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I'm trying to figure out why my car has hard shifts. It only happens sometimes and when it does, if the car goes over 2000 rpm i can hear a whine. I'm not sure if it comes from the valve train or the trans. It made this noise before and I checked the oil and it was near the bottom of the hash marks on the stick so I added more and it solved the problem, for the moment. Tonight while driving it started slamming into gear again so I pulled over to check the oil again. The oil level was good, the car only sat for 2 or 3 minutes I got in and it drove away with no problems. I was thinking that it might be a shift module that's getting hot but I'm not sure. Do y'all have any ideas?

The most likely cause is a sticking pressure control solenoid in the transmission. If you have the car scanned, it will probably show code P1811 - long adaptive shift. Most code readers will not see this code, and it will not set the check engine light. This will set maximum line pressure, which will cause the banging shifts, as well as the whine that you hear.

The long term fix is to have the PCS replaced, which requires having the side cover removed from the transmission. The sub-frame on that side has to be dropped, and the axle pulled to accomplish that.

A short term fix could be adding a can of SeaFoam's Trans Tune to see if that frees up the solenoid. Drive for a week or two, then drop the transmission pan to change the fluid and filter. Procedure for that is in techinfo.

A work around that can alleviate the symptoms is to install a shift kit.

Is there any kind of techinfo on replacing the pcs. I've called around and it's pretty pricey. Most places just replaced the pcs and one replaced it and did work on the valve body also. I've heard prices from $400 to $800. I'm just trying to figure out what the best course of action would be.

Get the TransGo shift kit, a new filter, and some new ATF. See if that band-aids your symptoms to your liking.

Don't just get a cheap shift kit. You want the springs the TransGo has. Those will do the best job of working around the flaky electronics.

The PCS is a bear to replace. The folks who have done it have reported it's not a fun fix at all.

I talked with an aamco shop after posting on here. I was told $200 installed, which to me seems reasonable. I'm prob gonna take it out there this week to get a more definite price.

If they can do it for 200, thats a very reasonable price...

Thats a little too reasonable in my opinion. I would be a little concerned on what kind of job they do.

I do agree with that... I know I would charge a lot more... ... ... ...

ericm88 wrote:I talked with an aamco shop after posting on here. I was told $200 installed

I used to work with a guy that used to run an aamco. He told me that they would intentionally "quote" very low on the phone just to get YOUR car on THEIR hoist, then tear the car apart and tell you it needs a $2500 overhaul but if you didn't want to fix it there was no charge...just that you had to tow your car home and take your tranny with you in boxes. Of course nobody wanted to take their tranny home or anywhere else in boxes, so they almost always had them overhaul it.

Not saying they all do that, but I know at least one of them used to.

After looking around I'm seeing that aamco has a pretty bad reputation. I'm going to try to talk to some people around here and ask about that shop. The Trans Plant said around $400 do you think that is a more reasonable price?

That sounds fair. The parts alone must be at least $100. The labor being 300, I'm guessing they charge about $75/hr? I would have to guess the book time is at least 4 hours? It's not an easy job. It's more common for this repair to be $500-$600 or more.

Would changing the fluid and filter help with this problem? I bought the car used and do not know the last time the fluid was changed. I was told that since I don't know the last time it wouldn't help at all to change the fluid unless a full flush is done. But I've also been told that full flushes are not good for the tranny.

edit- I checked the fluid to see if it could be low and it was at the right level but there were alot of bubbles in it. Any ideas on the bubbles?

Bubbles = bad. There's something whipping air into the ATF. When air whips in, the ATF doesn't do what it should.

Change the fluid in the pan, and over-fill the pan by half a quart. Then see if you get bubbles.

I've changed half the ATF in my car 2-3 times, and flushed the transmission twice. The bad PCS is a pain in my rear that the shift kit I mentioned earlier helps out with.

Do you think that whatever is causing bubbles in the fluid could be the reason the PCS is acting up? I also noticed that after changing the front engine mount the hard shifts and whining seemed to go away until recently. I'm not sure if they are related or not.

They may be related, they may not be related. I think the low fluid level may have caused air to get sucked in with the fluid, explaining the bubbles. Put some more fluid in to see if the bubbles disappear.

Look at your other mounts. If one went bad, it strained the others, and could have caused another mount to fail.

Get all the shift solenoids replaced. They come in a 3-pack. I first tested mine and had a long shift trouble code. I had my 111k tranny done recently by a local shop for $400, but the side tranny gasket was shot too so that cost $60 their at cost price. $460 total out the door. I didn't have bubbles, but my car has hard shifted for 2 years and have made a few posts on this forum about it before. Fixed the problem. GM transmissions even when new or repaired don't shift silky smooth, but it's so great not having the transmission hard shift whenever it gets hot.

Well I think the bubbles were the clue. The fluid was low, I added enough to bring it back up to level. The car shifted hard right after I put the fluid in, then after stopping and restarting the car it didn't hard shift again during the next 30 miles of driving I did. I'm gonna give it a few days to see if anything happens and I'm also going to change the fluid and filter and switch to a 180* thermostat to keep things a little cooler.

Also, a small transmission cooler will help keep the 4T65 happy during the summer. I have a giant one on my LeSabre. It's massive overkill, and the transmission is never above ~170 in the summer.

ALLDATA States that it takes 5.2 hours to replace the solenoid.

Since I'm at school and don't need my car I took it into the shop. They said that it might have an intermittent miss in the engine which is causing all of this, or it is both engine and tranny. I'll keep you all updated on what might be wrong.