1st gear delete for Duramax TCM

bogger

bogger

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Mar 22, 2010
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So I just tried my new tcm tune tonight which is just basically 10% over stock and the truck pulled damn good.. seemed like it was really like the higher rpms on each shift... My question is to you guys with a 1058 converter and Suncoast Stage 4 in my daily driver would I benefit in getting a spare tcm just for pulling and go with a first gear delete and 15% or just have it bumped up to 15% and keep 1st gear? Thanks for your time guys..
 
bogger said:
So I just tried my new tcm tune tonight which is just basically 10% over stock and the truck pulled damn good.. seemed like it was really like the higher rpms on each shift... My question is to you guys with a 1058 converter and Suncoast Stage 4 in my daily driver would I benefit in getting a spare tcm just for pulling and go with a first gear delete and 15% or just have it bumped up to 15% and keep 1st gear? Thanks for your time guys..
Click to expand...

There is no reason so run a different TCM for a second gear start. There are a couple of ways to scrip it in. You can set it up to work in towhaul mode. Or you can set it up to work only in low range. If you are sled pulling, you definitely want a second gear start.

I guess you could set the second gear start for non tow haul mode as well, but thats kind of foolish unless you have a dedicated drag truck.
 
I started using 3rd gear start this year and it has worked well so far. Go for it!
 
The only prob with a 3rd gear start is the converter might lock, but it also may not. Even if it does, it might take a few more seconds than normal. With a 2nd gear start, you can get plenty of rpms out of it for a hard launch, and the 2-3 shift will help the converter lock.

Also, you may have to experiment with the tcm tuning. I could never get mine to do it unless all shift schedules(tow haul, 4wd lo, normal, etc.) were changed. I think 5 speeds can be tricky like that, but 6 speeds will repsond when just the tow/haul schedule changed.
 
ya the reason I just wanna delete the first gear is cuz I don't quite think I have the ponies to come out in third. you figure i'm probably right at the 500rwhp mark which aint really a whole lot. I guess I never knew you could set up the tcm based upon whether or not you had the truck in 4lo?? if that's the case then hell ya i'd do 15% with a first delete and leave my normal driving mode at 10%
 
Looking at your Sig VS Operators, i wouldn't think you have enough ass for a 3rd gear start.

But yes, there are like 5 shift timing tables, Regular, tow haul, 4 lo and 2 tables for over heated or something like that. Its been a good long while since i have had them open.

Im not sure what you mean by trans tunes that are a % over stock?
 
04jimc said:
The only prob with a 3rd gear start is the converter might lock, but it also may not. Even if it does, it might take a few more seconds than normal. With a 2nd gear start, you can get plenty of rpms out of it for a hard launch, and the 2-3 shift will help the converter lock.

Also, you may have to experiment with the tcm tuning. I could never get mine to do it unless all shift schedules(tow haul, 4wd lo, normal, etc.) were changed. I think 5 speeds can be tricky like that, but 6 speeds will repsond when just the tow/haul schedule changed.
Click to expand...
I to had to change all tables on a 5 speed to get them to do what I requested.
 
Ild at least try it in third if your taking off with an xfactor sled, at least once anyways
 
thanks for all your help guys.. I wound up getting a spare tcm for a 100 bucks.. I know I know you said I could just use my original but its all good.. this one came from an 01 and i'm gonna go with just first delete cuz I def know the truck don't have the nut to go 3rd. when I said a % my tuner basically stated that's the percentage he was raising the shift points at all if that makes sense. Dylan Spink is doing it up for me and hes a very knowledgeable tuner. what should i come out at?? 15psi? 10 psi? a certain rpm?
 
I'd try 3rd for the hell of it chad on a loose track nothing up north here is tacky
 
what do you think about for say like Truck Fest Rich? would you contemplate 1st gear 4 hi? I heard Derek was doing that but I didn't think many people even tried that anymore?
 
Chad, I think you'd be a lot better off to stay in low range on the transfer case. First high is a 10.97 final ratio vs. a 13.5 in 3rd low. I'm not a fan of 3rd gear starts unless you have a lot of power.
 
Ya I don't think I quite got the nuts for 3rd either Josh. So my new TCM is on its way with 1st delete. Excited to try it out next week
 
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