A343f Transmission: manual Torque Converter Lockup..anyone tried? (1 Viewer)

[ga12r1]

@geanes did you ever pull the trigger on the lockup controller? After reading this thread I’ve been watching my scangauge when towing and can definitely tell when unlocked just by rising trans temp. It sure would be nice to be able to lock manually, it would definitely help keeping the temps down if nothing else.

 

[staggrlee]

I have the Wholesale Automatics HD valve body/lockup kit and and an external trans cooler/fan fitted and tow a Moby1 that is >3500lbs loaded out. I have 33" tires and 4.88 gears (with a SC, headers/custom exhaust) and full armor/sub-tank etc, my truck tips the scales at about the same ~7500lbs. I've done about 12k miles towing with it.

From personal experience I can tell you that you're headed down a very expensive path adapting a 100 for what you intend to tow and -- when you've done everything you can do -- you'll still want a diesel. You'll have enough power, using low range if needed, to get over anything eventually, but the 8mpg (maybe 10) with Premium is disgusting and you'll have a total range of at best 200 miles on a stock tank.

Took it to HIH last year (but left the trailer in camp obviously) and I can tell you that some of the Rocky Mtn. passes are brutal towing 3000lbs with a 100 no matter what you do but the lock up kit will definitely allow you to keep the temps low(er) both up and down. I find that no matter what the grade is, if I select gearing to keep my AFR >12, RPMs at 3-3.5k and use the TC lock up when I see AT temps rising, that I can keep trans temp below 170F. Cruising along it holds temps in the 130-150 range.

Did throw a P0777 shift solenoid DTC last weekend over Stephen's Pass here in WA. First time I've seen that. I suspect the GenII controller isn't as smart as it thinks it is and doesn't always spoof signals back to the TCM the way it should. Or my solenoid is going bad from the lock up kit.

Just be glad that you can deal with Cruiser Brothers. I got my kit direct from WA and the logistics of dealing with Rodney there was a pain. He was great, but it was an error-prone-several-months process. Mostly due to a vacation he took in the middle of my order and leaving it to someone else at WA to sort out the proper fitting to use their temp guage/sending unit. The only Fahrenheit gauge they offer is analog. I never even look at it and depend on my Scangauge so that was pointless. Luckily you can skip that whole mess.

 

[geanes]

@geanes did you ever pull the trigger on the lockup controller? After reading this thread I’ve been watching my scangauge when towing and can definitely tell when unlocked just by rising trans temp. It sure would be nice to be able to lock manually, it would definitely help keeping the temps down if nothing else.

Actually ordering this week. On my trailer off-road shakedown run today, I left it in O/D off and would routinely see the trans temps climb to 200+ when climbing short off-road hills. Hit 213 at one point. It rapidly cooled back down within a minute or so to 160 once I was on flatter terrain. But, 3rd is definitely not staying locked up with O/D off. I can feel it when it does and the temps drop, but it almost immediately starts the slip again so the temps start rising.

On the highway, with OD on, I stay around 150.

Today's ambient temps were 95+.

 

[geanes]

I have the Wholesale Automatics HD valve body/lockup kit and and an external trans cooler/fan fitted and tow a Moby1 that is >3500lbs loaded out. I have 33" tires and 4.88 gears (with a SC, headers/custom exhaust) and full armor/sub-tank etc, my truck tips the scales at about the same ~7500lbs. I've done about 12k miles towing with it.

From personal experience I can tell you that you're headed down a very expensive path adapting a 100 for what you intend to tow and -- when you've done everything you can do -- you'll still want a diesel. You'll have enough power, using low range if needed, to get over anything eventually, but the 8mpg (maybe 10) with Premium is disgusting and you'll have a total range of at best 200 miles on a stock tank.

Took it to HIH last year (but left the trailer in camp obviously) and I can tell you that some of the Rocky Mtn. passes are brutal towing 3000lbs with a 100 no matter what you do but the lock up kit will definitely allow you to keep the temps low(er) both up and down. I find that no matter what the grade is, if I select gearing to keep my AFR >12, RPMs at 3-3.5k and use the TC lock up when I see AT temps rising, that I can keep trans temp below 170F. Cruising along it holds temps in the 130-150 range.

Did throw a P0777 shift solenoid DTC last weekend over Stephen's Pass here in WA. First time I've seen that. I suspect the GenII controller isn't as smart as it thinks it is and doesn't always spoof signals back to the TCM the way it should. Or my solenoid is going bad from the lock up kit.

Just be glad that you can deal with Cruiser Brothers. I got my kit direct from WA and the logistics of dealing with Rodney there was a pain. He was great, but it was an error-prone-several-months process. Mostly due to a vacation he took in the middle of my order and leaving it to someone else at WA to sort out the proper fitting to use their temp guage/sending unit. The only Fahrenheit gauge they offer is analog. I never even look at it and depend on my Scangauge so that was pointless. Luckily you can skip that whole mess.

Thankfully I'm only towing 1100lbs total. I'm on 33s with the 343f transmission on stock gearing. Definitely not looking to regear or do the entire valve body assembly. Figuring the torque lockup kit will do what I need for what I tow. Just want to be able to address temp issues. I have done the Pin7 mod so I can run in 4Lo with manual control of the center diff lock. I figure I might have to use 4Lo on some of the passes and just kind of poke my way up. I guess with the lower range gearing and the torque lockup, I should be able to get over Raton and a few other passes in 4Lo 3rd locked and not see huge trans temps. Hitting the 200+ on a few occasions is pretty concerning.

 

[staggrlee]

Was referring to the Dominator trailer you're looking at in terms of weight. You'd be OK in Texas with just the TC kit and a Aux cooler I imagine. Even with the heat.

@ 1100lb with the 3rd/2nd TC lockup you'll be fine out to Silverton I'm sure. It really is nice to push a button and watch the AT temp drop.

 

[geanes]

Was referring to the Dominator trailer you're looking at in terms of weight. You'd be OK in Texas with just the TC kit and a Aux cooler I imagine. Even with the heat.

@ 1100lb with the 3rd/2nd TC lockup you'll be fine out to Silverton I'm sure. It really is nice to push a button and watch the AT temp drop.

Yeah, the Dominator is on a semi-permanent hold.....home HVAC system went out and needs replaced! There goes $6k in a heartbeat. But, need AC in central Texas.

My little Morris Mule knockoff will have to do for the foreseeable future.

 

[TexLexican]

What should rpms be with the 4 speed at ~70 mph and on flat ground? I’m at about 2500 in overdrive but can’t really tell if the torque converter is locking up.

 

[Malleus]

What should rpms be with the 4 speed at ~70 mph and on flat ground? I’m at about 2500 in overdrive but can’t really tell if the torque converter is locking up.

I assume you have an A343F; your rpm will be determined by your tire size and gearing. Here are the specifications:

I'll leave the math to you

 

[TexLexican]

I assume you have an A343F; your rpm will be determined by your tire size and gearing. Here are the specifications:
View attachment 3397056
View attachment 3397053
I'll leave the math to you

Hmmm… those mph numbers seem awfully high

 

[Malleus]

The shift points or lock up points? I agree the shift points look high, but it does say "throttle valve fully opened", so maybe that's what they measured on 4WD day at drag week. The second image is from the repair manual.