Have a 97 z71 that i just purchased with 180k. Truck runs like its brand new and shifts flawlessly until your driving like 40 minutes and then it will shift into 2nd harder than normal. Once you turn it off and get back in it the problem is gone. Its not hard enough to break your back but its hard enough to tell its there. Read something about a shift improvement kit but I dont know how to do that. Kind of seems like its getting too hot. Thanks

 

I suggest a trans flush, just got the trans flushed in the wifes car. it used to bang into fourth, flushed it, and now shifts like its new.

 

But would that make sense even though the thing shifts like its new until you drive for like 40 minutes

 

my 95 used to shift hard all the time.. cold or warm.. i got a trans flush and it smoothed it out driving about 20 miles thru town

 

I think it would make a difference

 

makes perfect sense. fluid pressure is different at different rpm's, speed, and engine load

 

yeah i just had rough shifting in my 04 Z71 from 1st to 2nd and i flushed the tranny. smooth sailing from about 50 miles of driving it around town.

 

Well i guess ill try that. I just heard that the 4l60e had issues with the valve body and was putting 2 and 2 together. Also since it only does it when it gets driven for about 40 minutes what do you think about adding an aftermarket transmission cooler

 

aftermarket trans coolers are always a good idea, as long as they are the right size. issues can arise after being warmed up and/or at certain speeds as the fluid density and amount of pressure it makes constantly changes, depending on the fluid temp, pressure, engine load.

 

Well what kind do you recommend i buy. Im just scared the trans is going to get too hot. I love the truck I just wish this wasnt happening... When i checked the fluid today it was still nice and clean looking and not gritty at all