I have a 2001 ss with 70000 miles. About 10000 miles ago I had the transmission back flushed and the troubles began. Since then the engine clunks hard when shifting. It doesn't matter how fast or slow I seem to drive. Plus to add to the confusion it doesn't do it all of the time and when it is in gear it drives nice and smooth. I have had the filter and fluids changed 3 times, I have had the speed sensor changed, the throttle position sensor changed, one solenoid replaced. The only thing left is the pressure control solenoid. Now, when this clunking starts to happen there is a whining noise coming out of the engine area that changes pitch with the engine. If I turn off the car for a couple of minutes it will run just fine. Has anybody else encountered this and since found the solution?

 

Yep! My car 04 LS is doing th same thing.

 

I have a similar problem, but it's only when slowing to a roll and then accelerating, it'll clunk kinda, kinda like a worn u-joint issue. Other than that it's good.

 

Hummmmmmmmmmmm Seems like an odd problem to start after a flush, whine you say? Just a hunch but I would check all vac lines and connectors under the hood and especially anything around the trans dip stick area. Almost sounds as if something could have been knocked loose...

 

Well, guys I took my car to the dealer and the diagnosed it to be the valve body. All together it is going to cost me $950. They checked everything so they told me. They said that the noise that I heard was coming from excess pressure in the valve body which would cause it to shift hard. I will let it know. I guess on the other hand since this is costly, it comes with a warranty and a guarantee. So if it doesn't fix it, its on their tab to find it and correct it. I will post what I find.