I had my rear differential fluid changed at a local shop. I was told that the rear pinion seal was leaking and needed to be replaced ($145). The repair was made and the fluid was changed.

Now it has been about 4,500 miles and I started to get a rear end 'whine' or 'groan'. I took my truck to a different shop, who did a road test, and said that the noise is from the rear differential. I told the mechanic about the service I had and he immediately said that the shop probably over-torqued the pinion nut and crush sleeve, which has now damaged the pinion bearing and possibly the axle bearings. He also thinks the shop reused the crush sleeve after replacing the seal, which he said should have been replaced if done properly.

The shop removed the differential cover and preliminarily determined that the pinion bearing will need to be replaced, but thinks everything else is fine. He is going to get back to me about the crush sleeve tomorrow cuz they ran out of time.

The shop said that the previous mechanic is responsible for the damage and suggested that I call them and request they pay for the repairs. I am trying to get opinions about the situation to have my argument ready when I call the shop.

Is it possible that the over-torqued pinion nut and reuse of the crush sleeve could have caused this damage? Can I prove this after only 4,500 miles? What is the best way to explain this to the shop for them to understand what I'm talking about...I'm not a mechanic and am only learning about this as this goes on. Thanks!

FYI, the same shop also replaced the fuel filter that same day...broke the fuel line clip in the process...replaced the clip with one they fabricated from another vehicle. Needless to say, the clip failed...fuel line came off and I dumped a half tank of gas on the freeway...hence why I took the truck to another shop. I'm lucky to be alive from what I've been told.

 

as a ford tech i can tell you we NEVER replace the crush sleeve when just doing a pinion seal. In fact ford would probably deny the warranty claim if we did. the proper way is to mark the pinion and nut so upon reassembly you tighten untill u go just past your marks.

 

So is it gonna be tough to prove the work they did was the cause of the current problems? is there a possibility that the pinion bearing just went out with 67K miles on the truck and it's only a coincidence that the shop had just replaced the seal?

 

there is a possibility he over tightend the pinion nut but to be honest you will never be able to prove it. Pinion bearings do go bad especially the bearing cup for the inner pinion bearing. I have overhauled a few where I have found that race very pitted causing a whine. last one I did had 86000 KM which is actually pretty close to where your at.

 

I havent heard back from the mechanic yet...what should I be expecting to pay for the replacement of the pinion bearing?

what exactly does over torquing the pinion bearing and crush sleeve do that caused the damage? what wuld've been the worst that could've happened if I just continued to drive on it?

 

Mechanic called back, said the front and rear pinion bearings, pinion seal, and axle seals all need to be replaced. He said the pinion was on so tight that they had to use a wrench to turn it...apparently this should move easily by hand. He also said there was scoring to show that the pinion had been over-torqued. I know you said that the crush sleeve does not need to be replaced, but my mechanic said his shop typically replaces that when they do the seal, but the shop that did mine just re-used the old sleeve. He quoted me $770.00 to do the job.

My mechanic said he was going to document all that they found and save the parts for me...wouldn't the fact the the pinion was on so tight prove that they over-torqued it? Especially if the mechanic is willing to document that the damage was caused by the previous repair shop.

 

im am also a ford tech and i do not replace the crush sleeve when doing a seal and the pinion flange should not spin freely it will have some preload on them 20inch pounds of rolling torque not breakaway torque but spinning torque

 

the pinion should be able to turn by hand with about 20in/lbs of preload like jhunt said. If he could not turn it by hand it was definatly over tightend and wrecked the pinion bearings.

 

I talked to the service tech at Ford today and was told that Ford techs reuse the crush sleeve because Ford has a tool which allows them to keep the proper preload. As for independent shops, the tech said they probably do not own the tool and therefore should've replaced the crush sleeve.

The mechanic that did the recent repair said he is going to include an estimate of the ft/lbs of torque the previous shop tightened the pinion nut to. I'm going to give the previous shop a call tomorrow and hopefully get this $770 bill taken care of...otherwise, small claims court it is.

 

sounds like you talked to a service advisor , I can assure you there is no special tool haha. anyways good luck hope all works out for you!

 

As a matter of fact...I did! I thought he sounded like he knew what he was talking about!
Well, hopefully with the fact that the pinion nut was over torqued on there, it will be enough to hold them accountable.

The mechanic cut the bearings open and you can clearly see scoring on the metal.

Hopefully I can prove it...

 

Shop used same crush sleeve, which was correct ... but you cannot torque the nut like you would with a new sleeve being crushed and which you check in steps. Exactly.

If the shop over torques it, the sleeve is crushed more and then a new sleeve must be used and correct bearing preload re-established. You want the pinion nut replaced in the same spot exactly as it was before being removed, no looser, no tighter. The same to maintain the same preload. You do not want to crush the crush sleeve any further, just "the same" and that's only done when the nut is replaced to the same point from where it was removed.

And his term "just past" means only a hair past at most. I try to stop at the exact same point. I don't figure the pinion shaft stretches nor the bearing races compress, I figure only the sleeve will compress more if I go past it much.

Only "special tool" I can imagine is a tool which is more properly called a "yoke wrench" or "yoke holding fixture" which often attaches to the yoke with two bolts to let the mechanic pull against it while tightening the nut.

Lesson learned 35 years ago in a moment of disraction. Not a good idea to be working on the car with your GF and her 36 DDs on her 105 pound 4 foot 11 frame hanging around in her halter and "Daisy Dukes".

 

YUP! you dont want to crush the sleeve any more but it still needs to be tight enough to not come loose. I also always put blue locktite on the pinion threads before installing the nut just for peace of mind since the same nut is usually reused(it has my chisle mark on it .

 

They'll let you replace the crush sleeve if you tell them you had to reduce the bearing preload.

That said, I don't replace the crush sleeve either.

 

The mechanic estimated the torque on the pinion nut at approx 30 ft/lbs...Ford specifies 16-29 in/lbs!!! I took the repair receipt down to the previous shop. The owner said he is going to look over the paperwork and get back to me on Monday. I don't think his mechanic was in today and I'm sure he wants to see what he can use as a defense. The current shop was nice enough to document all of their findings and also saved the damaged parts.

Can you think of anyway this shop may not be held responsible...even in court if it comes to that? I only drove 4K miles since the seal was replaced and haven't had any other service on the differential since. Thanks!