To re-gear or not to re-gear?

[linuxgod]

Don’t the Aus market diesel guys often install a TC lockup switch? Could probably be done on a gasoline rig just as easily..




I had this same thought and o reached out to a couple of shops and both said to change out my Valve Body. I never dove deep into that but assume this would change potential shift points etc.

Richards in Australia apparently sells both a lockup kit as well as a transmission ECU remapping kit. (They also have an engine ECU remapping kit but that appears to be for diesel only). I emailed them to find out about compatibility and testing with the US vehicles

LOCKUP KITS & REMAPPING - Richards Auto Electrical

LOCK UP KITThe principle of this modification is to achieve more direct drive from the transmission. By locking the torque converter we can prevent the constant hunting caused by locking and unlocking the converter. It is important we still maintain the factory driveability of the vehicle and...

richardsauto.com.au

The Project 200 page talks about the remap at LandCruiser 200 - Torque Converter Lockup and Gearbox Remap - Project 200 - https://www.project200.com.au/torque-converter-lockup/#remap. Of particular interest in red below:

• Lower engagement speed for 6th gear: Now engages at around 92km/h in Drive, under light throttle.
• Higher throttle before kicking down from 6>5 and 5>4: The map ramps, so (for example) It drops into 6th at 92km/h if you are at <20% throttle. By the time you reach 100km/h, it needs ~50% throttle before it kicks back to 5th.
• Smoother gear changes: The remap applies torque reduction during gear changes. This makes a huge difference to gearshift quality, particularly when the lockup kit is active.
• Multiple maps: The remap has different settings for 'Drive', Drive+PWR', 'S' and 'S+PWR'.
• Allowing 5th and 6th gear to operate in low range: I didn't go with this option, but it's available if you want it, so you're no longer limited to 4th in low range.
• Elimination of MIL light: The remap extends the parameters required to generate the P2757 fault code, and stops the malfunction light sequence from appearing (although it still logs any fault code internally). The fault light can be a side effect of the TC lockup kits. I got this code perhaps once or twice a year, but haven't had it at all since the remap.

I think it would be particularly niceto be able to reprogram the transmission shift points and behavior when in S+PWR (treating that as a towing-specific mode) and maybe D+PWR (tuned for highway but non-towing configuration) but leave "D" set as the factory did, for instance.

 

[Artie]

Is 7th or 8th ever possible while towing if you go high enough on the re gear?

 

[linuxgod]

Is 7th or 8th ever possible while towing if you go high enough on the re gear?

Definitely not with my 6 speed

I can lock up in 5th with the 6 speed which is equivalent to 7th. But I regeared to 4.88s… couldn’t have done it previously

 

[Artie]

Definitely not with my 6 speed

I can lock up in 5th with the 6 speed which is equivalent to 7th. But I regeared to 4.88s… couldn’t have done it previously

Interesting.

I’ve used “D” only a hand full of times, I always go right to “6” unless I’m 80 mph on the interstate. Otherwise, it bounces around 7 and 8 and it makes me crazy and all this is without a trailer.

 

[linuxgod]

Interesting.

I’ve used “D” only a hand full of times, I always go right to “6” unless I’m 80 mph on the interstate. Otherwise, it bounces around 7 and 8 and it makes me crazy and all this is without a trailer.

That’s pretty typical. The top gear will hold at 80 if you are totally stock and on totally flat land.

Regeared I have no issue holding 80 in 6th even on larger tires and with abysmal aero. I also get maybe 13 mpg if I’m lucky when doing 80.

 

[Artie]

That’s pretty typical. The top gear will hold at 80 if you are totally stock and on totally flat land.

Regeared I have no issue holding 80 in 6th even on larger tires and with abysmal aero. I also get maybe 13 mpg if I’m lucky when doing 80.

Given my weight, 34 inch tires, terrible aero, and frequent towing it’s starting to seem like going to the higher ratio is a win/win on the 6th speed, I have the 8 speed so I wonder how that would behave. I like the idea of sticking with a Toyota gear in the 3.9 but given the vehicle stats 4.88 could be the move.

 

[bloc]

Given my weight, 34 inch tires, terrible aero, and frequent towing it’s starting to seem like going to the higher ratio is a win/win on the 6th speed, I have the 8 speed so I wonder how that would behave. I like the idea of sticking with a Toyota gear in the 3.9 but given the vehicle stats 4.88 could be the move.

4.88 would be very, very deep gearing with your 8-spd. I believe someone did it and expressed they had gone too far.. though I'm struggling to remember who.

Teckis' charts showing effective freeway gearing should tell the tale. 3.9s on an 8-spd give you ~7-8% more RPMs than stock gears/tires at a given speed, let alone 4.1, 4.3, 4.56..

 

[lx200inAR]

Given my weight, 34 inch tires, terrible aero, and frequent towing it’s starting to seem like going to the higher ratio is a win/win on the 6th speed, I have the 8 speed so I wonder how that would behave. I like the idea of sticking with a Toyota gear in the 3.9 but given the vehicle stats 4.88 could be the move.

Forgot to hit send on this earlier...

4.88 would be a big swing. There is the middle ground with 4.30 that the 6speed guys switch to using Tundra and early 100 series parts.

 

[CharlieS]

Given my weight, 34 inch tires, terrible aero, and frequent towing it’s starting to seem like going to the higher ratio is a win/win on the 6th speed, I have the 8 speed so I wonder how that would behave. I like the idea of sticking with a Toyota gear in the 3.9 but given the vehicle stats 4.88 could be the move.

I have a similar setup ('16 - 8 speed - 34s and loaded heavy, front and rear metal bumpers and aux tank) and 3.91 are perfect for everything from high speed interstate to crawling trails. I'd be cautious to go to 4.88. 4.10 might be okay.

 

[krice118]

indycole?

4.88 would be very, very deep gearing with your 8-spd. I believe someone did it and expressed they had gone too far.. though I'm struggling to remember who.

Teckis' charts showing effective freeway gearing should tell the tale. 3.9s on an 8-spd give you ~7-8% more RPMs than stock gears/tires at a given speed, let alone 4.1, 4.3, 4.56..

 

[Artie]

I have a similar setup ('16 - 8 speed - 34s and loaded heavy, front and rear metal bumpers and aux tank) and 3.91 are perfect for everything from high speed interstate to crawling trails. I'd be cautious to go to 4.88. 4.10 might be okay.

Thanks for talking me down.

 

[bloc]

indycole?

It was a more recent build, I think. Lots of discussion on whether to do lockers if I remember correctly.

 

[linuxgod]

Given my weight, 34 inch tires, terrible aero, and frequent towing it’s starting to seem like going to the higher ratio is a win/win on the 6th speed, I have the 8 speed so I wonder how that would behave. I like the idea of sticking with a Toyota gear in the 3.9 but given the vehicle stats 4.88 could be the move.

If you have the 8 speed you probably want 3.90 gears. Maybe possibly 4.30 if you’re feeling aggressive and either want to go 37s or really want a tall crawl ratio. 4.88s would be too much gear for the highway on the 8 speed setup

 

[TeCKis300]

It's a balance of concerns and it's very possible to go too far. Part of the criticisms of 8-speed owners is already that there's too much gearing on the bottom end. And too many shifts. Evidenced by comments of shift smoothness and preference for the 6-speed. Focusing on highway cruise is going to miss issues with drivability around town, part throttle low speed downshifts, etc.

There's also the aspect of tuning. The transmission tuning was designed around assumptions of speed and load for various gears. Can't just drop in that dramatic of a change and expect it all to work. Even minor tailoring can result in unexpected changes to shift quality and torque converter lockup.

Maybe it can help to put this into perspective. 4.3s to the 8-speed is equivelent to 5.29s on the 6-speed. No one is asking for that. Maybe with 42" tires?

 

[NoClue]

I feel the 4.30s are fine with my 8 speed. I'm on 35s at 3.7 tons fully loaded. works great when towing / crawling. I don't drive the car over 75MPH.

 

[Artie]

It's a balance of concerns and it's very possible to go too far. Part of the criticisms of 8-speed owners is already that there's too much gearing on the bottom end. And too many shifts. Evidenced by comments of shift smoothness and preference for the 6-speed. Focusing on highway cruise is going to miss issues with drivability around town, part throttle low speed downshifts, etc.

There's also the aspect of tuning. The transmission tuning was designed around assumptions of speed and load for various gears. Can't just drop in that dramatic of a change and expect it all to work. Even minor tailoring can result in unexpected changes to shift quality and torque converter lockup.

Maybe it can help to put this into perspective. 4.3s to the 8-speed is equivelent to 5.29s on the 6-speed. No one is asking for that. Maybe with 42" tires?

I just read your previous post with that 5.29 comment when going back through this thread. Information overload… almost.

 

[TeCKis300]

I feel the 4.30s are fine with my 8 speed. I'm on 35s at 3.7 tons fully loaded. works great when towing / crawling. I don't drive the car over 75MPH.

There's certainly more hardcore owners that know what they are building their rig for. That might get lost in certain discussions where the assumption is to build a more balanced rig. The spectrum is less about what is right or wrong, and more a trade of what works best if building for more specific use cases. So even my comments should be taken with a grain of salt and more about going in eyes wide open. Good to hear this setup works for your needs.

 

[VooDoo2]

Don’t the Aus market diesel guys often install a TC lockup switch? Could probably be done on a gasoline rig just as easily..

@VooDoo2 any input?

Yess we fit them to Diesels and petrols. Works awesome and keeps trans temps low. Also works in low range and low speed (sand) driving

 

[bloc]

Yess we fit them to Diesels and petrols. Works awesome and keeps trans temps low. Also works in low range and low speed (sand) driving

@linuxgod will probably be happy to hear that

 

[linuxgod]

@linuxgod will probably be happy to hear that

Yes I would be.

I'd reached out to Richard's in Australia to see if both the TC lockup as well as the Transmission ECU remapping has been tested with US vehicles (or at least with the 5.7L spec V8's). They never replied. Sounds like the TC lockup should work at least. @VooDoo2 any experience with the transmission remap?