My auto has just recently started shifting extremely harshly. I took it to the dealership and they said it was 'probably' a valve sticking and that it would cost $1200 to repair. Anyone else ran into this problem? If so, was there a cheaper alternative?

Just to let you know, I had the auto trans. fluid changed and the filter replaced and that didn't help.

 

Scan it and see if there are any trouble codes for shift solenoids. They are cheap and can be replaced by dropping the pan. If you keep driving it with it shifting hard all the time, you will end up with more damage that will cost $1200.

 

We'll see... I'm going to it scanned sometime tomorrow

 

This may or may not fix your problem, but in my case a flush seemed to fix it. When I scanned my car I had a P1870 transmission code. The hard shifts don't happen all the time do they? Just after you've been driving for a while? Then when you stop, turn off the car for a few minutes, start it back up, does the car drive fine? These are the symptoms of the problem I had.

I talked to a GM repair guy also and he told me the same thing you heard, you need to replace the valve body, etc... and i will cost $1,200 or you can buy a new transmission. I wasn't about ready to fork over $1,200 for a tranny problem that didn't happen all the time, so I did some research on the Internet and read there are a bunch of other people who have had the same problem with their 4l60e. In one of the posts I remember someone saying that sometimes the valvebody sticks and a simple flush will clean up the stuck valve. What causes the hard shifts is after you've been driving for a while and the valve is stuck, the line pressure eventually gets pretty high and soon enough the valve opens allowing a huge gush of fluid to go out.

When I talked to the guy at the dealer where I was getting my tranny flushed, I told him about my problem and he said he'd heard of that problem and that sometimes a tranny flush is all it took to fix it. I figured for $100 it was worth a try, plus I went ahead and installed a transmission cooler also. So as far as I can tell the problem is gone, it hasn't happened again.

 

Yep, EviLBoX, thats exactly whats happening. I had my fluid changed once already but if this keeps happening I may have it done again and see if it helps at all.

 

Did you have it flushed or just get the fluid changed? I'd opt for the flush.

 

Which gears are shifting harsh? If it's all gears then possible P1870. This is a slipping TCC, when the pcm sees this it gives the trans. max. line pressure. Typically the CEL doesn't light because it takes 2 consecutive drive cycles with this failure, but the pressure stays high for, I think, 50 drive cycles. If this is the case then go to an aftermarket shop, the can sleeve your valve bore (tcc reg. apply valve #380) for a lot less than a new valve body. Also have them check the valve under the tcc sol. in the pump. If you pull the tcc sol. off, there is a small hole in the valve stop. Push up on the valve through this hole, it should move about 1/2" and spring back, if not it can cause the P1870 also.
If your shifts are harsh only in one particular gear the check accumulators, spacer plate damage at the check ball locations, and also sticking valves. If your shifts are harsh all the time, have them scan the pcm for codes and check the line press. before throwing parts at it. Good Luck!

 

All gears shift harsh but if I turn the car off then back on everything is normal.

I'm gonna try that flush EvilBox, I wasn't aware there was a difference between change and flush until your last post, thx