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GurthBrooks 05-05-2014 03:26 AM

Had 4:10 now 3:73 still same problem
Hello, I own a 2001 GT with a automatic. 2yrs ago I had 4:10's put in to the car along with all new bearings, seals, rebuilt the limited slip, new drive shaft and u joints, 6months later the car had a bad vibration and loud noise just like you drove over rumble strips on the freeway you could feel it in the seat while driving. This occurs anytime while driving, does not stop when put in neutral. One shop told me it was because the gears where not shimmed correctly. Solution put a new set of gears in with all new bearings and seals. Again still the same problem. Changed rear tires still same. With something so loud with this much vibration is it possible its not the rear end Taking car back into yet another shop to have them look at it. Sorry so long!!! thanks for any help.

edwin108 05-05-2014 03:42 PM

Maybe your driveshaft is unbalanced?

[email protected] 05-05-2014 04:33 PM

So it's any time the car is moving? I'd second the driveshaft balance as a possibility.

Any clunks when putting it in gear?


drewsky 05-05-2014 07:01 PM

I will third on the driveshaft.. Does it only happen at certain speeds, or all speeds?

GurthBrooks 05-06-2014 01:00 PM

Sorry forgot to mention the drive shaft is also new with new U joints

Simon1 05-06-2014 02:45 PM

If the rear end was the only thing work on prior to the problem, that's where I would look.

However, six months after install the problems start, it really could be anything.

I would get it on a lift and put in gear to let someone listen and locate where the noise comes from.

Drive shafts can loose weights also. You could look at the drive shaft and see.

JCON 05-07-2014 04:28 PM

Has anyone checked your tire balance?

tx_zstang 05-13-2014 02:45 AM

Not likely the rear end. Your symptoms are usually the result of a unbalanced tire or driveshaft. Could also be due to pinion angle.
If you have a 4r70 as your automatic, it could also be the brass bushing in the tailshaft housing where the driveshaft slips into, being worn out.

But if it is that bad, you should be able to raise the rear of the car, put jackstands under the axle to hold it up (safely of course), but it in neutral, and turn the driveshaft by hand, feeling for clunking or binding. Usually if it is that bad of something, you'll feel it.

If it is only at certain speeds, it'd be more of a balancing issue.

GurthBrooks 05-14-2014 04:35 AM

Thanks to everyone who gave their input. I was told that the reason for the vibration and sound is from installing (Ford Racing gears) two separate shops told me this. I was told they are known to be very noisy and have a vibration. Both sets that I have used were Ford Racing 4:10 and now 3:73. Im having a hard time believing that Ford Racing gears could be the reason. Has anyone ever heard of this?

johnny_raincloud 05-14-2014 02:21 PM

I have heard of that happening when the gears are installed incorrectly by idiots! I have driven a few S197's with both gears and never felt or heard anything unusual...

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