richardbentz

Chevy Celebrity Problem, July 2006

1989 Chev Celebrity station wagon, 2.5 L, 4 cyl TBI, 3 speed auto Xmsn type 125-T,
190K miles.

Description of problem:
This problem does not occur until the engine is at normal operating temperature, meaning driven for 20 minutes or more.

Xmsn in drive and you brake to a stop, the engine shudders pretty violently as you slow down, starting at about 5 mph or so, and then stalls. It will restart immediately in Park or neutral, but stalls again immediately when put into drive, and even reverse. Now this starting and stalling will keep repeating and you can go nowhere. But if you let the car stand for awhile, with engine off, say 5 minutes or so, it will start and drive again. But then after a bit the problem will recur.

When driving on a highway, as you slow down to go through an EZ pass toll at about 20 mph, as you attempt to accelerate again the whole vehicle vibrates with a high frequency which feels exactly like when the right side of your car drifts into the emergency lane and onto the safety warning rumble strip; just like that high frequency vibration. And although it feels like it might stall again, if you accelerate slowly from 20 mph the vibration goes away when speed gets up to about 35 mph. Through playing around with this I found that when that high freq vibration starts, at say 20 mph, it will go away if I manually shift to the 2 position. If you slow below 20 mph then you must shift to 1st for the vibration and stalling threat to go away.

So it would seem to be a Xmsn problem, as if when you slow down the Xmsn stays in 3rd and does not automatically down shift as it should.

Xmsn fluid and filter has not been changed for a very long time. The car has not been driven a lot in recent 2 years and not a real lot in the 4 years before that. I examined the Xmsn fluid and find that it has gone to an orange/brown color, not bright red anymore. Feels and smells ok though.

Questions:
• Is assumption that it’s a Xmsn problem consistent with the symptoms described?
• Has this problem been seen on this or other auto transmissions before? I have never seen it in over 40 years of driving.
• What are possible causes, fixes?
• Could something simple like replacing the Xmsn fluid and filter possibly help?
• What about a Xmsn fluid additive?
• Any other simple and inexpensive things that could be tried with Xmsn in vehicle?
• Cost of a Xmsn rebuild?

Dick Bentz
rbentz@mitre,org

mopar

i dont think its a tranny problem, my truck was doing that exact samr thing, and after $2000 and 2 years, i found it was my distibutor and the distributor pick-up. Also the module in the distributor was crack.

Revredneck

I've seen it a dozen times or more. Your torque converter clutch solenoid is sticking when it gets hot. A quick fix is simply to unplug the electrical connector that goes into the front of the tranny, just above the cooling lines. In order to make a proper repair, you'll need to remove the side cover on the trans by removing the driver's side front wheel and the plastic inner splash shield for access. It's a lot easier than you think. You should be able to get the solenoid at a tranny shop, or a Chevy dealer. The only thing you'll need is the solenoid and a gasket for the side pan. Be sure to support the car on jack stands while you're working on it. Take your time and be careful, and you'll get it fixed in an afternoon. Good luck and God bless.
Revredneck

kcb37

I think Revredneck is talking about the same thing, but my sister had a 92 Corsica, it did something similar not exactly sure what, but it was the torque conver locking up and staying locked. I can't remeber what that sensor was called now. Sorry. I think torque converter lockup solenoid, or sensor.
I would change the fluid and filter too. I won't argue with the distibutor but I would try this first.
Good luck.

richardbentz

I believe Revredneck is correct. I have had some independent input from a knowlegeable local mechanic and he says my torque converter clutch (TCC) is not disengaging. He also recommended unplugging the connector that send a signal to the solenoid. Apparently the TCC engagement (via the solenoid) only provides a kind of "direct drive" which is like another gear slightly higher than 3rd. The impact of not achieving this "direct drive" is, I am told, a very small loss in mpg.

Anyway I did this and am still testing to see if it makes the problem go away.

I'll report back when I have more data.

Thnx to all, especially Revredneck, for your help and inputs.

I do not believe the distributor has any part in this.

Richard Bentz

kcb37

On a clutch it will die if you let the clutch out to quick because it will not slip once the pedal if fully released, the torque converter in essence replaces the clutch pedal by allowing that slip while stopped and starting. When it is locked up it acts like a relesed clutch and does not slip at all, when it is not you lose some power, and mpg. The slip in perfectly normal, that's how they work, you just wont have your lock up. Which is your "gear slightly higher than 3rd"

richardbentz

I have thoroughly tested the vehicle with the solenoid disabled [by unplugging the connector] and the problem is gone, everything is now normal. Further data collection will show if the impact on MPG is significant.

R

kcb37

If it is you know what is wrong, where your sensor is, now how much is it. If you notice a drop in mileage I would suggest replacing it, unless you have to take the tranny off to get to it. If it is easy to get to I would do it.