Hard 1-2 shift....

[pumpedTSI]

I noticed on my 93 GMC Sierra SLE 5.0 that if I "baby" the throttle starting from a stop the 1-2 changeup is soft and not very noticable if it shifts up under 2k rpm.......now, if I go hard on the throttle off the line the 1-2 shift occurs just over 3k rpm and is a "hard" thunk shift.....all other shifts are normal. Whats the most logical cause? My fluid was changed in entirety (12 qts) approx 2k miles ago (fluid only no filter....yet) so its clean and level is good. Is it a TPS issue?

 

[Dszx13]

Not sure. My old 93 would slam first an second hard an normal take off. When I hammered down it was fine. Eventually the engine light came so I could figure it out

 

[pumpedTSI]

On normal takeoff it shifts just fine under 2k rpm but if I hammer it and it shifts above 3k its a hard shift...

 

[willdabeast69]

On normal takeoff it shifts just fine under 2k rpm but if I hammer it and it shifts above 3k its a hard shift...

someone might have installed a corvette servo.

 

[southern_z71_92]

could be a shift kit, cause mine does it and i have a shift kit.

 

[pumpedTSI]

How the hell would I know if a shift kit was installed?

 

[1997k1500Calvin]

and also how do you know if you have corvette servo...my truck does the same thing...seems to shift better than my 88 c1500 700r4 and it was freshly rebuilt..it shifted so soft you could set a glass on the dash with no worries of spilling it...anyways plz info on the servo..ty