Torque Converter Lock-up mods any BTDT

[SUMOTOY]

Torque Converter Lock-up Mods to the A442F 80 Series Trans

Has anyone tried to modifiy the signal to the torque converter lockup solenoid? I found one reference to this with a guy in AUS, that has lower TcFD gears and a torque converter lock-up switch, but neither appears installed.

Looking at the new FJ Flex Lockup Torque Converter and other marques newer truck "downhill descent mode" vs the factory FSM on the 442, this sure appears to be a modification that might be beneficial during downhill descents and possibly rock crawling. 1st gear has no lockup function in the factory 80 trans ECU, which means maximum slippage (heat) of the Torque Converter during downhill approaches. It appears that the modification signal to the TCLO solenoid is fairly straight forward.

The stock 80 currently unlocks the torque converter if any of the three conditions are present: CC drops below 2mph from set speed, IDL switch activation on T-body, or brake light switch activated. Sure seems to me that if you left the brake signal disengage to prevent engine stall, you would have direct drive (engine>gears) lockup torque converter for hill descents. On throttle appears to be a bit trickier, but the signal values in the FSM could give partial lockup lockup conditions for climbing based on varying load parameters. Just like the new FJ, hopefully just simpler and less problematic.

Anyone tried a lockup switch on the torque converter?

Scott J
93 FZJ80 Supercharged

 

[Toyo Boyo]

Anyone tried a lockup switch on the torque converter?

Scott J
93 FZJ80 Supercharged

Hi Scott,

A mate of mine has done this to his Hilux Surf, A340 transmission.

I have been in the truck and it works really well. Just a small flick switch in cab to force the lock up. He was working out an more sophisticated system to make sure he couldn't damage the tranny under certain conditions.

I will find his write up and post a link.

EDIT

http://www.hiluxsurf.co.uk/forums/showthread.php?t=47915

http://www.hiluxsurf.co.uk/forums/showthread.php?t=47892

Maybe of some use to you????

 

[Tools R Us]

I looked into it a couple of years ago. IIRC valve body modification is necessary to make it happen? It's one of those things that looks good on paper may or may not work well on the trail? My biggest concern is durability it's designed to work in pretty much steady state cruising, so how would it handle the much higher torque/impact loads on the trail, especially in low range? My guess is that it's not designed for that type of abuse.

 

[Tools R Us]

IIRC Rodney sells a lockup kit?

 

[SUMOTOY]

Hi Scott,
A mate of mine has done this to his Hilux Surf, A340 transmission.
I have been in the truck and it works really well. Just a small flick switch in cab to force the lock up. He was working out an more sophisticated system to make sure he couldn't damage the tranny under certain conditions.

Thanks for the links Andrew, and I see you posting into them early on. Figgrs. I would think this would need to be either momentary contact switch, or retain brake override, which could present possibe marginal benefit during left foot brake applied torque (+Teng) crawling/wheeling.

I see the potential for a very sophisticated system as the factory TC in the 442 has 8 unique lockup settings for lockup built into the factory Trans ECU. To start the benefits, I would think just a simple on off circuit with applied voltage thru the test connector would work.

I looked into it a couple of years ago. IIRC valve body modification is necessary to make it happen? It's one of those things that looks good on paper may or may not work well on the trail? My biggest concern is durability it's designed to work in pretty much steady state cruising, so how would it handle the much higher torque/impact loads on the trail, especially in low range? My guess is that it's not designed for that type of abuse.

I have the circuit (Sumo LUTC Mod?) almost completely designed to the FSM Trans ecu wiring, and I see no reason at all to modify the valve circuit, my understanding of the 442 - Torque Converter lockup isn't a function of the valve circuit it's the function of the lockup solenoid that controls the valve circuit. Working on the trail? No idea, that's why I asked. I see awesome potential for this as a downhill (descent mode) mod with a brake switch disengage override to prevent stall. I guess I could see possible issues on climbing, but I see more good than bad, you effectively lower the stall speed of the TC, during crawling I see nothing but good things from that. Toyota factory stall speed of the 442 trans TC is 2150 +/- 150. As many have indicated in the gearing posts, during crawling you might never see those rpm's. Then that's a lot of trans heat to shed at low rpm. And never a direct engine>gearing connection going downhill.

Side benefits? Much lower transmission temps. Less wear on transmission. Direct drive of gearing during climb and hill descents.

I'll read thru Andrews links and see what the downside are. I don't agree with the summary "not designed for that type of abuse". I claim the torque converter isn't factory designed to take "that type of abuse" of crawling and long descents. Done correctly for offroad, this mod will increase the life of the trans and TC, not decrease it. Looking on Mud's FJ forum, it would appear Toyota is having problems with the mixed driving application Flex Lockup torque converter, and I bet that has to be really tough to get right as a DD, trans fluid temp variables in mixed driving could make that a tough software app. But the concept for downhill crawl is part and partial to "downhill" offroad modes in new trucks.

Scott J
94 FZJ80 Supercharged

 

[SUMOTOY]

IIRC Rodney sells a lockup kit?

Wildsmith appears to have installed that. I still see no reason for valve body mods, it may make shifts more firm, but that appears to *also* be a function of Trans ECU voltage, not just valve spring pressure. Firmer shifts are made by pushing the "power" mode on the dash, that's just modifying the solenoid voltages.

https://forum.ih8mud.com/80-series-...t-noob-question-manual-trans-lockup-auto.html

<Edit> The valve body mod itself doesn't appear this is a first or second gear mod, this is for modification to the higher stresses of towing etc 3rd and 4th gear lockup on the street.... The switch and relay can be used in any gear according to Wildsmith's feedback.

http://www.automatictransmission.com.au/release.asp?NewsId=11360

Scott J

 

[Tools R Us]

Hi I have an A343F transmission in a V6 Prado. For steep descents I wanted to make an override to manually lock the Torque converter to improve engine braking & control. Controlling the TCC from SL (blue wire) terminal on the ECU, I have found that the TCC will manually lock in every gear except first which is obviously where it is needed. It won't lock in 1st regardless of where the tranmission selector is. I haven't tried tracing it back to the transmission to see if there is any control mechanism between the ECU & transmission which may disable TCC lock in 1st. Is this because of hydraulic valving, or do I need to trace the wiring? Thanks Phil

You would need to fit one of our Extreme Recalibrated Valve Bodies to over come this problem. There is a 1st and reverse gear override that stops the loc-up from working. All of our Extreme valve bodies have this feature removed regardless of if they are fitting a relay lock-up or not. You can't just hard wire the lock-up either as you will burn the transmission out if the loc-up is left Off for to long. We sell a relay manual lock-up kit that solves this problem.

From;
Wholesale Automatic Transmissions

 

[Tools R Us]

Wholesale Automatic Transmissions

 

[SUMOTOY]

Hi I have an A343F transmission in a V6 Prado. For steep descents I wanted to make an override to manually lock the Torque converter to improve engine braking & control. Controlling the TCC from SL (blue wire) terminal on the ECU, I have found that the TCC will manually lock in every gear except first which is obviously where it is needed. It won't lock in 1st regardless of where the tranmission selector is. I haven't tried tracing it back to the transmission to see if there is any control mechanism between the ECU & transmission which may disable TCC lock in 1st. Is this because of hydraulic valving, or do I need to trace the wiring? Thanks Phil

You would need to fit one of our Extreme Recalibrated Valve Bodies to over come this problem. There is a 1st and reverse gear override that stops the loc-up from working. All of our Extreme valve bodies have this feature removed regardless of if they are fitting a relay lock-up or not. You can't just hard wire the lock-up either as you will burn the transmission out if the loc-up is left Off for to long. We sell a relay manual lock-up kit that solves this problem.

From;
Wholesale Automatic Transmissions

I see no problem with his answer. "Phil" errored in that he went after the higher gear O/D lockout circuit, not the torque converter lockout circuit that would allow lockout in all gears. I bet the relay Rodney sells is wired to the brake circuit to disengage the solenoid during braking. That's the best way to make this mod work IMO. A very sophisticated system could make it work with the factory Trans ECU. As I don't have a lot of interest in this mod for myself, the Rodney kit seems the easiest. But the using the factory diagnostic connector could make this much simpler, and easily removable.

I don't think this is hard, nor magic. It would appear from Wildsmith's own post that he stalled his truck, Rodney's mod didn't solve the stalling problem on the 343, it's apparent he only rigged it so that brake application to the relay disengages it. Exactly my thinking, but that over-ride also a default function within the factory Trans ECU. Again, from the FSM, I see no reason why the 80 *needs* the valve body modification. I suppose it could work as he claims in the 343 trans he references. I see no reference to that as an internal function to the 442 trans.

Scott J

 

[SUMOTOY]

A442F Series vs 343 80 Series Transmission Dislcaimer

Just to note, I have the FSM for the A442F Transmission used in the 1993 and 1994my FZJ80. This mod should apply to the 442 series transmisions with electronic lockup torque converters 93-94my (er, Christo you have the A442F listed as a "mechanical lockup converter" on your website under 93-94...). It's my understanding that the 343 uses a different and more sophisticated Trans ECU, and I do not have that FSM. That said, this modification should prove beneficial to either transmission. And, a side note that the only known install so far on Mud Forum, of the "Extreme" mod was to the 343 in Wildsmith's rig referenced in the other thread.

In addition, that could well mean there is pressure line relief built into the hydraulic circuit of the 343 and 442 in reverse or 1st. I tend to doubt it is a hardware hydraulic mod (more likely a trans ECU input/output signal cancel "phil" missed above, and/or Rodney is a smart marketing guy), but I don't know this for sure. For the purpose of this thread, I will speak only to the A442F transmisson and Torque Converter lockup as defined by the FSM.

Here is the Rodney Lockout relay, looks standard issue. No differentiation between "80/100" equipped with 442 or 343, my educated guess is that the 343 probably has protection built into the other three solenoids that requires the valve body mod. I see no reference to it in the 442 transmission, but it's quite possible the TC hydraulic pressure is too high requiring valve body mods. Interesting, Rodney also claims the 442 application as 1991-01 LC80/100 series. Not true in the US market apparently? Given the beating I took on the gearing thread by well-educated listers, I might call particular attention to the benefits Rodney claims with this mod wrt descents....

Wholesale Automatic Transmissions

FYI

Scott J

 

[landtank]

this sounds good. My concerns would be that the TC and 1st clutch pack could handle the forces being applied on a very heavy rig and that there were some safe guards in place against stalling the engine.

How much benefit do you guys think this will provide? I lost my front brakes a few months ago up in the mountains and had to come down in 1st gear lo range. It really wasn't too bad and very manageable. Just curious how much this mod would have helped that situation.

 

[SUMOTOY]

this sounds good. My concerns would be that the TC and 1st clutch pack could handle the forces being applied on a very heavy rig and that there were some safe guards in place against stalling the engine.

To either the 442 or the 343 you are applying more force to the clutchpack, because of the Torque Converter "up to" 1.8:1 Ratio unlocked, vs always 1:1 Ratio locked. The Rodney mod appears to use the brake switch as the cancel mode for the lockout, that should prevent stalling unless speeds are lower than idle speed first gear (during crawling). You could put in a momentary contact switch that defaults to off for wheeling. The problem I have with the rocker switch is that's not really an offroad/crawling mod, that's an on-road 3rd/4th gear lockout mod. At low speeds you need to release that solenoid very quickly to avoid stalling. I don't think the brake cutout is enough when the speed gets low enough (I'm extending this as a new thread in my research on gearing mods, but in the context of the gearing thread wrt crawling - not onroad highway speed TC lockout).

How much benefit do you guys think this will provide? I lost my front brakes a few months ago up in the mountains and had to come down in 1st gear lo range. It really wasn't too bad and very manageable. Just curious how much this mod would have helped that situation.

The benefit should be multiple. Without lockout, coming down a hill, the first place reverse engine torque is going is to the torque converter as heat, so reverse engine torque will never be directly driven to the gears. The torque converter is designed to not 'fight' overrun during Neg Teng events, quite the opposite, it can get out of hand quickly. If you lockout the torque converter, you have true 1:1 gearing/engine braking. Think of it as driving down a slope in a manual shift first gear vs with the clutch pedal partially engaged (only worse).

It's also imperative that the CDL is locked during wheeling, especially descents. This will assure ideal brake force distribution, delaying the onset of brake overheat as well.

The lockout mod itself should require less brake application vs a truck descending a hill without it.

HTH

Scott J
94 FZJ80 Supercharged

 

[Tools R Us]

I agree that it would be helpful for trailer towing, cruising dirt roads, etc, but for “real wheeling” the terrain has random texture. If you stand and watch a group of rigs cross a set of obstacles, it’s very visually evident who has seat time. Drivers with a lot of seat time are much smoother, use the tools available to modulate their speed, reducing harsh movement. There are a few strategies to accomplish this:

The traditional technique is using gearing. Select a low gear and allow the motor to modulate speed, depending on rig weight, gear ratio, motor, etc, little/less/no brake is needed. On a relatively light rig, with low gears and relatively high motor reciprocating mass/compression, this works great.

Now enter the ~5-6000lb bus! It’s pretty much a given that your going to need brakes to smoothly lower that mass smoothly off of an obstacle, of course it depends on gearing, etc, but for our purposes true.

As an experiment, find a parking block, pull up with a tire ageist it, then apply power to go over it. With no brake you will have too much power at the top and fall off of the other side, the ~6-8” drop will compress the suspension, possibly (depending on spring rate/height) hit the frame/body on the obstacle. Now try it with brake, as it starts to climb apply brake, more at the top and even more as it descends. With a little practice you should be able to do it so smooth that an onlooker wouldn’t know that your went over a parking block, just see a slight smooth body raise/lower.

With gears and a locked clutch the same thing can be done, degree of success depending on how low the gear. What happens is the power side of the drive train is loaded, it climbs, as it descends the load is switched to the coast side of the drive train.

On a heavy rig the problem is in the power to coast transition, there is always some driveline play, so the rig rolls a couple of inches, gaining momentum, then catches. This isn’t good, you may be on a slippery surface can’t, don’t want to slip, need to be smooth and the direction change impact/hammer on a heavy rig is very hard on drive train parts, so a good driver will anticipate and apply brake.

The heavier the rig, the more important/often brake use becomes, so simply controlling off of the brake switch is out. Say your making a long decent, there is a hole/ledge/step part of the way down, as you approach you slightly push the brake, the clutch instantly disengages, rig lurches forward, nail the brake to bring it under control, etc. Down hill is where I want to be the smoothest, not the best time to introduce potential jerkiness. You could monitor brake system pressure and control it at some point, but would it be the same climbing, downhill, etc? My guess is that software would need to be involved to make it truly useable off-road, probably why manufactures didn’t introduce it years ago?

I was going to control it with a momentary switch on the steering wheel, but after wheeling the pig gave up on it. Realized that a fluid coupling (torque converter) is a very good thing on a heavy rig, it greatly reduces shock loads on drive train, extending component life and makes driving smoother. Loading the torque converter and modulating with brake may seam crude, but it works well and the ‘80 systems have been well proven to take it without issue.

 

[SUMOTOY]

I agree that it would be helpful for trailer towing, cruising dirt roads, etc, but for “real wheeling” the terrain has random texture. ...
>...
I was going to control it with a momentary switch on the steering wheel, but after wheeling the pig gave up on it. Realized that a fluid coupling (torque converter) is a very good thing on a heavy rig, it greatly reduces shock loads on drive train, extending component life and makes driving smoother. Loading the torque converter and modulating with brake may seam crude, but it works well and the ‘80 systems have been well proven to take it without issue.

I disagree with many of your premi and conclusions. Component life is not extended, in fact, even Rodney claims it is reduced without the mod. The reason: The fluid in the torque converter ADDS 'up to' 1.8:1 *more* load to the driveline by definition, and that is not a constant below 2200rpm = massive trans heat at low speeds. That is the the win for the 'other side' in the continual debate between wheelers - autobox vs grannies.....

Reading Wildsmith's actual experience this appears to be a good mod without my overcomplicated rising voltage idea. The amount of lockup on the 442 trans is controlled by voltage, 8 steps from no lockup to full lockup. I suspect that any *experience* with the mod would dictate if Rodney's simple brake mod is enough, or if other mods need to be made. WRT "real wheeling" I claim this is just incorrect conclusions.... If you lock the center diff, the connection between front and rear driveline has more shock than the connection between engine and transfer case. And it defines the transition example from on torque to reverse torque you give.

A torque converter truck will always have less shock load than a mechanical connection will because even if you "lock" the torque converter, it is a fluid lock, not a mechanical gear lock like CDL. Specifically, the 'shock load' transitions you claim to feel have nothing to do with the engine connection to the driveline. These poor blokes with their manual transes and high torque diesels!

Looking *just* at the discussion of 'better' braking with gearing claims going downhill in another thread, this mod absolutely would yield better gearing gains than using the torque converter. Overrun torque is a major offset to diff gearing to an autobox torque converter on reverse engine torque.

My warped brain believes the bottom line appears to be addressing *only* stall speed of the truck to account for as many scenarios as necessary, nothing else. Why? Because every 80 with a manual doesn't appear to have these driveline problems or excessive clutch wear, or shock loads causing undue control disadvantage to the autobox wheeler. And by definition they have the advantage in hill descents.

I have no experience trying lockup TC climbing rocks, but I have had lots of major torque converter overrun in my 4R during hill descents. I see issues to overcome climbing, but none of them monumental, and the gains to this mod potentially very good. When you "dance" with the brake, the relay shuts down the lockout anyhow, so that should not be at issue. By definition just making the 'on engine torque' or 'on reverse engine torque' *without braking* to be a constant 1:1 ratio.

In lieu of 'gearing' for downhill advantage, it sure would seem this mod has a lot more benefits regardless of transfer OR differential gearing in low speed downhill wheeling.

I'm actually quite surprised there is no BTDT on this forum in the US, and only 1 guy on the forum total (UK). I'd love to hear more from Wildsmith on this mod.

My .02 arbitraged thru the rising peso

Scott J
94 FZJ80 Supercharged

 

[alkaline747trio]

So what does this mod do for us 440 guys? Does Rodney's mod work for the 440s?

 

[-Spike-]

What happens when you are decellerating down a slope and you need to tap the brakes? With this mod it sounds like when you touch the brake pedal, the truck is going to surge forward when the TC unlocks. Sounds ugly. The way it's set up now it's fairly predictable. Also, you'd lose the extra torque provided at the higher RPM's when climbing an obstacle, unless you shut it off. My first impression is that this mod would not be desireable.

-Spike

 

[Cruiser Jimmy]

So what does this mod do for us 440 guys? Does Rodney's mod work for the 440s?

Logan,
I don't think what Scott wants to do can for work our trannys. Where the 442 uses ele. solenoids to open or close a gate, the 440's have hydraulic pressure that moves pistons and spring. The 440's hydraulic pressure comes from the oil pump and the governor delivers the different signals needed to open the pistons.

 

[landtank]

I'll re-read this thread in the morning but I think Ill leave it to someone else to prove out as viable.

 

[alkaline747trio]

The governor is electronically controlled, I was under the impression that this was for the governor solenoid anyways. Although I wouldn't be surprised to find this untrue.

 

[SUMOTOY]

So what does this mod do for us 440 guys? Does Rodney's mod work for the 440s?

Short answer = I think no. As Cruiser Jimmy states, it' my understanding too that the 440 does not use electronic lockup for the torque converter. Hence my dislcaimer that I am speaking to the A442F Trans in the 93 and 94 80. The concept should apply to the 343, but I don't have that FSM specific to the operation of the electronic lockout. If indeed there is some electro-hydraulic solenoid that controls lockup of the TC on the 440, then the older the generation trans, the easier this mod will be to accomplish successfully and simply.

Scott J
94 FZJ80