Hello everyone,

I own a 1997 Pontiac Bonneville SSEi with almost 130K. This vehicle runs excellent with the exception of the transmission. When the car is really warm, it will shift very hard in all gears. I did replace both the transmission fluid and filter. People were telling me it could be the TCC solenoid, but I'm a little leary on that because if it was this, then the faulty solenoid should produce a code (check engine light) which it doesn't.

Has anyone ever experienced anything like this? If so, what was the problem?

Any responses would be greatly appreciated!!..:)

Thanks!

Pete

I woud go with a PCS solenoid causing your problem! Not all problems manifest themselves with a trouble code! If the PCM sees a signal and think the signal is right it won't set a code. There is no trouble code for a hard shift like you are looking for.

Thank you for your reply Flatrater.! I will look into this.

Pete :)

If you suspect TCC get it scanned, Autozone will do it free. Trans codes don't always turn on engine light because it is a different sytem like ABS. I had a TCC code show up and no light.

Flatrater, couldn't the hard shift be the beginning of the tcc valve bore wear, resulting in pressure loss then the pcm compensates by commanding full line pressure, thus hard shifts, usually this will set 1870, but not always.

Is it a 4t60E or 4t65E?

If a 4t60E I'd say it sounds like a bad modulator, or vacuum to the modulator...

If its a 65, Id concur with the PCS, or valve body.

That's funny,you just answered a post dated 2-5-2004.

indeed... lol