Helping a buddy figure out a modded truck he bought. It's a 2006 Silverado 6.0 that is stock except for a turbo and a TAC module.

The issue we're having is that at heavy or WOT the RPMs climb, will hit roughly peak torque at 3500 rpm and then hang there. The truck still accelerates though. Quick googling says this is a converter issue but we aren't sure what that means in terms of a fix. A new converter? A better converter? Any ideas?

Video of the issue:

 

Sounds like you need to get off the gas pedal before you blow that thing up, what is that clatter noise? Definitely doesnt sound happy. You had another post saying stock truck on 8 pounds, that's a big red flag there. You need to log the truck and habe someone look over the tune who knows what there looking at.

 

Thats what we're looking into. Theres a ton of issues with the truck so im trying to cover as many bases as I can. Most of my experience is with manual transmission cars, have never done anything extensive to an automatic which is why im here asking.

 

My suggestion would be to log the truck and upload that here and then list every part you can possibly name that the truck has on it, the more info you post the better response you will get, as you see you havent gotten many responses yet, they don't see the information needed to help your situation so there not responding. Post truck model, engine, engine internals, if any, cam specs if any, injector part number, turbo, if the truck is on stock ecu, transmission is truck, convertor, rear end will gear ratios, you get my drift?

 

The fact that everything is stock Is 1 problem.... Has any one looked at the tune?