002 LX470 with 4 speed A343f transmission) is Toyota Part # 82125-60383. Just looked it up on the Toyota site.

Strange thing is that the Toyota online no longer shows previous part numbers. And Lexus online shows that part # 82125-60383 does not fit my vehicle. Lexus says part # 8212560381. Although the Toyota site shows this part is # 8212560383. Partsouq And @2001LC shows part # 8212560382.

@2001LC- can you give me some insight as to the correct and latest part number for this application? I’d like to order before the 25% sale expires in 4 days. I believe that the part numbers discussed previously are for the external transmission wire harness… This part on my vehicle has not been damaged.
I need the male wire connector and internal wiring harness. I believe this is Toyota part # 82125-60310 for the male electrical connector mounted on the exterior of the transmission housing, and the wiring that runs to the inside of the transmission.

Toyota Parts Center Online 25% off sale with no tax and free shipping to California, price is $148.51 for part # 8212560383.

IMPEX Japan is $130 including shipping, plus unknown tariff amount. And, wait 6 weeks to get the parts.

As I said before, this ATF wicking has not presented any functional issues for this vehicle, but I think I’ve caught it early, as the ATF has only made it’s way into the male connector mounted on the outside of the transmission. Female connector shows no signs of ATF at all. And I don’t wanna wait and find out what could happen next if I don’t do anything about it.

As soon as I clarify the correct and current part number, I’ll order the external male connector and wiring for inside the transmission from Toyota as PM.

Thanks to 2001LC for posting about this issue.

Keep in mind, I'm not a parts man or source for P/N's. I buy from them and build relationship with them at Dealerships.

As a general rule, I do not give out parts numbers. WHY: For one we've so many variation around the world of 100 series. Additionally, Year and Model make a difference. Sometimes we've changes within same year. Some of those changes, like 2000 brake master, new P/N does not replace old. But most P/N do roll-up to newest.

The 1998-2002LX/LC is A343f ,commonly referred as 3 spd., or 3spd w/OD. I've a 2002LX with 09-2003 manufacture date VIN, I used at PQ: I see the Main Transmission wire harness (octopus of wires, that wraps outside of A/T case) as P/N 82125-09382 02.2002-08.2002
original 82125-60380 01.1998-02.2002. So very likely 82125-09382 is good for all USA 98-02LC/LX

We order original P/N and input VIN, during check out. The Toyota or Lexus system, insure correct part or the dealership makes it right (replace parts and pays shipping) when VIN used. Unfortunately, Lexus VIIN won't "usually" work at a Toyota Dealership or vis versa.

I suggest you call a Lexus Dealer Today or Monday. Confirm with your VIN. that the 82125-09382 Main wire harness. Is correct for your VIN.

Looking at your picture of transmission wire 82125-60310. The wire harness that goes into case and attaches to solenoids and temperature sensor. I do see what's may be some liquid in bottom. It's a very tough call, with your picture or video resolution. I've a few ways to take pictures. One is my iphone with flash on. Or other, my direction borescope. I did above with borescope. But it should be possible to hold iphone above with flash on. To get clear picture. It will be interesting to see pic when you get out.

BTW: I case you did not know. All A343f I've seen, that pan has never been off. Do not have a gasket. Factory sealed pan with FIPG. Breaking the FIPG bond, is often challenging.

 

[2001LC]

I should add if your transmission wire 82125-60310 (wire housing block & harness, into A/T case). Does have fluid from capillary action drawing ATF from A/T case. It will be the first in this thread, document. I've not yet found pictures elsewhere, of the A343f with this issue. But I've been focused on the A750f, as have been my online searches.

 

[2001LC]

Place holder 1

 

[2001LC]

Place holder 2

 

[Unrulykid]

Keep in mind, I'm not a parts man or source for P/N's. I buy from them and build relationship with them at Dealerships.

As a general rule, I do not give out parts numbers. WHY: For one we've so many variation around the world of 100 series. Additionally, Year and Model make a difference. Sometimes we've changes within same year. Some of those changes, like 2000 brake master, new P/N does not replace old. But most P/N do roll-up to newest.

The 1998-2002LX/LC is A343f ,commonly referred as 3 spd., or 3spd w/OD. I've a 2002LX with 09-2003 manufacture date VIN, I used at PQ: I see the Main Transmission wire harness (octopus of wires, that wraps outside of A/T case) as P/N 82125-09382 02.2002-08.2002
original 82125-60380 01.1998-02.2002. So very likely 82125-09382 is good for all USA 98-02LC/LX

We order original P/N and input VIN, during check out. The Toyota or Lexus system, insure correct part or the dealership makes it right (replace parts and pays shipping) when VIN used. Unfortunately, Lexus VIIN won't "usually" work at a Toyota Dealership or vis versa.

I suggest you call a Lexus Dealer Today or Monday. Confirm with your VIN. that the 82125-09382 Main wire harness. Is correct for your VIN.

Looking at your picture of transmission wire 82125-60310. The wire harness that goes into case and attaches to solenoids and temperature sensor. I do see what's may be some liquid in bottom. It's a very tough call, with your picture or video resolution. I've a few ways to take pictures. One is my iphone with flash on. Or other, my direction borescope. I did above with borescope. But it should be possible to hold iphone above with flash on. To get clear picture. It will be interesting to see pic when you get out.

BTW: I case you did not know. All A343f I've seen, that pan has never been off. Do not have a gasket. Factory sealed pan with FIPG. Breaking the FIPG bond, is often challenging.

I can fully appreciate your reservation to giving out part numbers, and I completely understand the reasons why.
I input my VIN number to the Lexus parts website, and confirmed the transmission wire part number.
The Toyota parts website would not accept my VIN number, because it’s an LX.

On my vehicle, transmission wire # 82125-60310 does indeed have a small amount of ATF down in the bottom of the connector. I understand it’s difficult to tell exactly what it is from the low resolution video that I posted. The combination of a 10-year-old inexpensive borescope, translated to video by filming it with an iPhone does not do it justice… due to the tight confines of the male connector bolted to the transmission body,I cut the fluffy end off of a Q-tip and poked the stick part down into the fluid at the bottom of the connector. It is definitely ATF in the bottom of the male connector…

And you are absolutely correct, removing the transmission pan and the cleaning involved is going to be monotonous and challenging. FIPG is tough and tenacious… But I’ve done it before on other Toyotas, as well as at least a dozen times on a handful of different makes and models. Not looking forward to the removal, but it needs to be done so that the ATF wicking issue does not present into greater and more costly problems.

If this ends up being the first reported case for an A343f transmission, that’s OK… I am just trying to report what I find. And I believe I have found this issue before any functionality issues with transmission operation have presented. Perhaps there are more that simply have not discovered this ATF wicking issue because their transmissions have not displayed any problems. It’s pretty simple to check. Unplug the connector and look inside.

I would never have suspected my vehicle to be affected, but I’m glad that I caught it early. I would not even have looked into this connector, but I read your post and thought I would try to get you some photos as a reference. And, son of a bitch… I was very surprised by what I found.

Thanks again, for noticing the trend and for posting about this issue.

 

[2001LC]

On my vehicle, transmission wire # 82125-60310 does indeed have a small amount of ATF down in the bottom of the connector. I understand it’s difficult to tell exactly what it is from the low resolution video that I posted. The combination of a 10-year-old inexpensive borescope, translated to video by filming it with an iPhone does not do it justice… due to the tight confines of the male connector bolted to the transmission body,I cut the fluffy end off of a Q-tip and poked the stick part down into the fluid at the bottom of the connector. It is definitely ATF in the bottom of the male connector…

Based on your findings: It does appear the 1998-2002 A343f. Will also need their, transmission case wire, inspected as a PM.

Interesting 1998-2002, Toyota, did not change from original P/N 82125-60310 (A/T case to valve body) wire harness, that I've seen. Doesn't mean harness didn't have a modification. But is less likely

It becomes even more convoluted. In that we've, 5 Part numbers, for the A750f:
2003-- LX/LC. 82125-60550 original and is only one listed. Which was first year of the 5spd A750f, last year we have A/T dipstick and only year to use Toy IV ATF.
2004 & 05LC/LX 82125-35130 original and is only one listed. Year dipstick removed an first year of Toy WS ATF.
2006 & 07LC/LC 82125-60651 latest version, 82125-35150 was original, which was first replaced 82125-60650.

Just because we see new P/N. Doesn't mean they correct some issue or defect. Nor does original P/N mean they didn't redesign.
The only time we know for sure P/N means a defect correct. Is when Toyota issues a TSB.

Bottom line:

1. Will need to come up with PM schedule. For inspecting A/T case harness. Perhaps 10 yr or 150K miles, 5 yr 50K thereafter.
2. Also being vigilant, at watching for any contamination (oil, grease, dirt or oxidation) in wire housing blocks.
3. Note DTC, like those of A/T and O2 and perhaps more that this thread yields clues to. That may be related. Double check wire harness(s) first.

 

[Rednexus]

My personal suggestion (for an A750F anyway) would be to replace the harness if 1) there is any strange trans behavior at all or 2) proactively replace it between 150-200K. It's a cheap enough and easy enough job to do, especially if it's lumped in with a fluid exchange. The harness costs less than 15 quarts of new fluid.

 

[2001LC]

My personal suggestion (for an A750F anyway) would be to replace the harness if 1) there is any strange trans behavior at all or 2) proactively replace it between 150-200K. It's a cheap enough and easy enough job to do, especially if it's lumped in with a fluid exchange. The harness costs less than 15 quarts of new fluid.
View attachment 4039415

Good advise!

 

[Trunk Monkey]

While this is potentially causing everyone concern to check their wiring harness and order new ones, it should be pointed out, that how often this occurs is unknown and reported issues or problems where this is the cause is also unknown.

 

[2001LC]

While this is potentially causing everyone concern to check their wiring harness and order new ones, it should be pointed out, that how often this occurs is unknown and reported issues or problems where this is the cause is also unknown.

Good point, TM.

Nobody needs to runout and buy these, wire harnesses! Even if, they find grease in wire housing block.

At this point. This is a Exploratory Fact Finding Alert. Which I edited heading to alert (perhaps unjustly) just last night.

Point of Thread:

1. Get people looking.
2. Post pictures of their wire harness housing block. So we can see what's normal and what's not.
3. Report if any issues or not, that may be associated. To help with diagnostic work.
4. If wire harness R&R. Was in respond to issue(s). If so, did issues, if any, clear-up.
5. See if this needs be in our Preventive Maintenance (PM), scheduled. Or do we just wait for symptom(s) and what are those.
6. See if Toyota change in wire harness P/N. Is actually change in how manufacture, in response to issue (capillary action). If so, is change effective.
7. Find if Toyota was adding some sort of grease to Transmission Wire Housing Block(s)and or within or wires sheathing themselves and why!

In the over 27 to 18 (1998-2007) years of the North American 100 series. Report incidence of contaminations and it being associated with issue, had been nearly nonexistence.

@Unrulykid 2002 LX w/122K. Showed grease in the male (main A/T harness) side. Grease look clean and purposeful placed there. He (2nd owner), was relatively sure, his harness, had NOT been touch since factory installed. But that is subject, based on service history of PO. He had ZERO issues.

So is it normal to find grease, in these wire harnesses or housing blocks (plugs):

• Did factory pack grease in wire housing block. Perhaps as a plug, to stop migration of ATF capillary action.
• Was grease pack in wires inside sheathing, then migrated into wire housing block.
• Was grease add by someone, after factory build date.

Beneficial or non event of, grease or oil, in/on wire connection.
Typically we think of oil or certain types of grease, on wire contacts or in wire housing blocks. As beneficial/protective, to wire connections or non event. Few examples of benefits or non event:

1. White-Lithium grease on battery post, mitigates oxidation. Should be noted: Toyota advises against, use of any grease on post or clamps of battery.
2. Dielectric grease found in some wire housing block. That, appears factory placed there. Which I've presumed as moisture block.
3. The 5.7L 3UR (200 series). 1 in 1000 oil leak issues, from base of spark plug tube. Resulting spark plug tubes fill with oil. Toyota calls a non event, not effecting spark.

 

[Rednexus]

For my P2759 issue, it was much more work to diagnose the harness problem than it was to R&R the harness. I checked resistance across the TCC solenoid at the ECM plug behind the dash, at my WAT lockup switch module, at the plug on the exterior of the trans (which required buying a Doorman chassis-side trans plug pigtail), and across the solenoid itself. Actual harness replacement was a simple R&R. If a P2759 is thrown, the TCC lockup won't engage, which can cause your trans to get hot. It's not a code you'd want to have thrown on a long trip, as it could cook your transmission and would be hard for a non-Toyota mechanic to properly diagnose.

While I'm not recommending everyone to go out and replace this right away, I see no reason to not replace this $58 harness as part of a scheduled/routine trans service for a 15+ year old, high-mileage, A750F-equipped Toyota. After all, we shouldn't expect wire sheathing and connections to last forever when they are bathed constantly in hot transmission fluid. Luckily, the 8212560651 harness was used in the USA through 2023 in the 4Runner, so Toyota should produce it for many years to come.

 

[2001LC]

For my P2759 issue, it was much more work to diagnose the harness problem than it was to R&R the harness. I checked resistance across the TCC solenoid at the ECM plug behind the dash, at my WAT lockup switch module, at the plug on the exterior of the trans (which required buying a Doorman chassis-side trans plug pigtail), and across the solenoid itself. Actual harness replacement was a simple R&R. If a P2759 is thrown, the TCC lockup won't engage, which can cause your trans to get hot. It's not a code you'd want to have thrown on a long trip, as it could cook your transmission and would be hard for a non-Toyota mechanic to properly diagnose.

While I'm not recommending everyone to go out and replace this right away, I see no reason to not replace this $58 harness as part of a scheduled/routine trans service for a 15+ year old, high-mileage, A750F-equipped Toyota. After all, we shouldn't expect wire sheathing and connections to last forever when they are bathed constantly in hot transmission fluid. Luckily, the 8212560651 harness was used in the USA through 2023 in the 4Runner, so Toyota should produce it for many years to come.

I replaced the transmission-side of the harness in my 2007 GX470 (part number 8212560651). The part is readily available from Toyota for around $60. It didn't have any obvious wicking issues, but I was getting P2759 codes and wanted to eliminate every variable. The transmission started shifting quite a bit better after replacing the harness (it had a weird "hop" in the shifts that went away), so it's totally possible the harness was degraded with increased resistance even if no fluid was in the connector. And, the P2759 code went away. So my recommendation is to replace the harness if one is having any issues on a higher-mileage/older A750F.

The harness part has been updated by Toyota (at least since 2007) and wasn't an exact match to the original, so it can be easy to hook up the solenoids wrong. Good photographs of the old harness - before you remove it - are recommended.

Can you describe the transmission weird "hope" ? Was like a delay the bang into grease, or? Any other DTC's or symptoms?

 

[Rednexus]

Can you describe the transmission weird "hope" ? Was like a delay the bang into grease, or? Any other DTC's or symptoms?

Hard to describe. Instead of the upshifts being direct (one gear to another), it was like the 1-2 and 2-3 shifts in particular were delayed somewhat with the trans going part way into gear, then all of the way into gear. I had no other codes beyond the P2759. My trans is also not stock as I have a WAT lockup module and a Nomad Stage 1 valve body in it. With a stock A750F (which shifts very slow/sloppy IMO), you might not even notice that behavior. My assumption at this time was that my trans was getting worn out. Now it shifts perfect again (nice and firm), despite having 199K on it.

I'm speculating that the WAT lockup module contributing to triggering of the P2759 code (which is based on the resistance across the TCC solenoid being higher than Toyota's spec). The lockup module splices into the the TCC lockup wiring, and must have added a few tenths of a ohm of resistance to the TCC solenoid circuit (enough to trigger a code if the harness resistance was already near the upper end of Toyota's spec). However I did check resistance across the module and basically all other wiring to rule things out - and determined the highest resistance was across the trans harness, which is why I replaced it.

I ran the WAT module for 2 years before I got a P2759 code, which to me indicates the harness degraded over this time (increasing in resistance) until it finally the code was triggered. My shifts with the Nomad valve body were also very good when it was installed, and didn't get weird for about a year. So, I'm also speculating that the resistance in the harness must have been high for all other solenoids (but not high enough to trigger a code), and the improved voltage going to the solenoids must have improved shift performance. After all I don't think we could expect the solenoids to function perfectly if they aren't getting full voltage due to a degraded harness.

 

[Rednexus]

Can you describe the transmission weird "hope" ? Was like a delay the bang into grease, or? Any other DTC's or symptoms?

Also, if someone wanted to check harness condition without dropping the pan they could use the Dorman pigtail, plug it into the side of the trans, and then check resistance across each solenoid and compare it to the Toyota spec. This would be an easy job with the vehicle on a lift, but was a bit harder for me with the vehicle on jackstands. If any of the resistances are near the upper end of Toyota's spec, this would indicate the harness is becoming degraded, and it could be replaced. I would also suggest checking the resistance across each solenoid when the harness is replaced to make sure they are fine (I didn't do that as I was focused on the P2759 code). But, my experience certainly suggests the entire harness was degraded and affecting the performance of multiple solenoids.

 

[2001LC]

Also, if someone wanted to check harness condition without dropping the pan they could use the Dorman pigtail, plug it into the side of the trans, and then check resistance across each solenoid and compare it to the Toyota spec. This would be an easy job with the vehicle on a lift, but was a bit harder for me with the vehicle on jackstands. If any of the resistances are near the upper end of Toyota's spec, this would indicate the harness is becoming degraded, and it could be replaced. I would also suggest checking the resistance across each solenoid when the harness is replaced to make sure they are fine (I didn't do that as I was focused on the P2759 code). But, my experience certainly suggests the entire harness was degraded and affecting the performance of multiple solenoids.

Good advise!

I place that Dorman harness in my Amazon cart, after seeing your earlier post. Checking OMH without, with harness bolted down in case, isn't really doable.

Another way to get clues, as to if a shifting issue is: electrical or mechanical. Unplug the main harness wire housing block from the one bolt to the case. Drive shifting manually. A750f D to 4 no RPM change, nor or shift will be felt. A343f OD button OFF / ON, no effect. But all other gears should work as normal/shift. Is clue, shift issue is electrical (wire harness or solenoids), rather than mechanical. Then attach Dorman wire housing block, and isolated more.
See PDF attached.

Let me ask you @Rednexus Do you know or have any clues as to, if:

1. Any TSB out on this Transmissions wire?
2. Did Toyota use at the factory, any grease/gel/etc. in either male or female end of these wire housing block(s)?
3. Did Toyota use any grease/gel/etc., inside wire harness?
4. Was revised part (P/N) for transmission wire, attempt to correct capillary action and did it?

 

[OwnerCS]

Is it possibly, ATF or some sort dielectric grease (DG) or mix looks like this GOO. If just ATF color seems wrong and looks to thick. If just DG, should be thicker at 60F. So mix perhaps
Anyone seen, a color and consistence like this oily looking substance?
View attachment 4036501
If we don't get ahead of this. We could end up with, very costly repair bills.

We've not seen many 100 series, with automatic transmission (A/T) issue. But same A/T A750 is in many makes and model, which are seeing issues: Shifting, A/T valve body and O2 issues. We may find the root cause. Began with electric short in wire housing. So as 100 series fleet ages. We'll likely see the same!

Where I'm I going with this thread:

1. Alert and Recommend a PM.

We need to:

• Identify original P/N, that can in vehicle and it's issue.
• Identify any replacement harness "P/N" that fix or subsequent had issue.
• Which years, makes and models.
• Use info to know what to look for in which years with which wire harness. i.e. Goo, ATF, oxidation or corrosion in wires and or wire housing block(s).
• Identify further down and upstream issues and damage. Caused by defect wire harness.
• Identify and correct design defect, of wire harness(s).

To help guide us. We need info from outside the 100 series community, also. Seems other makes and models with A750 & 760, are seeing issues before us.

Looks like Fluid Film. Does it smell like a sheep?

 

[Rednexus]

Let me ask you @Rednexus Do you know or have any clues as to, if:

1. Any TSB out on this Transmissions wire?
2. Did Toyota use at the factory, any grease/gel/etc. in either male or female end of these wire housing block(s)?
3. Did Toyota use any grease/gel/etc., inside wire harness?
4. Was revised part (P/N) for transmission wire, attempt to correct capillary action and did it?

1. I'm not aware of any TSBs on this, but I haven't checked either. I used a 2005 GX470 FSM to diagnose the issue.
2. I don't recall seeing any grease/gel/etc. in this or any other connectors on my GX470, and I recall it being somewhat hard to remove.
3. See above - I haven't seen any gel anywhere.
4. Not sure on the reason for the revised part number. But, I can confirm the wire colors are different in the new one than they were in my 2007 GX470. It made it harder to re-install the harness, and it would be easy to hook up the solenoids wrong. Some of the routing might have also been different. It was most definitely NOT the exact same part as what came out of my GX.

My situation is unique as likely the only reason I ever threw a code was due to my lockup switch. Otherwise, I would have drove around for indefinitely with a sloppy-shifting transmission, and blamed it on the age/mileage of the clutches and solenoids .

 

[fjc-man]

This statement doesn’t resolve anything and I don’t remember if there was a “fix” for this weird siphoning action. But…when I was a tech with Mercedes in Colorado (the last 4 of 30yrs with Benz) 2000 - 2004 we had cases of capillary action. The atf would flood the transmission ecu.

 

[duowing]

This is not related to the the transmission, but I think the 2UZ VVTI uses the same cam position sensors mounted to the the side of the head in between each bank of injectors. On the 3UZ in my LS I had found oil in the connectors of those sensors and it was beginning to work it's way into the pins of the harness. Another point that 100 series VVTi owners might want to look into.