Finished Rear Diff Rebuild

[Dave8338]

I'm happy to report that the rear differential on my Explorer is now quiet and vibration free. What I found when taking it apart:

1) Pinion bearing / race severely pitted and completely shot.

2) Inner axle bearing on passenger side SHOT.

3) Drivers side wheel bearing rough and pitted.

4) Ring and pinion gears worn beyond their service limit and then some.

5) Spider gears and gear pin well worn with the pin having a wear ridge that I could feel with my finger... not good.

What I did:

Replace EVERYTHING !

I reused all of the original shims and checked the mesh pattern of the R & P after things were reassembled and was happy with the wear pattern. Under load, the pattern was "heal to toe" wear and under back pressure (deceleration) it is toe to heal mesh. Meaning that the gears will continue to wear to the center of each other, which is what you want.

Rock auto came through with a VERY HIGH quality Master Rebuild Kit and the only additional parts that I ordered were the wheel hubs and bearings and a Fel Pro cover gasket. The hardest part of the whole project was cutting through the pinion bearing to retrieve the original shim and holding the pumpkin still/tight while setting the pre-load on the crush sleeve. Kevin (good friend and Ford Certified tech) made the job look easy. It was a good lesson for me in how the 8.8 IRS rear end is build and what is needed to completely rebuild one of these little monsters. Really... not that difficult but a press is needed and the spindle / wheel bearings are a royal PITA .

Happy to have a quiet Explorer. First time in the last 100,000 miles. Truck just rolled over 236,x.. last weekend.

 

[imp]

Good Post!

Not everyone would tackle your job. How in the world did you live with all those different bearings making noise all at once?

Did you replace the ring & pinion, not clear on that. The wear you describe inside the differential itself is somewhat unusual, but the pinion bearing failed was not. Pinion bearings being under considerable preload, generate lots of heat, helping to lead to their own destruction. You were aware that the preload is very important.

You have no idea how many guys have removed yoke to get at leaking seal, then close up with no clue of preload, if any. Often the nut gets tightened only until drag is felt, the crush washer (old) is not exerting any force on the assembly, and the nut loosens soon in service. Congratulations! imp

 

[Dave8338]

Not everyone would tackle your job. How in the world did you live with all those different bearings making noise all at once?

1) Did you replace the ring & pinion, not clear on that. The wear you describe inside the differential itself is somewhat unusual, but the pinion bearing failed was not. Pinion bearings being under considerable preload, generate lots of heat, helping to lead to their own destruction. 2) You were aware that the preload is very important.

You have no idea how many guys have removed yoke to get at leaking seal, then close up with no clue of preload, if any. Often the nut gets tightened only until drag is felt, the crush washer (old) is not exerting any force on the assembly, and the nut loosens soon in service. Congratulations! imp

1) IMP... the ring and pinion were both replaced. I went with a matched set of 3:55 Richmond gears, for that. 2) Sure was/am. Measured in inch pounds.

The noise has been there for 100,000 miles and even though I've done the wheel bearings, the rear diff has an all together different sound, as I'm sure you are aware of. It wasn't until the last 7-10K miles that I KNEW I was getting close to its' max service life. Under deceleration, the backlash would reverberate through the drive shaft and into the transfer case. When you can FEEL the R&P under your feet, it is PAST time to do something about it.

All said and done, the complete rebuild cost me less than $ 700.00 including all parts and $ 300.00 to Kevin for his time and patience in working with me.

 

[imp]

Dave, good job! You're fortunate to have the abilities you do.

I "cut my teeth" on Ford 9-inchers back when I was a teenager. By early adulthood I had quite a collection of center-sections, all set up, awaiting use. One of my moves, unfortunately, did not allow dragging them along, and behind they were left. If you ever want info not findable on the Net about Ford's 9", give me a holler! They used 4-pinion differentials in taxicabs and police cars; those are strong! imp

 

[esclamada]

1) IMP... the ring and pinion were both replaced. I went with a matched set of 3:55 Richmond gears, for that. 2) Sure was/am. Measured in inch pounds.

The noise has been there for 100,000 miles and even though I've done the wheel bearings, the rear diff has an all together different sound, as I'm sure you are aware of. It wasn't until the last 7-10K miles that I KNEW I was getting close to its' max service life. Under deceleration, the backlash would reverberate through the drive shaft and into the transfer case. When you can FEEL the R&P under your feet, it is PAST time to do something about it.

All said and done, the complete rebuild cost me less than $ 700.00 including all parts and $ 300.00 to Kevin for his time and patience in working with me.

Do you think this could be a DIY job without some special tools? differential spreader and pinion depth gauge. Just to confirm the parts are close to $400?



-----------------------------------------------------------
MY MOUNTY
http://www.facebook.com/diyfordexplorer/photos_albums

 

[imp]

Do you think this could be a DIY job without some special tools? differential spreader and pinion depth gauge. Just to confirm the parts are close to $400?



-----------------------------------------------------------
MY MOUNTY
http://www.facebook.com/diyfordexplorer/photos_albums

The years ago Dana center sections found in so wide a variety of vehicles, (Ford, GM, Chrysler, Jeep, Volvo, etc.) were well-known to every type of mechanic. The last guy I saw pull out a diff/ring gear pried it out with a crowbar! Case spreader? You're kidding! imp

 

[Dave8338]

Do you think this could be a DIY job without some special tools? differential spreader and pinion depth gauge. Just to confirm the parts are close to $400?



-----------------------------------------------------------
MY MOUNTY
http://www.facebook.com/diyfordexplorer/photos_albums

Yes, it can be a DIY job as long as you have a few tools and take the time to do it correctly. I didn't need a case spreader to get things apart. Putting it back together, required a homemade spreader (a couple of bolts, welded to a pair of nuts and some all thread) to be used. Ford made the cases just tight enough that in order to get spiders in, the housing needed about an additional 1/16" spread. Without it, the spider assembly would bind and things wouldn't go.

YES... parts ran about $400.00

Though the kit came with several shims, I was told to use the original shims and it would all go back together the way it came apart. It did.

 

[esclamada]

Yes, it can be a DIY job as long as you have a few tools and take the time to do it correctly. I didn't need a case spreader to get things apart. Putting it back together, required a homemade spreader (a couple of bolts, welded to a pair of nuts and some all thread) to be used. Ford made the cases just tight enough that in order to get spiders in, the housing needed about an additional 1/16" spread. Without it, the spider assembly would bind and things wouldn't go.

YES... parts ran about $400.00

Though the kit came with several shims, I was told to use the original shims and it would all go back together the way it came apart. It did.

Thanks, I was really in doubt about the usage of the tool, but you got me convinced to just improvise. There were cases that removing the carrier is tough on these aluminum pumpkin. Not sure if I want to tackle this, the differential whine is tolerable at the moment. I could hear the whine when decelerating, it's either I'll wait till it explode or a decent used one is available in craigslist.



-----------------------------------------------------------
MY MOUNTY
http://www.facebook.com/diyfordexplorer/photos_albums

 

[Dave8338]

Thanks, I was really in doubt about the usage of the tool, but you got me convinced to just improvise. There were cases that removing the carrier is tough on these aluminum pumpkin. Not sure if I want to tackle this, the differential whine is tolerable at the moment. I could hear the whine when decelerating, it's either I'll wait till it explode or a decent used one is available in craigslist.



-----------------------------------------------------------
MY MOUNTY
http://www.facebook.com/diyfordexplorer/photos_albums

From my experience, when dealing with a known problem spot on a machine, where MOST if not nearly all have the exact same problem, I choose to rebuild things. A used one is likely to suffer the same conditions that you already have. You'll be out the money AND time and have to do it twice.