1st gear low power

[JimErickson]

Hello all,
I have a 2001 EC 3500 with Duramax and Allison tranny. All engine updates are updated.

I have a problem in first gear. It seems like there is very little power when pulling from a stop. Gets even worse when pulling a load. After turbo kicks in and hits second gear it runs away.

A couple of times when trying to pull into traffic pulling a load it has been scary. Does this is normal or tow/haul mode.

This is not just a little difference. It seems like it has about 1/3 the power that it has when it hits second gear. 2nd gear will push you into your seat while 1st has me wanting to put my foot out and push.

I have a KN airfilter in but no other mods. Can not run Juice or anything like this as it is a company truck.

Also. Has anyone noticed a significant power hit when running AC? Again it seems to take about 25% of power (especially from a stop). On top of that the AC does not really work that well. On highway its fine but during city traffic it sucks.

Thanx
Jim

[IndigoDually]

I believe that 1st gear does run at reduced power. I think the reasoning is due to the gear reduction with how low 1st is. If you had full power the truck would really launch and under load probably sooner or later break something. Once you get moving the power can be applied because you are not really shockloading the system from a standstill. It's kinda like doing a "Neutral Drop". Not very good for driveline components.

I believe that I read this info somewhere a while ago.

John

[slapshot44]

I also have an '01 EC 3500, and it is also a dog from a dead start. I don't understand the reasoning for depowering an automatic equipped truck for the excuse of "making it easier" on the drivetrain components. Its a heavy duty truck for cripes sake. The torque converter being unlocked in first gear should be more than adequate for cushioning the drivetrain. Having max power for getting a load moving from a dead stop should be a prime consideration.

The drive train on these trucks is much more heavy duty than the ones that came on 60's era musclecars, and yet those drivetrains had very little trouble handling many years of service behind engines with higher power ratings than our trucks... my '68 Goat still has the original tranny, rear-end, axles, and driveline, and it has seen many 3,000 rpm clutch drops from a standstill, and just as many powershifts also. (not bashing you John, just bashing the truck programming.)

But, my a/c works fine, once it gets going. It takes about 10 minutes on a hot day to really cool the truck down, but after that it will freeze you out, even on 100 degree days. It doesn't seem to rob too much engine power either.

[mark45678]

some of the ecm updates take a little snap out of the truck! If by chance you had yours reflashed in mid 2001 you should see if you can cet it updated again. To bad there "company" truck you guys would Sh*t if you got a ride in a juiced truck.... no problems with FAST holeshots !

[Southard]

I have had the computer updates done on my 2001 and I just got back from vacation in Colorado. The engine seems to take forever to start building boost at altitude while pulling a trailer. Once it gets to 5 psi it runs fine from that point on. When I went to Colorado last year before I did the updates the engine built boost much quicker. I consider the pickup to be so slow that it is actually dangerous when getting across intersections at altitude.

The air conditioner does not seem to affect performance any at all.