Hey all, I have a 2004 silverado 2500 6.0L

I just did a body swap a couple weeks ago, changed all computers, gauge cluster, everything. The truck runs and drives great, just having a shifting issue.

**** points seem to be right, and consistent, tow/haul is working well, but when I'm driving down the around 80-90 km/h the truck is running about 2000-2200 rpm.

In town doing 50-60 km/h it runs 1500-1600 rpm as it should..

Anyone have any ideas why the rpm wont drop at highway speeds?

Thanks.

Chris

 

I'm not hugely familiar with the newer Chev 2500 but I believe it has the 4L80E or possibly even 4L60E. If it doesn't feel exactly right at cruising speeds, the torque converter may not be locking up. 90KMH = 55MPH (I had to Google that one). If I recall, I used to drive these trucks thousands of miles for work and I remember the tranny shifting or torque converter locking up somewhere around 55-60 MPH. Can you run a scanner on the PCM to see if it has any codes for the transmission? On some vehicles the transmission codes do not set a CEL. If it is perhaps low on fluid inside the torque converter itself, it may not function properly. I've felt them stutter and shake the vehicle when trying to engage when low on fluid. Transmissions can be a PITA to get the fluid level where it needs to be.

 

I'm not quite sure what you mean by body swap. You also changed each computer? Please specify what model you swapped from and the drivetrain that model had. If for some reason the PCM you had put in used a different transmission that could be why.