Hello,
I have a 2006 F150 with a bad whine coming from the rear end. Seems to happen over 30 mph and is consistent, even when I speed up or slow down. Run on jack stands to listen, seems to be coming from pinion area. Pulled the drain plug and all kinds of metal junk on it. Pulled cover to check gears, them seem to be good yet. Does it make sense to replace the pinion bearings or the whole rear end? I'm thinking I should be able to reuse shims and just replace bearings and set preload, shouldn't have to worry about gear setup. Let me know your thoughts...

 

In order to replace both pinion bearings, the whole thing has to be disassembled so you may as well replace all of the bearings. The backlash needs to be measured to make sure it is correct, but yes the shims should be the same. My one experience with crushing the pinion bearing load spacer was on a 74 Ford Stationwagon and it took a tremendous amount of torque to start crushing the sleeve, something I'd guess at about 400 ft lbs. And to measure the proper preload on the pinion bearings the carrier part needs to be out. I've done this sort of thing in the past successfully but it's probably best left to the pros. I was lucky because I didn't have a dial indicator or an in. lb. torque wrench.

 

Yes, leave this stuff to the pros.

I also recommend Richmond gears... they cost a little more, but they will outlast the truck.

 

Thanks for the reply...

I did check with the local service garages [Pros] that claim they do differentials, but sounds like they would rather swap the rear end out with used, at a cost of $700-800. If they were to dig into the diff, would start around a $1000 and go up from there.

Wasn't aware the crush sleeve took that kind of torque to crush, that's a big breaker bar!!!

I would like to understand how to work on differentials for the experience to use on future projects. What about the thought of reusing the crush sleeve and shims, count the threads on the pinion nut, and take an initial preload torque, and use that as a reference. Also I would replace any other bad bearings I find on carrier and axles. If that doesn't work, then I would swap out the rear end for a used one. I'm thinking it's worth throwing $50 worth of bearings and seals at it to save some money and get experience. If it doesn't work, I throw another $300-400 worth of used rear end and it to get it going. My thought, may not be right...

 

I would do some shopping around. It sounds like those [Pros] high balled it. Some do that to not want you to have them do it OR they will take your truck else where to have it done and charge you for it.

I suppose the next questions are: How many miles are on the truck? Are you planning on keeping it for a while? Engine?

If you answered around 100k, and yes, 4.2l OR 4.6l. Then I'd find a competent shop that works only on transmissions and axles. I would then buy the Richmond gear set and have them install it.

 

Watch some videos on utube about diff rebuilds to educate yourself before attempting it. There should be lots of them out there. I've watched a few myself.

When I thought I may have a bad pinion bearing in my 02, I contacted a local 4x4 shop and they said they would rebuild it no matter what was wrong with it for $600. So, I suggest you find a 4x4 shop. They change gears often and should know what they are doing. Regular garages don't do it that often.

 

Thanks Roadie,
I'll do some checking around and more research.

 

I stumbled onto this series of videos on how to rebuild a Ford 9.75" rear. They are long but if you watch them you will learn a lot about how to repair a rear diff.

 

Roadie,
Thanks for the link, I did see this one and many others. I have enough information that I feel confident in going after this. Also had pick up some tools needed to do this job, one being the pinion flange holding tool. Based on all the videos and reading I did, sounds like with replacing pinion bearings you really need to replace the crush sleeve. And as you said before, this requires some serious torque to get the job done. I have an inch pound beam wrench for reading preload, so I should be good with that. I think I only need a bearing splitter now, which I don't think the parts store offered on loan. So I'm hoping just to replace bearings on pinion, possible carrier and any related seals on the axle and be done. The gears weren't the best, but I don't think they were causing of this being the noise is constant with speed, didn't matter with load or accelerating. If it points to gears, I'm confident on that also. I understand the patterns, pinion depth and preload, and backlash. I figure I'll get some extra tools and experience from this, worst case I replace the rear end if this fights me.
Thanks for your feedback, it has been a big help....

 

Roadie,
Pulled the differential apart today and it looks like pinion bearings are bad. All other bearing and races didn't look bad, so I'm thinking of just replacing the pinion bearings and setup. Once I had the carrier out and could spin the pinion, it felt like it was crunching to the point it didn't pay to check preload for a reference. Pinion didn't show much wear on it. Just waiting on parts now...

Inner cup

Inner cone

Outer Cone

Outer Cup

 

Yes, those bearings appear to need replacement. Do you have the tool that holds the pinion in place while you crush the sleeve? Even using the old shims on the carrier, you probably need to check the backlash with a dial indicator.

 

Yup, ordered the pinion flange holder online along with the magnetic dial indicator for backlash. I forgot to check the backlash before I pulled it, but it didn't feel excessive when I checked by hand. But will check when I put back together. That's why I like to do these jobs myself, good experience and I get more tools. Hoping my 1/2" breaker bar with a pipe will be enough force to compress the crush sleeve. If not, I'll have to pickup a 3/4" breaker bar. Checked local dealerships for the bearings I need, none had the inner, so after the holidays I'll keep checking dealerships further out for this bearing. Local parts stores wanted more than the dealership, and was a factory order which would take like 5 days and I wasn't sure I would get the correct bearings. Sounded like these kind of parts was out of their wheel-house, good for brakes and u-joints not these...

 

Roadie,
I should also mention that I noticed the diff was leaking at the pinion not and not at a seal which is part of the reason these bearing failed. I did have a add a pint a few weeks back and didn't see any leaking which was weird. But when I went back under to start work, I noticed the nut and rear u-joint was wet. So most likely going to need to replace the flange also.

 

When the pinion bearings go bad, it gets very hot causing the lube leaks. What alerted me on my old 74 wagon way back when besides the noise that sounded like a bad tire to me was a leak at the axle seal. On my old 74, only the outer pinion bearing was bad, but I disassembled the entire rear and replaced both pinion bearings. Sounds like you have it under control. Good Luck! And let us know how it turns out.

 

Roadie,
Looks like it was mainly the inner pinion bearing that came apart. I was able to get a pinion kit with carrier bearing for $150 online. Took a few days to deliver, so I replaced the wheel bearings and u-joints while I was waiting. Your right about the pinion bearing, real pain to set preload, took me a few times and a couple crush sleeves to get it right. It all worked out with using the same shims, no need to go through a setup of the gears. Took the truck for a test drive, no leaks and no hot bearings, so good to go. Really wasn't too bad, setting the preload of the pinion and the u-joints were the worst of it. Attached is the inner pinion bearing cone, showing where all the metal came from. Thanks for the help!