Torque Converter locking up too early

Seeing as I am on a role with posts tonight I thought I would add another. My 2002 Grand Prix GT, 3.8 has an issue with the transmission. I will be going about 25-30 at about 1500 rpm and the torque converter will lock up and shutter. This happens at other speeds as well. Just wondering if this is a valve body issue? I've had the epc solenoid and the tcc solenoid replaced about 3 years ago because the the long shift issue.

Thanks!

Any PCM codes set?

A common problem on the 4T65-E is the TCC solenoid, this may be your problem. I would assume the car does not do it when you manually take it out of OD? It could also be a faulty TPS (throttle position sensor). I do not recall how to test the TPS. Maybe someone can chime in on that...

Edit: sorry, I just realized you indicated you replaced the TCC apx 3 years ago. You could always try installing a mild shift kit to see if it helps your problem.

I never thought of taking the car out of OD to test. I will try that tomorrow and let you know. I did not put the tcc solenoid in, a tranny shop did. Would that be something i could handle my self? I did do a full body off on 67 corvette roadster. I've just never taken apart an automatic trans before.

I wouldn't suggest tackling the TCC yourself as it does involve splitting the transmission apart. As I indicated, you could try installing a mild shift kit. I've installed many of them from ZZP (click link (http://zzperformance.com/grand_prix/products1.php?id=570&catid=105)) Real easy/cheap to install.

I drove the car is Drive instead of OD and it still shifted funny, just not as bad. Must not be the torque converter.

I would check out the throttle position sensor. A missfire will cause a shutter feeling too. How long has it been since you've had a tune-up?

I've done a tune up recently. It is not that, it is something to do with the tranny. it does not shutter all the time only when it does it at low rpm and mph. It happens when the car downshifts.

How do I test the TPS? When I had the TCC replaced it did it when it was upshifting.

Oh I sure am hoping some body can find the cure for this, and posted it!! I'm having the same issues with my 01 Impala 3.8

Going up a hill about 30-35 mph around 1500 rpm in 3RD gear the RPM's will bounce to 1700-1800 rpms. If I give it gas or let off the gas it stops surging.

* I have checked for Vacuum leaks
* Replaced the TPS
* EGR Valve and Gasket
* Cleaned the Throttle Body and replace rubber gasket.
* Replaced the MAP sensor
* Replaced the IAC (Idle Air Control Valve)

Looking to do the Plugs and wires this weekend. Last time I changed them I had 110,000 miles and Have 193,000 miles now.

To eliminate the TCC.. From what I have read on hear, correct me if I'm wrong. But the TCC will only act up in 4th/OD and normally at HWY Speeds.

Also I'm not getting any codes either.

How do I test the TPS? When I had the TCC replaced it did it when it was upshifting.

I personally have never tested a TPS, but I found a writeup (click link (http://www.ehow.com/how_4489318_troubleshoot-tps-sensor.html)) online. Not sure how reputable it is, but you could give it a shot. I'm sure someone else will chime in as well.

UPDATE I disconnected my battery last night and hooked it back up this morning. (like stated in other posts)And this morning I could not get the car to fishbite at all. I'm not 100% convinced it is fixed. The weird thing is, now it feels like it shift through all gears a little different.

On the way home I will see how it drives, and reply back.

Update?

I had a problem with my RPM's bouncing up and down at about 1500 rpms or 35 mph. I disconnected the battery overnight and I no longer have this problem.. But now I know what they mean by "fish bite". I get that now when going up a hill I can be in 3rd gear and doing 30 mph or OD doing 60 mph. The rpms are not effected to much by this, however they my drop down a little. It's hard to tell, because I never know when its going to do it.

To me it feels like the car is shifting hard. But I can be locked in 3rd gear doing fine then it will do the "fish bite" once or twice some times on a hill some times not. I'm going to replace the plug wires this weekend (depending on time) since this set has 65-70k on them already.

It is strange how this problem started the day after I disconnected my battery overnight, and the other problems has went away.