Last week my 2002 GMC 3500 with a duramax went into "limp" mode and was stuck in 2nd gear. I took it to the GM dealer and they replaced a switch and fixed the problem. After feeling that I had the truck back in 100% operating condition, I purchased the "Juice Attitude" from a distributor and they installed it as well. It was on the #3 setting and the truck ran ok and felt stronger. While driving back to work, I tried some spirited driving to see how much more power I could feel and I noticed that the truck wouldn't shift out of 2nd gear and that the PRND321 indicator was unlit in Drive. It was stuck in 2nd gear again. I drove back to Edge Products distributor and we unhooked the "Juice" so that I could take it to GM dealer without them giving me too much grief, and when I drove away the SES light was on, but at least the truck upshifted and downshifted. So the problem seems to occur and stay a problem while the "Juice" was connected. What do you think is going on?

Can you get the codes scanned? When it happened did you shut the truck down before going back to the juice distributor? If not it could be a coincidence that the "limp mode" reset after shutting the truck down and not because of the juice removal.

Check the four connectors and be sure they are tight. I wrap mine with large cable ties. I had the same problem with a previous version of juice 4.61 and I took it out and went to the dealer where they diagnosed it with a communication failure to the computer. They checked the flow rates on the injectors and reset the codes. I took the juice 4.61 back to the shop I bought it from and a week later they gave me the updated 4.81. Plugged it in made sure the plugs and pins were all connected well and have not had a problem since (3 months now).

I took it to the GM dealer and while the SES light was not on. The code that it was displaying was 0733, which was transmission related. Fixes, included a transmission flush with filter replacement to replacing the transmission. The other notable item was the that detents between N - D - 3 are sloppy, and when it sometimes engages in gear from neutral to drive it is with a "not so gently" clunk. I am getting a feeling that my woes are in the Transmission.
I wonder if I should invest the time to have the dealer troubleshoot the problem, or go to a good independent transmission shop?

Suncoast V & triple disk converter = time to play.

:exactly:

Your "spirited driving" limped the tranny. I have done that on level 5 but not on 3.Once the truck is shut down for a few minutes it resets itself and alows the tranny to shift normal. The SES light will stay on for a few key cycles. Not a huge deal but i wouldn't make a habit of it.

By keeping the attitude in level 1 and 2, the limp mode has not reared its ugly head. I am going to set the option to defuel between shifts and raise the bar higher (trying levels 3 and what the heck 4 & 5 too) to see what happens.

Did you not set it to defuel on shifts before? I havent hade any problems with mine(knock on wood) I run it on level 4, 3 on low boost & defuel all shifts

That is correct. Before I didn't have it set to defuel between shifts. Everything seems to be working fine now...knock on wood. I feel good enough to go and spend some more money on "go fast" parts. Does anyone have a suggestion for an exhaust system and a low restriction intake/filter housing?

Mark

Go fast parts - tranny upgrade.
Lower EGT's and louder sound - Exhaust and intake modifications.
I believe that when they changed out the parts on your tranny than most of your problems were solved and brought back your tranny to original working loads. you still can limp in level 3 or higher though depending on how hard you are on the overdrive gears.

swish cheese the air box & S.S. 4" exhaust will fit the bill

Thanks for the tips. I have an 1989 3.8 litre turbocharged v-6 Trans Am that has turned a best of 11.79 in the quartermile (daily driver) and it would be a hoot if I could get my truck to turn twelves at the drag strip. What would it take to get a 3500 crewcab dually to be a twelve second truck?

tranny, big program, lift pump & nitrous