1996 Suburban 6.5l diesel cannot go beyond 30mph

[Rain Carpio]

I have a 1996 suburban 6.5l diesel and just recently overhauled the transmission and changed pmd, fuel filter and fuel injection pump. During test drive, it wont go beyond 30mph. If i try to push past that, rpm just go higher. Appreciate any idea to get this fixed. 

[swathdiver]

I would look at the injection pump and the transmission's torque converter.  Do you have access to a bi-directional scan tool like the Tech-2 for diagnostics?

[Rain Carpio]

I got brand new injection pump and torque converter plus changed the tcc valve  regulator with a kit as well. It literally, when it hits 30mph, the rev becomes so high. Could it be a speed limiter thing? Do 96 gmc's have speed limiters already? 

[swathdiver]

2 hours ago, Rain Carpio said:

I got brand new injection pump and torque converter plus changed the tcc valve  regulator with a kit as well. It literally, when it hits 30mph, the rev becomes so high. Could it be a speed limiter thing? Do 96 gmc's have speed limiters already? 

I read your post mister.  Even new things can be broke and not work.  

[Rain Carpio]

Noted Sir

[KARNUT]

It’s sounds like it’s not shifting out of first gear. If you’re getting the RPMs it should shift to second and go faster. Try not pushing the accelerator to the floor. Ease into the throttle is doesn’t take many RPMs to hit the next gear and go faster.


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[Rain Carpio]

Thank you for this... 

 

[wreckdiver230]

it does sound like a shifting problem as stated above

 

[Rain Carpio]

Sent the truck to a diesel specialist but they didnt figure it out as well. But they gave me some ideas like signals from sensors, tps etc to ecu. I had the cables cleaned and last night did 70-80kph... I'll try to use the truck everyday to observe before going on a long drive. Thank you everyone.