Drivetrain shudder

[76L82]

I know this issue has been beat to death..but you guys offered some great advice to me a while ago and my problem has been solved. Hopefully this will help someone as your advice did for me.

Have a 2000 XLS auto. with 70K miles, automatic 4wd and never taken off road too seriously. Out of the blue this thing starts to develop a MEAN shudder when taking off from a stop or driving between 15 and 30 miles per hour. Had the brakes all done, new calipers on the rear, had the wheel bearings looked at...nothing. Had the tranny flushed along with the transfer case..and the problem persisted. Frankly, I was ready to get rid of it although it has been a flawless vehicle up to this point. However, this shudder was killing me and I had brought it to just about every dealer in the State to no avail.

I bring it to one of the last dealerships and the service manager, who was just starting his first job there as a first time service manager, says "oh yeah..that is clearly a tire problem". Say what?? I reply. He goes on to show me that the inside ridge of the tread on both front tires are worn down considerably more than the other tread on the tires. In fact, if he didn't point this out to me I would have barely thought it to be an issue at all.

He goes on to tell me that the "sensors"...never quite sure EXACTLY what that means...in the four wheel drive system are picking up a reading that the front tires, due to the wear of the tires, are moving at a different revolution than the rear tires. Essentially they are picking up a form of "slippage" and it is periodically kicking in 4 wheel drive. I tell him that this is the most ridiculous thing I have ever heard...right up there with you need to replace the "canuta valve" or the "johnson rod". This would suggest that a partially worn tire can render a $30 SUV useless? Never heard something so ludicrous.

Having done just about everything else...I buy 4 new Kumho tires (real pleased with these by the way), get an alignment....and here is the kicker...the darn thing has not shuddered 1 single bit!! Being the man that I am...I call the service manager up the next day and tell him he was 100% right on the money!

Talk about one for the record

 

[jsun]

Originally posted by 76L82
I know this issue has been beat to death..but you guys offered some great advice to me a while ago and my problem has been solved. Hopefully this will help someone as your advice did for me.

Have a 2000 XLS auto. with 70K miles, automatic 4wd and never taken off road too seriously. Out of the blue this thing starts to develop a MEAN shudder when taking off from a stop or driving between 15 and 30 miles per hour. Had the brakes all done, new calipers on the rear, had the wheel bearings looked at...nothing. Had the tranny flushed along with the transfer case..and the problem persisted. Frankly, I was ready to get rid of it although it has been a flawless vehicle up to this point. However, this shudder was killing me and I had brought it to just about every dealer in the State to no avail.

I bring it to one of the last dealerships and the service manager, who was just starting his first job there as a first time service manager, says "oh yeah..that is clearly a tire problem". Say what?? I reply. He goes on to show me that the inside ridge of the tread on both front tires are worn down considerably more than the other tread on the tires. In fact, if he didn't point this out to me I would have barely thought it to be an issue at all.

He goes on to tell me that the "sensors"...never quite sure EXACTLY what that means...in the four wheel drive system are picking up a reading that the front tires, due to the wear of the tires, are moving at a different revolution than the rear tires. Essentially they are picking up a form of "slippage" and it is periodically kicking in 4 wheel drive. I tell him that this is the most ridiculous thing I have ever heard...right up there with you need to replace the "canuta valve" or the "johnson rod". This would suggest that a partially worn tire can render a $30 SUV useless? Never heard something so ludicrous.

Having done just about everything else...I buy 4 new Kumho tires (real pleased with these by the way), get an alignment....and here is the kicker...the darn thing has not shuddered 1 single bit!! Being the man that I am...I call the service manager up the next day and tell him he was 100% right on the money!

Talk about one for the record

Glad to hear things have fixed for you and your thoughts about your X.

I appreciate when peeps post back with their results for better use of browsing the search tool.

I would just question why the tires wore out of tread around the insides to begin. Slapping new tires maybe a short term fix until there out of tread again. Understanding that an alignment has taken place and was also related.

I'm not saying theres more wrong to this...I'm just ensuring that nothing was missed to prevent re-occurance...

Cheers!

J

 

[dogfriend]

Originally posted by 76L82


He goes on to tell me that the "sensors"...never quite sure EXACTLY what that means...in the four wheel drive system are picking up a reading that the front tires, due to the wear of the tires, are moving at a different revolution than the rear tires. Essentially they are picking up a form of "slippage" and it is periodically kicking in 4 wheel drive. I tell him that this is the most ridiculous thing I have ever heard...right up there with you need to replace the "canuta valve" or the "johnson rod". This would suggest that a partially worn tire can render a $30 SUV useless? Never heard something so ludicrous.

Having done just about everything else...I buy 4 new Kumho tires (real pleased with these by the way), get an alignment....and here is the kicker...the darn thing has not shuddered 1 single bit!! Being the man that I am...I call the service manager up the next day and tell him he was 100% right on the money!

Talk about one for the record

He was talking about the driveshaft speed sensors which are mounted in the transfer case. They monitor the speed of the front and rear driveshafts and feed this information back to the GEM (generic electronic module - i.e. the computer that controls the engagement of the auto 4wd function). If one of the driveshafts is rotating slower than the other (usually it would be the front) the GEM interprets this as the rear wheels slipping and engages the transfer case clutch to send more torque to the front driveshaft.

The only thing I see that is strange in your case is that the wear is on the inside edge of the tires - on mine, the outside edge is the one that is wearing more quickly. If they adjusted the camber, it should correct this problem.

Did you get 70K from the original tires? Probably not because of the Firestone recall. I got 52k from the rock hard Wilderness ATs, I have 40k on the replacement GY Wrangler RT/Ss, but now all four have a feathered wear pattern on the outside edge, so I will have to replace them before the tread is worn out

 

[76L82]

Thanks for the help deciphering this one. I wasn't real sure EXACTLY how this got solved.

Good point about the odd wear pattern...I did get an alignment...was told that the X didn't get all 4 wheels aligned so I just got the front aligned I believe.

Oh, I truly love this vehicle. It is actually my wifes and she never let's me touch it...therefore, I have been 'relegated' to an old Corvette as a daily driver. As a result, I have never gotten real acquainted with the X. To tell you the truth, that thing has been flawless since we have had it....and the good folks at Ford bought us brand new tires every 15k miles for the first 2 years we owned it