1995 Ford Mustang Pinion Bearing Failure

Tiny
JAMES PAUL
  • MEMBER
  • 1995 FORD MUSTANG
  • V8
  • FWD
  • MANUAL
  • 30,000 MILES
This car has been driven sparingly over the last 15 years. Last year I took it to a local Ford repair shop known for specializing in blue oval products because of real axle noises. This wasn't the first time, I had problems with the rear end when it was brand new which resulted in the dealer replacing the entire axle assembly. Fast forward to last year and the shop found the pinion bearings to be absolutely trashed. New pinion bearings were installed (used the ring and pinion and carrier bearings) new fluids, etc. Back lash reset. It sounded great though there was a minisule whine. Two weeks ago with a vengence, the noise comes back after only 4k miles from less than 1 year ago. Took it back. Pinion bearings trashed once again. Shop claims it was setup perfectly but is replacing ring and pinion and all bearings with Ford parts. Measurements all look good. Any ideas what's going on?
Thursday, September 17th, 2009 AT 12:31 PM

7 Replies

Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
OK so tell me what rear end do you have the 7.5 or the 8.8? I must know how do you drive a Mustang and not play with it? I play with mine. Also have the u-joints been checked? Do you feel any vibration at highway speeds? Get back to me with what you can and we will take it from there.
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Friday, September 18th, 2009 AT 9:33 AM
Tiny
JAMES PAUL
  • MEMBER
  • 4 POSTS
It's an 8.8. It used to be a play car but it's a daily car now, I like to drive it hard, it's a Cobra. But I think you mis-understood the question. Can you think of any reason why the pinion bearings keep failing on this car? I just picked it up this morning from the repair shop and for the second time discussed with the mechanic how in the devil the pinion front and rear bearings end up being totally galled after 4000 miles in 11 months. I trust the mechanic, Fords are his speciality, I trust him when he says everything is in spec. This time all the bearings were replaced, including the ring gear. Could the machining on the housing been bad and the relationship? Since there aren't any other vibrations, the driveshaft hasn't been suspect. I could see how a problem there might aggrevate the issue, but. Ya' think?
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Friday, September 18th, 2009 AT 9:55 AM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Ok so tell me what gear oil is being used. See I worked for Tom's Diff so I do know something about rear ends and I am also a Cert. Mechanic and a Ford die hard. My Mustang is a 98 with a 3.8lt V-6 with an 11psi pro charger pushing 500 hp. Anyway get back to me with the gear oil being used I am thinking with the car being what it is that they are not using the right gear oil to hold up to playing and some hard launching. I recomend using Lucas 75w140 with a 20% mix of Lucas oil stabilizer. This will hold up to some abuse and keep the bearing well lubed too. Get back to me.
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Friday, September 18th, 2009 AT 10:33 AM
Tiny
JAMES PAUL
  • MEMBER
  • 4 POSTS
Motorcraft oil and friction modifier. Standard spec stuff right off of the dealer's shelf.
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Friday, September 18th, 2009 AT 12:41 PM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Believe me it isn't good enough especially with a car that is played with. If the oil is synthetic then even worse on hard launched as synthetic can be swished out during hard launches which can leave bearings and ring and pinion dry for a moment. What you are discribing as far as how the bearings look is from lack of lubrication. I am giving you my opinion from what you tell as to what will help and hopefully keep you from having to replace bearing again. Like I said I worked for a Diff shop and we sold mostly to Pro Mod runners, Nascar and Drag racers so I know what I am saying. I am not saying that the dealer did anything wrong except they only deal with stock situations. Let face it your car is a Cobra with some power so I doubt you drive it like you would a Geo that has no power I know I don't. I am just saying that you should change you gear oil very simple thing to do and if nothing else you might not be replacing bearing again. Let me know how things go.
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Saturday, September 19th, 2009 AT 9:24 AM
Tiny
JAMES PAUL
  • MEMBER
  • 4 POSTS
One thing I do DO is while I don't wing it up to 5grand and then dump the clutch, I often love to punch the crap out of it in 1st gear. Love the 5.0 torque. You might have a point. It is a simple solution. I'll go try it. Do you still use the Ford friction modifier?
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Saturday, September 19th, 2009 AT 12:18 PM
Tiny
RACEFAN966
  • MECHANIC
  • 5,029 POSTS
Yes you can, Lucas has fiction modifier in it but it won't hurt to put fords in it too. You shouldn't hear any noises or anything coming from rear anymore. I did't think that you launch it like 5 grand or anything but I know I leave a stoplight with a little rubber left behind when challanged by a ricer. I know that synthetic oils don't like this much so that is why I recommend a change in oil. Also you said that the bearings were all discolored and gaulded which indicates lack of lubrication to the bearings. So it just makes sense that it is the fluid. Let me know how it goes.
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Monday, September 21st, 2009 AT 4:20 PM

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