Allthough it's not for my Camaro maybe still someone can help me out with a little problem I have with my 1990 Caprice Wagon. It has the Olds engine with a 200-4R behind it. When cold the car runs great and shifts perfectly. But after a longer ride on the highway and everything is warm, it feels like the trans will downshift very late. It will make the car vibrate a little just it's gonna stall but. After that it also upshifts very soon when accelerating, making the car very unpleasant to drive. Driving around town there seems to be no problem, it only occurs after a longer ride on the highway.

What can cause this to happen? Maybe the TC keeps being locked when hot?

Any thougths ara welcome!

No such thing as an Olds V-8 engine in 1990 that I recall??

pdq67

It does sound like your torque converter is staying locked. Not sure of the circuitry on that model but there's likely a TVS (themal vacuum switch) on the engine that will enable the lock up circuit once the engine is warm...

theres a lockup solenoid in the pan that goes alot. any tranny shop has a universal one that will work for you. pm me if you cant find one near you. i can ship you 1 if you want.

Thanks for the reply's guy's! pdq67: For some strange reason they still used this engine in the wagons only up to 1990. It is the last of that model ('78 to '90)

I will try and find the TVS (I do have the GM manual) and to get my hands on a new lockup solenoid. There's a Chevy dealer nearby so I will try that first (they are horrible with they're prices).

Might this also be what's causing it to upshift very quickly? It feels like the car is in third gear by the time I'm driving 10 miles an hour...or maybe it doesn't upshift but locks the converter again??