I'm new here and I've searched the board for my problem. I've found some posts pointing at the solenoid valve assembly? I bought my car back in August, had a transmission flush in September and this problem starts. It hard shifts only when the car is at operating temp (200) and it only hard shifts every other time I drive it.

I also read a service bulletin talking about an excessively oiled aftermarket air filter (I think it was on the boards somewhere) causing a problem like this. I've got a Fram Air Hog installed but have never oiled it. Could this be the cause?

Thanks for any help.

2001 SSEi

could you please describe that hard shift in more detail

as for the air filter there are numerous 2000+ models runing a K&N without any problems

No strange noises or anything. It does it in both drive or if I manually shift through the gears. Just a loud thud when it shifts.

Did you clean the solenoid valves? Or did you pay someone to do it? And how much did it cost? I've got a day off tomorrow and if it'* not too much I might take it in.

Mark Fahey, I hate to ask a stupid question,but do you know how the dealer cleaned the solenoids?Other than a tranny flush which for some people gives a temporary fix or none at all, I don't see a cheap easy fix.The reason I say this is that the solenoids are an electromagnet which may well attract ferrous wear particles and if you've ever seen the magnet in the tranny pan,there seems to be no shortage of ferrous wear material.

You have to access the valve body to work on the solenoids. This means dropping the drivers side sub frame, tire, hub assembly, steering linkage, etc.
I did this last night with a buddy and it took 4 hours to do working off the floor. You would need a service manual before even attempting it.
Try having your tranny flushed before diving into the valve body, inspect the tranny filter for debris, may show signs of trouble beyond the solenoids?

i have a 2000 bonne, bought used last sep. with 126K on it. Just this month(NOV.) i had to drive about 200 mile for work, about my 3rd hour into driving, i noticed a change in my transmission, i was trying to pass someone, when my car felt like someone pulled the clutch out to fast, but thats impossible since we all have A/T, and like that you it only happens at norm. driving temp. I went to where i bought it from to have it checked out, they took it to a transmission place, they said "the soleniod is sticking at times" they also said"the soleniod is inside the transmission and the only way to get to it is to pull the whole tranny out" which would cost me about $500-$600 they said. but on the cheaper side they give me some kind of additive to see if it would loosin' the soleniod, and to try that for a week and that was yesterday(11/04/04) so now i'm waiting, and it hasn't happened yet but i haven't drove my car for a long distance yet also. don't what kind of additive but will find if you want?

Maybe try some seafoam transmission additive? If you do use it make sure to get a transmission flush a few hundred miles later.

Please DEATHbloomz if you can find out what kind that would greatly help. Your description is exactly what is happening. I called the dealer here and they said it would cost about $400 to change the solenoid (they said they can't clean it).

I had thought of using an off-the-shelf transmission additive, but from what I've seen on the boards here: synthetic fluids don't mix well with Bonneville transmissions.