Whats the concensus on launching with the torque convertor clutch engaged as far as damage to the transmission? This would be on a good quality setup like Goerend's or DTT.
Feels like Id get a lot more power to the ground with the TCC locked up with the mystery switch but I worry about wearing material off the friction discs.

 

I don't think that is possible, if you lock the switch without the truck moving.......?? Now once the truck starts moving you can lock it and it will be hard on the input shaft. Some tranny builders use that method from what I see.

 

If you lock the TCC too soon, you'll kill the engine.

 

I throw the switch once I hear the truck take 2nd gear.

 

i would agree with the second gear method, locking before second gear will at some point destroy even the best built transmissions. if your loosing that much power at the low end then you need a lower stall higher efficiency converter. HTS transmissions also ranks up with goerend and DTT.

 

Right, obviously you cant go from a stop with it locked. I meant heavy acceleration.
Sounds like I need to look into a convertor with a low stall speed when I do order up my transmission then.
So higher RPM and gears 2,3,4 are better for the TCC. I wonder if Ill be impressed enough with the new convertor and trans that I wont need the TCC.

 

Kawi600:

Talk with Dave Goerends. He has a couple of choices for the stator. He makes a great low stall one that matches up nice with the triple disk. You'll also want/need the billet shafts if you're locking it up that early. I don't need/miss my torque converter lock up at all with his set up, and he's great to do business with.

Paul

 

__________________________________

Yup! But IMHO whats more important than a lower stall is higher efficency
Your stock converter in GOOD shape is in the 60-65% range where some of the better aftermarket ones are up in the low 90s however you really need alot more than stock power to take advantage of that tight of a converter

 

Hm.. so as I move to a lower stall speed, I lose efficiency? Or is it the other way around? Ideally Id like to have a lower stall speed to match the torque curve of the motor, right?
If that is the trade-off maybe Ill look at a higher efficiency one since fuel mileage is so bad.

 

I'm no expert but I dont think efficiency has anything to do with stall speed other than if your converters to tight and your stalls to low It really needs to be matched to your HP level. Talk to any of the reputable builders and tell them whet you have and what you will have for power and they can set you up. Be carefull on your choice of dealer and do your research on their policies for future mods, like if you see twins in the near future then tell them cause that will make a difference in what they recommend. Probably the best advice I can give is to spend a 1/2 hour on the phone with each of the big 3 and choose from there.

 

My truck used to have a POS trans-go shift kit in it and at that time I tried a switch on it. I could switch on at a dead stop and the TCC would lock up at 1-2 shift. Talk about a violent shift - extremely hard and huge tire smoker. I removed the switch after 1 days use as I was sure the shafts wouldn't like it at all. My feeling is a lock up switch is good for slowing down with an exhaust brake but full throttle upshifts is asking a bit too much from stock shafts.

 

This was the train of thought I had and pursued a couple of weeks ago. I went with a billet TC that has a lower stall speed (I'm guessing 300 rpm lower). At the same time, I had the Trans Clinic in CO. Springs install a VB kit from SMR. They also did the diffs and went to Mobil C4 ATF. They claimed (and took the time to explain their reasoning) as to why the efficiency is improved. The TC is a single disc unit, which suits my application just fine.
Here are the impressions...Everything is just more solid. With the box off or on, the truck is just more responsive. There is no wasted time on gear changes, and the lockup leaves no doubt the combo is up to anything I will ever ask it to do. The owner (Don) also informed me this TC will run cooler and help preserve the tranny. The shop was absolutely great to deal with, I felt the price was VERY reasonable, with the TC being 1/2 the price of what I had been seeing, the job was done in 1 1/2 days, and most importantly of all, it was done right the first time.
I just did a 1800 mile round trip from CO to AZ. Light load, heavy head winds going, some snow, some very cold temps (9*F in Show Low,AZ) even a few miles of 4WD. Now, keep in mind, I was trying hard for mileage, had some Redline fuel additive, and really worked at running below 70 (not fun), but overall, I averaged an honest 19mpg.
I should mention that I switched to Redline 15W40 full syn. motor oil too. I was really wanting to break into the 20+mpg. range, but it simply was not to be. Coming back, I filled in Show Low, AZ, and made it to Fairplay,Co on one tank. That was 625 miles. I was being real good until I kinda got into it with a young guy in a Subura who was running pretty good. The overhead was reading 0, but I only had about 20 miles left til the stations, so I cranked in the box, and totally "Smoked" him. It took 32.5 gal to fill, but I am figuring I could have gotten in another 1/2 gallon if I wanted to use the eyedropper.
Bottom Line.....There are alot of trucks on this site that would make me look really slow, but with the mods done, this ain't no "Girly Man" truck either, and I am one very happy camper, and I DO think the lower stall speed, along with being more responsive in city driving probably does increase the efficiency.

 

Well with my stock convertor being pretty old Im guessing its shot internally. even that 60% efficiency isnt so good. Bet I pick up a more than a few MPG with this swap.
The 4.10's are also killing me but theres not much I can do besides going up in tire size and that doesnt help much.
Id love to swap out the ring+pinions but thats about 1000$ in parts and labor if Im lucky.

 

The converter won't really help highway mileage that much as your TC clutch is engaged while at highway speeds but they will help city driving mileage.

 

most of my driving in the winter is in the city, but that turns around in the summer since Im hauling my toys around.
Acceleration is awful right now too, the motor has to spin to 2500rpm before I go anywhere.
All this talk of the TCC engaging harshly makes me wonder too how much clutch material is in the bottom of the pan