Transmission shifts hard

impala
chevrolet
ls

#1

Every so often while driving in the city my car starts shifting rough between 1st-2en and 2en-3rd gears. If I stop; turn off the engine and then restart it stops. The car has 107,000 mi. and the fluid has always been changed as recomended. Do I have a shift selonoid going out somewhere?


#2

sounds like the pressure control solenoid. It will have to be scanned, and if it has the right codes I think it’s P1811, will need a line pressure test done. If I remember correctly, this solenoid takes around six to eight hours to replace.


#3

Its true that the pressure control solenoids in those transmissions have been a problem. There was, in fact, a TSB from GM about it a long time ago. I don’t know whether that TSB is still considered in effect or has been superceded, but either way a new PCS only may or may not help.

Here is a great website by a transmission tech who apparently loves this transmission (it is a 4T65E): http://www.tripleedgeperformance.com/

Look under 4T65E Problems and you’ll find a description of the intermittent hard shifting problem associated with a P1811 code.

Of course, that only might be your problem. You’re going to need to take it to your best local, independent transmission shop for a diagnosis.

And even though your fluid has been serviced as recommended, most manufacturer transmission service recommendations are terrible. A pan drop/filter change every 30K is best.