Thanks again for everyone’s input! I’m going to give some details for others having a similar problem to try to let them know my thought process (for right or wrong), and why I took the action I did.
2 days ago, the shuddering problem would happen almost everytime the car was at cruising speed (50 MPH and above) and the RPMs fell below 2200 and I lightly hit the accelerator to get back up to cruising speed. The shudder would occur for about 1-2 seconds while the car RPMs increased, and when RPMs went beyond around 2400 RPM, the shuddering would go away. If I maintained the cruising speed in overdrive with the RPMs around 2600 or more, the problem never happened. The shudder felt pronounced, as if I was going over the warning strip at the side of the road, or even a washboard.
Status update: I took the car to a mechanic who did complete trans fluid flush, dropped the pan and replaced the gasket, and replaced the screen/filter, and added 2 two ounce tubes of shudder guard (or something like that… Mechanic pulled a code P1210 (using code scanner), but the code didn’t cause the check engine light (which works) to illuminate. He said that with a quick search, he couldn’t really find the meaning of that code for a Toyota, but found 2 other reports that had the code with similar symptoms as my own. In one of the cases, the code was cleared, seemed to solve the problem, but another code showed up 2-3 weeks later indicated a trans solenoid.
Mechanic said that the shuddering was most likely torque converter clutch shudder, and wouldn’t damage the transmission if it continued. Said it is likely NOT the transmission. He said that it is possible that new trans fluid (and shudder guard) could help lube the torque clutch solenoid, and clean it out to help it out. He said that it was likely that the solenoid was sticking slightly, or getting lazy, or both, causing the clutch to be a bit lazy in engaging and disengaging (thereby causing the shudder). The complete trans flush with 4 oz of shudder-guard. I drove the car on the highway for about 30 minutes, and *might* have felt an extremely slight shudder (when I’m trying to make it happen). So at this point, I’m going to go into waiting mode to see what happens – I have a 500 mile round trip next weekend that could give it a good test.
I’ll back-up now, and give more details about the last couple of days…
I took car to small trans shop. No test drive, just listened to me describe the symptoms. Recommended to get trans fluid flush (which will replace 100% of the trans fluid, as opposed to dropping the pan and topping off the trans fluid which replaces around 1/3 of the fluid), and a 2oz tube of shudder-guard. I said thank you and went to trans shop #2 (Mr. Transmission). I left, but did nothing at this point (i.e., no trans fluid change or adding of shudder guard).
Trans shop 2owner listened to me describe the symptoms and said it is almost never the torque converter, and likey a transmission problem in the over drive gear. Recommended his own trans lube/cleaner product (a 10 oz black bottle that I don’t recall the name of), and said if it helps, it will do so pretty quickly. Also recommended against any transmission fluid change (for any car at any time, as it just causes problems). I put the 10 oz translube/cleaner and drove it for ½ hour. The shudder occurred, not quite as bad, and much less frequently (maybe 20% of the time it previously had). I went back to trans shop and arranged for a test drive.
Trans shop 2 did a test drive. Problem (shudder) did occur. Tech (supposedly 20 years experience with trans) said it could be a torque converter, or could be a trans problem, didn’t know. Returned to shop, and owner (not tech that drove the car) said again, probably not torque converter, but trans. Would recommend removing torque converter and trans, replacing torque converter ($700), and would inspect rest of transmission for problems. If transmission problem, would rebuild for $1400-$1800 (so really $1800 in my mind at least). I said thanks and left. One thing that bothered me about the tech, was that he said that the torque converter clutch could lock out of overdrive gear, and was dependent on other things. This seemed to be different to everything I had read (that the torque converter clutch only locked the engine to the transmission when the car was in overdrive.
A day later I went to mechanic. Picked this mechanic because he does transmission work, and 4 of my siblings have used him for various car repairs. One sibling was told by a different mechanic that her engine repairs would run $2000 to replace a part. Sibling came to this mechanic that there is a bad section of the part, but that the part could be separated, and fixed. Mechanic ‘fixed’ the part for $350 in parts and labor and a few thousand miles later, the car is functioning fine…
So, between trans shop #2, and mechanic, I did some internet research. Found out that there are two schools of thinking about transmission flushes.
School one: Where transmission is neglected (i.e., over 100,000 miles since transmission fluid change), a transmission fluid flush causes problems. Essentially all the detergents in the new trans fluid break loose miles of gunk/buildup (and overheated trans fluid residue) and that circulates in the trans and causes problems. So, unless fluid smells burnt, don’t change it. If the trans is not neglected, a flush probably does no harm. I don’t know exactly why trans shop #2 recommends against trans fluid changes, nor will I guess why, but there *might* be some limited support for it. I guess that it may give trans shop #2 more business later in rebuilding transmissions, but who knows…
School two: Change the fluid...
Well, I also read about torque converters, and Torque conv clutches. One site said if the shudder is occurring like in my situation (i.e., 55-60MPH), tap the brake pedal likely while on the accelerator, and if the problem stops, it could be a clutch issue…Another said in some circumstances, an engine mount could cause a shudder when certain RMS were reached. Another said to rule out wheel being out of balance (esp if the shudder gets worse as vehicle speed increases).
I considered doing a pan drop and replacing 1/3 of fluid and adding shudder guard from trans shop #1 before going to mechanic. Decided against this. First, I wanted to make sure that new trans fluid wouldn’t break loose gunk, and give me a problem. Second, I didn’t want to clean the trans pan because I thought that the mechanic would find it useful to see what was in the pan to make a diagnosis.
So, the mechanic did the trans flush and said that he’s done quite a bit with Camry’s and never had an issue about school-of-thought #1 and doing a trans flush, even on a neglected trans. He also said that there were 2 trans pan bolts missing, and other of the trans pan bolts were not really tight, leading him to think that a trans fluid change may have occurred in the past.
So, at this point, trans fluid flush/change ($200 + tax for flush, gasket, filter/screen, 1 tube shudder guard (I already had one that I gave the mechanic) and labor) and 2 two ounce shudder-guard tubes really helped the problem (and virtually eliminated it?) for now. Time will tell. I’ll try to remember to update if I find out more. In any event, it doesn't sound like the shuddering will do permamnet damage to the trans. And the mechanic said in extreme cases, if the clutch completly sticks, it could cause the car to stall. He mentioned that could put the car in neutral and rev the engine a bit shifting into gear to disengage the clutch and then drive with overdrive disengaged until the problem fixed. He said, often it will stick for much longer and then release onits own, at which time disengage overdrive, and then get problem fixed (i.e., have torque converter looked at, or the solenoid depending on where it is located).
He said that he would do nothing more at this time unless the problem gets substantially worse...
Every situation is different, and it is always best to have a mechanic/shop that you trust look at the problem so you don't possibly make a minor problem a major porblem... Mechanic also mentioned that driving the car with overdrive disengaged (and getting up to 3500 or 3600 RPMs to go 65-70MPH on the highway would not harm the car for short-term periods, but said if you did it over several thousand miles (he said 50,000-100,000 miles), it wouldn't be great for the engine.
Last edited by pb940072; 04-04-2013 at 03:26 PM.