Late Shifting

I have a 92 bonneville with 170K miles. It still looks and drives great other than late shifting into overdrive that I am experiencing. I have replaced the transaxle filter and fluid recently and the problem still persists. What happens is that in normal accelleration when you reach 60 mph the engine is still in "drive" and revving around 4K rpm, If you slightly let off the gas the engines shifts nicely into overdrive. Downshifting is not a problem. The problem exist between 2nd and drive but it is not as noticeable.

I have check the diagnotic readouts (counting the flashing of the "Engine Lite" when A and B terminal are shorted and I got a code that everything is OK. I have checked the Vacum lines and they seem to be ok.

Does anyone have any ideas or suggestions.

Thanks
Scott

It sounds to me like your tourque converter lockup switch is failing. To my knowledge the only way to replace it is to remove the tourque converter from the transmission to access the inside of the bell houseing, which means virutally removing the transmission from the vehicle. I could be wrong, i have one on my bonneville that is bad, i just disconnected the electrical connection going to it and dropped my overdrive.

Have you noticed any late shifts in the other gears. If so, I would check out the kickdown cable to see if it is properly adjusted. The best way to check a tranny shifting properly is with a 300 lbs pressure gauge, and connecting into a pressure port on the tranny, and reading what pressures you have with the kickdown cable adjusted to the normal setting. Sometimes, it can be a stretched cable. Or needing a good flush. Good luck.