Corvette Shuddering in Overdrive....please help!!

[92lt1auto]

This story is going to be kind of long, but I want to give you the most information I can. The problem started on my way to Cruise-In V, and continued to get worse on the way home from the Cruise-In.



Roughly 150 miles into the trip, while running close to 75mph in overdrive (OD), I pushed approximately 1/2 way down on the accelerator pedal to increase my speed. To my dismay I felt a pretty hard shudder (I would compare the feel and sound to when you run over the "wake-up bumps" on the shoulder of the interstate) that would not go away unless I let up of the gas or pressed harder on the gas to make the tranny shift down out of overdrive. In the 270 miles to Bowling Green, I could only get it to duplicate the problem 3 times. On the way home however, once the vehicle warmed up.....I could get it to "shudder" almost everytime. While the vehicle is shuddering, if I manually shift it out of OD, the shuddering goes away. Also, pushing the gas just slightly to increase speed does not cause it to shudder. I have to really put a load on the engine, basically I have to really get it close to downshifting before it will shudder. I checked the tranny fluid once I got home and it was at the bottom "FULL HOT" mark and was still pink in color. The fluid did not smell or look burnt. The only thing I noticed was that the fluid was a little "foamy". Any Ideas???

Also, on maybe (or maybe not) an unrelated issue; when I got back home I stopped at the gas station. I left the car running when I went inside, and came back out and hopped in the car. When I put it in reverse and gave is some gas my ASR Active light came on and I heard the ASR making its "noise". When I let off of the gas the ASR turned off. I then put it in drive and pressed the gas, again the ASR kicked on. I let off of the gas and turned off the ASR. Once turned off and then turned back on, it worked correctly. Any ideas as to what this could be? One trip back to it's home (Bowling Green) and now my Corvette is possessed. Please help!!!

 

[BigRed]

Sorry to be the bearer of bad news there bud...


The foam is usually from parts either from the torque converter or the bands gettting shook up. It "stirs" up the fluid or its getting air from outside (possible crack/leak) and thats what your getting on your stick.

Thats the norm but go to your transmission shop NOW! Have them scan the car and look for possible computer problems and visually look at the trans on the hoist.

However.

The car COULD be having a computer complication and therefore throwing a limphome code. That would tell the transmission to stay the hell out of OD. Plus the ASR problem sounds related.

Good news is the transmission is VERY easy to R&R I do believe the labour time is around 4.5 hours on the auto and 3.5 on the standard.

Plus if the transmission is rebuildable (rarely aren't) it'll be not to bad because it is in the end a hardcore chevy and nothing TO exotic for the builder to contend with.

Hope that helps

I had a 98 Chev Half-Ton do the same crap to me (minus the ASR) and it turned out being a cracked case...amongst other smaller things.

 

[jmccloud]

Overdrive shudder

Had two cars (both Buicks) with your exact symptoms and both had a bad plug wire. Check the trans but a set of wires is a lot cheaper, hope that's it.

 

[motorman]

This story is going to be kind of long, but I want to give you the most information I can. The problem started on my way to Cruise-In V, and continued to get worse on the way home from the Cruise-In.



Roughly 150 miles into the trip, while running close to 75mph in overdrive (OD), I pushed approximately 1/2 way down on the accelerator pedal to increase my speed. To my dismay I felt a pretty hard shudder (I would compare the feel and sound to when you run over the "wake-up bumps" on the shoulder of the interstate) that would not go away unless I let up of the gas or pressed harder on the gas to make the tranny shift down out of overdrive. In the 270 miles to Bowling Green, I could only get it to duplicate the problem 3 times. On the way home however, once the vehicle warmed up.....I could get it to "shudder" almost everytime. While the vehicle is shuddering, if I manually shift it out of OD, the shuddering goes away. Also, pushing the gas just slightly to increase speed does not cause it to shudder. I have to really put a load on the engine, basically I have to really get it close to downshifting before it will shudder. I checked the tranny fluid once I got home and it was at the bottom "FULL HOT" mark and was still pink in color. The fluid did not smell or look burnt. The only thing I noticed was that the fluid was a little "foamy". Any Ideas???

Also, on maybe (or maybe not) an unrelated issue; when I got back home I stopped at the gas station. I left the car running when I went inside, and came back out and hopped in the car. When I put it in reverse and gave is some gas my ASR Active light came on and I heard the ASR making its "noise". When I let off of the gas the ASR turned off. I then put it in drive and pressed the gas, again the ASR kicked on. I let off of the gas and turned off the ASR. Once turned off and then turned back on, it worked correctly. Any ideas as to what this could be? One trip back to it's home (Bowling Green) and now my Corvette is possessed. Please help!!!

unplug the TC wiring and see it this problem goes away,if it does the are 2 things to check,1 the soleniod in the transmission that locks the TC could be bad or 2 the TC itself could have bad bushings.

 

[Robertwav1]

I noticed the exact same thing on a 93. Shudder when pressing down on the throttle after your doing 75 MPH or so. I definately felt it...was a trip to Florida from Jersey. This was several years ago now....I just forgot about it! I rarely do that type of trip with my car. Only in OD. I did a tuneup since....but never got it hot enough to do over 75 lately. I have no trans problems...I usually drive around town in drive, not OD. Someone told me once it really beats up a trans to leave OD on in normal around town driving. I usually take it to 2K in drive. Any comments?

 

[motorman]

I noticed the exact same thing on a 93. Shudder when pressing down on the throttle after your doing 75 MPH or so. I definately felt it...was a trip to Florida from Jersey. This was several years ago now....I just forgot about it! I rarely do that type of trip with my car. Only in OD. I did a tuneup since....but never got it hot enough to do over 75 lately. I have no trans problems...I usually drive around town in drive, not OD. Someone told me once it really beats up a trans to leave OD on in normal around town driving. I usually take it to 2K in drive. Any comments?

i never use OD under 50 MPH as the up and down shifting is just wearing out the trans parts plus you have very little engine braking in OD so you are wearing out your brakes.

 

[92lt1auto]

Hopefully the problem will be solved

Well, I work at a GM/Toyota dealership and went down and talked to our GM Master technician on what he thought my problem may be. He said that it was 1 of 3 things. He said he would try the TC lock-up solenoid first since it was the cheapest. It cost me $35 for the solenoid and tranny pan gasket, and $40 for the labor. I hope it fixes my problem! I'll keep you all updated on the problem.

 

[CarDemon04]

that shudder you are talking about is most likely a hard mis on one or more cylinders. The fact that it gets worse and not better as the car warms up leads me to believe it is not spark plugs or wires. one possibility is a burnt valve, or a bad spot on the camshaft(which got worse the more you drove it). another possibility is a defect in the overdrive gear. I am unsure why the computer would have failed, and how that would effect what you are talking about. and before you go spending a ton of money hooking it up to a computer over the foam in the transmission oil.... I'd say go and have the trans oil AND filter replaced(sometimes when the filter gets plugged the pump can't get enough oil and therefore sucks air creating bubbles and foam)... hope that helps, good luck

 

[92lt1auto]

CarDemon04 - When I took it down to talk to the lead GM tech we have here on staff, he hooked it up to the scanner (for free) and found no codes (or anything abnormal).

If there was a burnt valve or bad spot on the camshaft, wouldn't this "shudder" happen in any gear? This only happens in overdrive going 70+ mph. This would put my rpm's at 1,700 or so with 2.59 gears. While the vehicle is shuddering I can take it out of overdrive and the shuddering goes away instantly. I've tried reproducing the problem going slower in 3rd gear at 1,700 rpm's and applying the same amount of throttle and it doesn't do anything.

I've also tried doing 60mph or so in overdrive and applying the same amount of throttle and it doesn't do anything abnormal. I'm hoping that the tech is right and it's just the Torque Converter solenoid. He has to drop the tranny pan to replace the solenoid, so I'll have him replace the filter and fluid (obviously) at the same time.

Thanks!