Full rear axle rebuild at 95k - Grenaded after fluid change

[Drgonzo3000]

Posting my experience so others can be aware of this issue when doing the rear dif fluid change.

I had a trip planned, about 2k miles in 2 weeks, with some of it being in the mountains, Tail of the Dragon, etc. Truck just turned 95k so I decided to send it to my buddies shop for fluid changes. Trans, Transfer case, dif, brakes, etc. Truck was in great shape, no issues and regular maintenance done. First part of my trip was about 700 miles, after which I noticed a slight whine coming from the rear end. Tone changed with speed. Jacked it up and found the noise was coming from the rear dif. checked fluid and all was good. Called my buddy and he said the fluid came out clean, but noted that the rear Dif doesn't have a drain and they just use a vacuum to extract the fluid per Ford as to not have to remove the dif cover to drain and then have to reseal it. Not much I can do since I'm 11 hours from home so I continue to drive it and monitor. noise never changed and could't be heard with the AC or radio on.

Once back home I drop it off to him to take a look. popped the rear dif cover and lots of metal in the new fluid. Gear shows some signs of wear. 100% certain the noise is the pinion bearing which looks to be a common occurrence with these rear ends. But why did it decided to grenade itself after the fluid change? We are pretty sure this has to do with the bad rear dif cover design. The lack of a drain, needing to suction out fluid on the oil change and no magnetic plug all played a part.

Since there is no drain, there is no way to actually get any material/sludge off the bottom of the dif unless the cover is pulled, where as an actual drain would allow it to come out. No drain means no magnet to stop any normal wear and tear material from circulating and damaging the dif even more. Lastly, adding new fluid with the material/sludge still sitting at the bottom does nothign more that agitate it and resuspend it in the fluid which we are sure is what actually grenaded this rear dif. Basically changing the fluid causes the crap at the bottom of the dif to mix into the new fluid and tore up the dif.

So I'm looking at about $2,500 for a full rear axle rebuild now cause Ford wasn't smart enough to put a drain plug on their rear difs.

So if your coming up on fluid change, make sure they pull the cover completely off and flush out the rear dif. I'd also advise picking up a new rear dif cover that has an actual drain on it and add a magnetic drain plug to it. I'm having a Splicer cover and gasket installed when they do the rebuild on mine this week.

 

[TwizzleStix]

Sounds real suspicious to me. More like they accidently(?) put something INTO the differential, or not enough or even too much fluid rather than it just self/destructing from a fluid change, which is so unlikely to be almost impossible. Why do you mention the diff cover if it wasn’t removed for the fluid change? Was it changed out for junk earlier?

You’re paying for a new differential not because Ford, but because lazy you or your “buddy”. The whole scenario just sounds wrong to me.

 

[GCATX]

I have always pulled off the diff cover.

How much did you pay for the fluid change.

 

[Old-Raptor-guy]

Eph me!!!!
Couple of things.
As a mechanic this shit sucks. We get blamed for everything that happens after a repair.
We call it "ever since syndrome ". Two weeks ago we had a customer the we replaced rear brakes on his truck, the next day he calls the shop and say "my battery is dead this morning, what did you do to my truck".

Battery was 5 years old, took alot of talking to somewhat convince him it wasn't anything we did.

It is possible that the pinion bearing was going to fail in 700 miles no matter what service was done. Heck changing the oil every 30k may not prevent this sort of thing.

I have seen differentials go 600k and I have seen them fail at 30k.

With all that, the diff cover should be removed for a service.

As far as Ford not being smart enough to have a drain. 95% of all differentials built in the last 50 years do not have a drain.

Like someone else said, your buddy got lazy. His lazy service (I am going to check service manual and report back) gave him a black eye and he is trying to deflect the problem to Ford engineering.

 

[thatJeepguy]

I think all in I spent:

100 for dana spicer cover on marketplace
20 for lube locker gasket
80 for amsoil severe gear

Service took 30 min.

 

[thatJeepguy]

Eph me!!!!
Couple of things.
As a mechanic this shit sucks. We get blamed for everything that happens after a repair.
We can it "ever since syndrome ". Two weeks ago we had a customer the we replaced rear brakes on his truck, the next day he calls the shop and say "my battery is dead this morning, what did you do to my truck".

Battery was 5 years old, took alot of talking to somewhat convince him it wasn't anything we did.

It is possible that the pinion bearing was going to fail in 700 miles no matter what service was done. Heck changing the oil ever 30k may not prevent this sort of thing.

I have seen differentials go 600k and I have seen them fail at 30k.

With all that, the diff cover should be removed for a service.

As far as Ford not being smart enough to have a drain. 95% of all differentials built in the last 50 years do not have a drain.

Like someone else said, your buddy got lazy. His lazy service (I am going to check service manual and report back) gave him a black eye and he is trying to deflect the problem to Ford engineering.

I agree with this 100%

If a pinion bearing is going bad or the shim stack on the carrier is off by just a couple .001’s its going to fail no matter how much lube or how often you change.

 

[nikhsub1]

Could just be coincidental too - F150s are known for having the pinion bearing to go t!its up for just no reason at all... I'm going with occam's razor on this one.

 

[Old-Raptor-guy]

Well your friend did follow the service manual it appears. So Ford has gotten lazy. I don't see how you can lay any of this on your friend. (Although we remove and reseal diff covers on our services).

My money says that pinion bearing was going to fail regardless.

 

[Old-Raptor-guy]

Lastly, 95% of the time the ring and pinion gears can be reused on a pinion bearing failure. Although we did just have a Ram pickup that required a new gear set.

 

[Drgonzo3000]

Eph me!!!!
Couple of things.
As a mechanic this shit sucks. We get blamed for everything that happens after a repair.
We call it "ever since syndrome ". Two weeks ago we had a customer the we replaced rear brakes on his truck, the next day he calls the shop and say "my battery is dead this morning, what did you do to my truck".

Battery was 5 years old, took alot of talking to somewhat convince him it wasn't anything we did.

It is possible that the pinion bearing was going to fail in 700 miles no matter what service was done. Heck changing the oil every 30k may not prevent this sort of thing.

I have seen differentials go 600k and I have seen them fail at 30k.

With all that, the diff cover should be removed for a service.

As far as Ford not being smart enough to have a drain. 95% of all differentials built in the last 50 years do not have a drain.

Like someone else said, your buddy got lazy. His lazy service (I am going to check service manual and report back) gave him a black eye and he is trying to deflect the problem to Ford engineering.

As you pointed out, the manual was followed and yes Ford and every other manufacturer have gotten lazy. They don't care about proper maintenance, 10k oil changes and 150k mile drivetrain fluid changes, Yep they know exactly how to market stupid people into following it and their vehicles not making it past 100k, then they go buy a new vehicle.

I don't blame this on my friend at all, I never said I did, I sent this to his shop as I know 1000% he won't BS me. He does what he is supposed to do and follows the manual.

As for th shim/crush, Backlash was checked and was within Ford manual spec.

Yes, premature pinion bearing failure is common on the Ford 9.75 rear ends. I'd like to know how many of them occur not long after a fluid change, especially when following Fords manual.

My Friend is not doing the rear end rebuild, He said there are some special tools required to set the backlash properly that he doesn't own. So the Truck is going to a Drivetrain Specialty shop to be rebuilt. The quote of $2200 was for a full rebuild, ring, pinion, bearings, seals, etc. Mostly likely the pinion and ring will be reused, they just haven't personally seen it yet to make the call.