differential insurance

[frankendat]

In my feeble mind, the best option for refurbishing differentials (in this case meaning the entire axle assembly sans brakes) would be to remove the differential axles and bearings, clean/coat the interior and exterior of the axle tubes and center housing, install new bearings/seals and reinstall differential gears (if they meet SDS) However, when I attempted this strategy on a non-Nissan differential, the cost of reinstalling differential gears (which requires a shop) sunk my plans.

All other steps can be accomplished by someone sort of handy with a handful of tools. Bearings press in, but you can make it happen, tubes can be checked for true with some basic geometry, but shimming and reinstalling the main gears gets beyond me quickly.

Is there a second best option, which I am unaware? Even doing all the cleaning and the coating myself it would be over $1k (closer to 1.5K) to "refurbish" a front and rear axle/diff on a 720 4wd and that's keeping stock internals.

Looking for ideas. I hate putting old parts next to new parts (or newly refurbished parts) because it seems an obvious weak link and I will have no one to blame but myself if stranded because the old part snaps.

[Stoffregen Motorsports]

First off, you don't need a shop, or any special tools, to rebuild a diff or axle assembly. They only part on an axle that may require a special tool is the bearings pressed onto the axle shaft. Many times, the shaft bearings have a collar that holds them in place, and this is where homeowners get stumped. The simple solution is to drill them and chisel them until they split. Takes about 5 minutes per side.

 

I'm curious why you think a shop has to dot he reassembly? Most times the differential bearings don't need replacing. And even if they do, you can knock them out with a hard metal drift (I use a solid 1/2" steel rod). Installing new bearings is easy with the right size cut-to-length pipes or tubing. I actually prefer to hit the bearings into place with a hammer and steel (or aluminum) drift. You can feel the "bounce" when they have found their spot. Not so with a press. There's no feel there and you can actually do damage. I've seen bent wheel hubs from people pressing in new studs. Seen bent housings from people pressing in new bearings, etc.

 

Coat the inside? Totally unnecessary. Clean? Sure, you want to get things clean. These days I use gasoline. It works way better than anything else and I use it to light my burn barrels after I'm done (there's an inside joke here that some Ratsuners will get).

 

There are  a couple tricks I've learned over the years.

1 - when installing/reinstalling studs into the axle housing, use red loctite. Otherwise the oil will leak past the threads. Clean the stud threads by inserting the stud into an electric drill and running them against your bench mounted wire wheel.

2 - for seals, I use gasgacinch. A light coating over the outer surface helps the seals go in easier and then seals them up against the housing.

3 - gasket or no gasket on the diff or the diff cover? Doesn't really matter. If you have "The RIght Stuff RTV", use that in lieu of a gasket. It's tough as nails and seems to be purpose built for gear oils.

4 - Ok, you may need a "bearing splitter" (pic below), but if you're a competent home mechanic, you should have one of these anyway. Buy a good quality one, like from a Snap-On truck, and it will last a lifetime. You'll be able to pass it along to your kids or grand-kids. You can use a bearing splitter to remove bearings from diff carriers by getting them as close as possible and then tapping them into place with a hammer and snugging the bolts at the same time. I have been building diffs for decades and still do not have any of those fancy bearing removal tools.

5 - always apply a bit of grease to the axle shaft before you slide it into a housing. If it rubs on the seal it could tear the seal, so a smear along the entire length of the shaft will help keep the seals healthy.

 

 

I could add much more info here, but I don't know what you're struggling with. If you have any specific questions, just ask.

 

 

Edited April 28 by Stoffregen Motorsports

[frankendat]

1 hour ago, Stoffregen Motorsports said:

First off, you don't need a shop, or any special tools, to rebuild a diff or axle assembly. They only part on an axle that may require a special tool is the bearings pressed onto the axle shaft. Many times, the shaft bearings have a collar that holds them in place, and this is where homeowners get stumped. The simple solution is to drill them and chisel them until they split. Takes about 5 minutes per side.

 

I'm curious why you think a shop has to dot he reassembly? Most times the differential bearings don't need replacing. And even if they do, you can knock them out with a hard metal drift (I use a solid 1/2" steel rod). Installing new bearings is easy with the right size cut-to-length pipes or tubing. I actually prefer to hit the bearings into place with a hammer and steel (or aluminum) drift. You can feel the "bounce" when they have found their spot. Not so with a press. There's no feel there and you can actually do damage. I've seen bent wheel hubs from people pressing in new studs. Seen bent housings from people pressing in new bearings, etc.

 

Coat the inside? Totally unnecessary. Clean? Sure, you want to get things clean. These days I use gasoline. It works way better than anything else and I use it to light my burn barrels after I'm done (there's an inside joke here that some Ratsuners will get).

 

There are  a couple tricks I've learned over the years.

1 - when installing/reinstalling studs into the axle housing, use red loctite. Otherwise the oil will leak past the threads. Clean the stud threads by inserting the stud into an electric drill and running them against your bench mounted wire wheel.

2 - for seals, I use gasgacinch. A light coating over the outer surface helps the seals go in easier and then seals them up against the housing.

3 - gasket or no gasket on the diff or the diff cover? Doesn't really matter. If you have "The RIght Stuff RTV", use that in lieu of a gasket. It's tough as nails and seems to be purpose built for gear oils.

4 - Ok, you may need a "bearing splitter" (pic below), but if you're a competent home mechanic, you should have one of these anyway. Buy a good quality one, like from a Snap-On truck, and it will last a lifetime. You'll be able to pass it along to your kids or grand-kids. You can use a bearing splitter to remove bearings from diff carriers by getting them as close as possible and then tapping them into place with a hammer and snugging the bolts at the same time. I have been building diffs for decades and still do not have any of those fancy bearing removal tools.

5 - always apply a bit of grease to the axle shaft before you slide it into a housing. If it rubs on the seal it could tear the seal, so a smear along the entire length of the shaft will help keep the seals healthy.

 

 

I could add much more info here, but I don't know what you're struggling with. If you have any specific questions, just ask.

 

 

That is fantastic news! I have left my differentials alone since I received the "professionals only" warnings. It could be that I am mixing and matching services incorrectly. I have yet to disassemble a Nissan differential, but I have completely disassembled (even the spiders) FJ40 axles and third member and a Dana 30. The reinstallation of new ring and pinion gears in both instances required a shop with special feeler gauges and special skills. 

 

Now the axles/differentials in question are not changing ratios, it is a restore and refurbish to help ensure operation for years to come. If I am understanding, you are saying that this can be accomplished without removing the parts that require special feeler gauges and special shims? 

[frankendat]

2 hours ago, Stoffregen Motorsports said:

First off, you don't need a shop, or any special tools, to rebuild a diff or axle assembly. They only part on an axle that may require a special tool is the bearings pressed onto the axle shaft. Many times, the shaft bearings have a collar that holds them in place, and this is where homeowners get stumped. The simple solution is to drill them and chisel them until they split. Takes about 5 minutes per side.

 

I'm curious why you think a shop has to dot he reassembly? Most times the differential bearings don't need replacing. And even if they do, you can knock them out with a hard metal drift (I use a solid 1/2" steel rod). Installing new bearings is easy with the right size cut-to-length pipes or tubing. I actually prefer to hit the bearings into place with a hammer and steel (or aluminum) drift. You can feel the "bounce" when they have found their spot. Not so with a press. There's no feel there and you can actually do damage. I've seen bent wheel hubs from people pressing in new studs. Seen bent housings from people pressing in new bearings, etc.

 

Coat the inside? Totally unnecessary. Clean? Sure, you want to get things clean. These days I use gasoline. It works way better than anything else and I use it to light my burn barrels after I'm done (there's an inside joke here that some Ratsuners will get).

 

There are  a couple tricks I've learned over the years.

1 - when installing/reinstalling studs into the axle housing, use red loctite. Otherwise the oil will leak past the threads. Clean the stud threads by inserting the stud into an electric drill and running them against your bench mounted wire wheel.

2 - for seals, I use gasgacinch. A light coating over the outer surface helps the seals go in easier and then seals them up against the housing.

3 - gasket or no gasket on the diff or the diff cover? Doesn't really matter. If you have "The RIght Stuff RTV", use that in lieu of a gasket. It's tough as nails and seems to be purpose built for gear oils.

4 - Ok, you may need a "bearing splitter" (pic below), but if you're a competent home mechanic, you should have one of these anyway. Buy a good quality one, like from a Snap-On truck, and it will last a lifetime. You'll be able to pass it along to your kids or grand-kids. You can use a bearing splitter to remove bearings from diff carriers by getting them as close as possible and then tapping them into place with a hammer and snugging the bolts at the same time. I have been building diffs for decades and still do not have any of those fancy bearing removal tools.

5 - always apply a bit of grease to the axle shaft before you slide it into a housing. If it rubs on the seal it could tear the seal, so a smear along the entire length of the shaft will help keep the seals healthy.

 

 

I could add much more info here, but I don't know what you're struggling with. If you have any specific questions, just ask.

 

 

I did a quick look through the FSM and what I am calling the "differentials" needing the shims and gauges and what not are listed as "Final Drives"

[NC85ST]

Unless there is something wrong with the bearings in your diff’s, why change them? Most likely what’s in there is going to be better quality than what you’re replacing them with. My ‘85 has over 400,000 miles on it and it still has the original bearings and my ‘04 has 316,000 miles on it and it still has the original bearings also. Don’t fix what ain’t broke.

[Stoffregen Motorsports]

15 minutes ago, NC85ST said:

Unless there is something wrong with the bearings in your diff’s, why change them? Most likely what’s in there is going to be better quality than what you’re replacing them with. My ‘85 has over 400,000 miles on it and it still has the original bearings and my ‘04 has 316,000 miles on it and it still has the original bearings also. Don’t fix what ain’t broke.

That has always been my philosophy. Factory diff bearings can last hundreds of thousands of miles. Unless they are chunky or clunky, I'd leave them alone.

 

You can disassemble the diff to inspect the bearings. Be careful to keep everything separate and label them if need be so they go back exactly where they came from. The same goes for shims.

 

If you want to check your R&P pattern before you take the diff apart, wipe some anti seize on three or four teeth of the ring gear (on both sides of the tooth) and spin the diff, by hand, a few rotations. Checking the pattern can give you an idea of the diff health. It can also aid in reassembling the diff. The pattern should never be changed in the lifetime of a gear set.

 

I do not use feeler gauges when installing gears. I use a brake rotor runout gauge to check the backlash and that's about it. A digital caliper to measure the shims and a torque wrench to tighten it all up. Aside from those tools, the aforementioned drifts, tubing and bearing splitter is all you need to build a differential.

 

[Stoffregen Motorsports]

If you do need to replace the diff bearings, you will absolutely need to measure things and check the pattern. Let's cross that bridge when (if) you get there.

[frankendat]

25 minutes ago, Stoffregen Motorsports said:

If you do need to replace the diff bearings, you will absolutely need to measure things and check the pattern. Let's cross that bridge when (if) you get there.

Quick question: In my mind the R200A/R200 (Front and Rear 200mm Rings) are only slightly worse than the removal able third member style H190/H233B. The massive size of the 233, while stronger also makes it a rock magnet. I have the 200's but if I am planning on putting a little money and time in them, is it time to pick and pull the new H series?

 

[datzenmike]

'83 and up 720 4x4 rears were C200 fronts R180

2wd 720s and D21 with 4 cylinder were H-190 rears. 4x4 D21 four cylinder were C200 rear and R180 fronts. Only the VG powered 2wd and 4wd D21 got the H-233

[ElliotV]

1 hour ago, datzenmike said:

'83 and up 720 4x4 rears were C200 fronts R180

2wd 720s and D21 with 4 cylinder were H-190 rears. 4x4 D21 four cylinder were C200 rear and R180 fronts. Only the VG powered 2wd and 4wd D21 got the H-233

Didn't the hardbody also get the r200 front. One of the benefits I can think of to switching to newer diffs is you can get lockers and lower gears

[datzenmike]

Sorry yes they did on VG powered 4x4s.

 

The H-233 only came in 4.375 and 4.625 if you want LSD. 2wd came in 3.90 and 3.70 but you could swap the R&P.