Horsepower Kills...Toasted Allison

[blakmax]

Well it happened to a transmission rebuilder,a slipping,limping Allison LCT1000. Got her apart Friday to discover all shifting clutches smoked.C2toC4's cooked..I expected this but the suprise, two sealing rings on the turbine shaft {input} dug into the ground sleeve like a 200,000 mile transmission.Of course my local Allison supplier does not stock a ground sleeve and claims never sold one. I have only rebuilt six of these units and never seen this. Have to overnite one out Indy for Tuesday.One thing for sure....power enhancements do kill!!

[cowboywildbill]

In your opinion will running with the normal edge on level 3 empty and on level 2 while towing do one in? I always make mine kick down out or OD when pulling any hard grade and I won't let it pull a slight hill in OD while towing when it is under 1800 rpm. So far I have never had a limp or any code or other issue other than a bad Neutraul Safety Switch. I have around 50,000 on it so far. And what do you think the best beef up kit for the allison is for the money for towing.

[blakmax]

C.W.B I am installing a Transgo Reprogramm Kit and Torque Converter Shop sent me a billet steel flywheel section of torque converter. It has twin discs for lockup. Nice piece. I have 55,000 miles this pickup, to answer your power level questions, i think you did! Don,t drive it like you stole it and it will last.
tapper

[LucasEnglish]

My dad has a 02 Dmax and he keeps the Edge on 5 all day and gets on it a min of few times a day and has done it for 30k with no probs yet. We are hoping the tranny will start to show some signs so we can get a good built one in and turn up the power some more. We keep it on 2 for towing.

The truck has 85k on it now.

[cowboywildbill]

Thanks, Let us know how the new parts work out.

[Jim Brzozowski]

TimTapper, thats interesting, you smoked c2 thru c4. I thought I read where the C5 clutches were the weak link, or maybe I remembered it wrong. What kind of fluid and maintenence program on this one?

[blakmax]

S.T.P...C4 clutch pack is what gets hit the hardest in this unit as well as all WORLD TRANSMISSIONS. I have cared for this unit like it was my child until i got my right foot on the pedal...so it is no suprise as to the clutch failure, however the sealing ring issue is a mystery.Transfluid is Valvoline Maxlife part#132622. I use this fluid on heavy duty trucks i.e.Transit bus/ Refuse /Fire. Should see the ground sleeve a.m. and road test p.m. and post tomorrow. Tim.

[Jim Brzozowski]

Tim, once you get that thing back together, you ought to find a dyno to put it on, you must be making some pretty big HP with those stacks. Did you also do the drill outs and install those plugs and springs like transgo says? Just curious, of course you did, its nice to be able to fix your own vehicle. That unit should be a serious hook up with all that new stuff. Everybody goes through it, keep making more power till you find the weak link, upgrade it and keep on until you find the next one if you keep going you'll eventually find the metallurgical limits of most parts. Hope you don't tear up too much stuff, but when you mash the go petal it sure does feel good-- don't it.

[blakmax]

Hello Fellow Duramaximers! I have finished my work here....my master piece...Wow. If you would like my opinion, Transgo got this reprogram kit right. This would not be the first one i have installed, however the first one was a truck with stock horsepower. I did change my lockup shift rpm to 1200 with my laptop for now. Lots to play with and so far NO LIMP!! Tapper

[Jim Brzozowski]

That converter must be really tight to let you lock it up that early, don't know if you could move a really heavy load with it set that low, but at least its programable. I understand that GM is eventually going to a total vehicle computer programable and diagnosis system in a couple of years on all the control modules so hang on to your lap top once the software guru's get hold of it we may all be able to fine tune our vehicles as we would prefer (within limits of course).
Keep us posted on how it does under varying conditions every once in a while.

[blakmax]

S.T.P. ..1100 rpm is where your torque converter locksup. That is the lowest parameter and if i remember 2000 rpm was the highest.Leaning to bring lockup higher due to excessive smoke when converter locks. I love tweaking this beauty.
Tapper

[Jim Brzozowski]

Yeah, thats right, shaft speed not engine speed STP! Duh. I need to get more sleep.

[bobo]

How are you programing the TCM for lockup?