Need Help with Rear End Issue.

[M3xpress]

I can't figure out what is causing a problem in my drivetrain.

In low gear, crawling speeds like moving about a parking lot I'm getting a noticeable knocking sound, and its really apparent at these speeds when turning. When turning the wheel back and forth or turning in general from a dead stop or crawling you can feel a drag on the car.

From red light to red light, increasing speeds, etc., it seems to be normal.

The only thing different is I'm getting a louder whine when I accelerate.

The rear end was checked out a couple months ago and nothing stood out as being wrong.

I've heard it might be a bad ujoint, but I would've thought that would be a problem on the interstate.

I've also heard that it could be a bad input shaft bearing.

Carrier, diff? I don't know, I just want to pinpoint it and fix it.

 

[trinity_gt]

Sounds like you've got issues with both the limited slip (the binding/knocking when turning) and a possible rear pinion bearing issue (the whine under acceleration.)

It's probably time for a rebuild: new bearings, new clutches etc.

What's the history of the rear? How many miles? Any previous work done to it (e.g. gears)? Fluid changed?

 

[flstang65]

^
What he said. Also, if you do need to do a rebuild, might as well put some gears since you will have the rear end apart.

Lol, when I first saw the thread title I was getting ready to tell you to not eat so much Mexican food. Ok, I'm bored at work.

 

[COramprat]

I'll give you my experiences with different issues I've had and see if that helps.

U-joint...Started as a "moan" in 4th and 5th around 2500 RPMs. Sounds like a subwoofer with a steady tone. It got increasingly worse over time and would happen in all gears...but at the sam general RPM range.

Pinion bearing...Noticable sound that incresed with speed...sort of a "whoomp whoomp whoomp" as you accelerated.

Rear wheel bearing...Similar to the pinion noise but was more noticable on the drivers side of the car. After a while it was more of a grinding noise. The drivers side bearing was shot and had eaten into the axle shaft.

The carrier bearing could be an issue (I think that is a problem with mine now) but I don't know for sure since I haven't checked it out closely but if i had to guess on yours it would be a rear wheel bearing. It doesn't sound like the u-joint is the issue.

 

[calboss281]

This sounds exactly like my problem that I posted last week. The above guys are right, you need a rebuild. If you're around 50,000 miles thats about the same as me.

I bought the Ford Racing Rebuild kit and some new gears to install while I have the case open.

Don't take it to a dealor..they'll just charge you 100 bucks to confirm what we have told you. If your car makes grinding noises from the rear end during slow turns it means your clutchpack is worn out.

Also, don't buy the parts from the web!!! Buy them from an authorized Ford Racing dealer. On the web the rebuild kit goes for 100-130. I got it for 90 bucks from Ford.

 

[M3xpress]

As far as drivetrain mods other than an aftermarket clutch, the car has an alum ds and gears.

The fluid has been changed recently, and when the diff cover was off there didn't seem to be anything that jumped out as being wrong. That's why I thought it might be something small like a bearing.

I initial thought it might be a wheel bearing, but there doesn't seem to be any play in the wheels when they are in the air.

The car doesn't really grind, you can just feel the reisistance when turning at slow speeds.

So is that my best option is to go with a rebuild kit and see if that corrects the problem?

What all does it come with and I should just order it straight from a dealer?

 

[calboss281]

The car doesn't really grind, you can just feel the reisistance when turning at slow speeds.

So is that my best option is to go with a rebuild kit and see if that corrects the problem?

What all does it come with and I should just order it straight from a dealer?

Well mine didn't grind at first either. It just felt some resistance and some sluggishness during slow speed turns 5-25mph. I however never got it fixed because I thought it was rubbing but now I know that's not the issue at all. I'm imagining that you just noticed the problem sooner than I did.

Your best option is to just call up a dealer right now and order the parts (provided you don't pay more than 380 for the parts).

 

[M3xpress]

So after the rebuild kit you were good as new? No issues? $90?

 

[calboss281]

hah, I haven't gotten to work done yet man. I JUST had this problem diagnosed last week (as I stated). I have the parts, I'm just shopping around for a good shop to do the work. But according to the guys on this forum, and the Ford Dealer...this is what the car needs...and this is what will fix it.

Some guys on another forum suggested to upgrade the limited slip differential while working on it....because it'll add another 50k to the car's life...but I'll just replace it when the car gets older.

 

[calboss281]

Also there was a member on this forum who diagnosed my problem because he had dealt with it a year ago. I don't remember his name....

...but he said that the dealer did a full rebuild and install for 700 something bucks...and it fixed the problem. But I doubt he NEEDED to pay that much. A rebuild should cost less than 200 I imagine.

 

[crazystang25]

actually rebuilds can get a little expensive if they have to get in there and start tearin the diff. down and taken gears out. cost me $800 to have my 9 in. put in and all they had to do is put the axles in and the housing on there. then just bolt it up only exception is a plate they had to have fab'd for the brakes. that cost about $90. and 1330-1350 u-joint($60). so to put it in cost about $650.