Rear end noise (1 Viewer)

[Spook50]

Mentioned this in another thread but figured I should start a new one in case it might help someone else out too. Towards the end of last summer I began to notice a rumble/growl noise in my rear end (separate from the similar but much more aggressive noise I hear at partial throttle or when disengaging the clutch in 4HI). It's slowly become more common, and occurs when braking moderate to hard, accelerating hard and when accelerating around a corner. It was suggested that it could be any one or multiple of the bearings in the either the axle (stock semi float) or the diff. First step, I changed the diff oil when I got home from work today, and this pic is how it looked after just less than a year of use, using Schaeffer's 293 (which when new is a bright greenish yellow color). There was very little buildup on the magnet of the drain plug (small amount of film, but no chunks or anything overly concerning). All the bearings are original, so I suspect that suggestion is likely the case. Now my question is, which would be more likely to go first with age and use? I have been running 31" tires for more than half the truck's like (so not a big difference from stock) but went to wider, 33" tires last May. Is it likely this gave the outer bearings the final push to begin wearing faster and making noise? I'm hoping it's the outer bearings, since I really don't want to tackle a diff rebuild until I can get my hands on an FZJ80 rear and begin setting it up. Also I got the full amount of oil out so there has been none leaking past the (also original) seals, for what that's worth.

What're you guys' thoughts?

 

[rhah]

I had funny rear end noises once, changed the fluid and went about my day.

then I had adventures cause diff pin broke 1200 miles from home

you do what you want but either get the rebuild going or go get your full float axle, don’t be like me it’s not a fun or cheap adventure

 

[cps432]

Mentioned this in another thread but figured I should start a new one in case it might help someone else out too. Towards the end of last summer I began to notice a rumble/growl noise in my rear end (separate from the similar but much more aggressive noise I hear at partial throttle or when disengaging the clutch in 4HI). It's slowly become more common, and occurs when braking moderate to hard, accelerating hard and when accelerating around a corner. It was suggested that it could be any one or multiple of the bearings in the either the axle (stock semi float) or the diff. First step, I changed the diff oil when I got home from work today, and this pic is how it looked after just less than a year of use, using Schaeffer's 293 (which when new is a bright greenish yellow color). There was very little buildup on the magnet of the drain plug (small amount of film, but no chunks or anything overly concerning). All the bearings are original, so I suspect that suggestion is likely the case. Now my question is, which would be more likely to go first with age and use? I have been running 31" tires for more than half the truck's like (so not a big difference from stock) but went to wider, 33" tires last May. Is it likely this gave the outer bearings the final push to begin wearing faster and making noise? I'm hoping it's the outer bearings, since I really don't want to tackle a diff rebuild until I can get my hands on an FZJ80 rear and begin setting it up. Also I got the full amount of oil out so there has been none leaking past the (also original) seals, for what that's worth.

What're you guys' thoughts?

View attachment 2602719

My vote is for the carrier bearings in the case. I will give contrary experience to rhah and say that I ran my rear end with a gnarly howl and clunk for almost 5 years before I swapped it out and I ran cheap box store oil in it the whole time. Not gonna lie, I was sh!tting bricks the entire time expecting to throw a pin like rhah. You could be fine for a decade or it could be the end tomorrow.... sorry to say, but you’ll probably want to open that chunk up and take a peek just to make sure everything is still staked and torqued. In the meantime keep the oil fresh and try not to push it too hard. (Says the guy who used the busted truck to move three times in that 5 year period)

In woodworking we learned that there’s no mistakes or broken projects, just design opportunities! So... this is the candle under yer ass to get that 80 axle swap movin’!

I had funny rear end noises once, changed the fluid and went about my day.

then I had adventures cause diff pin broke 1200 miles from home

you do what you want but either get the rebuild going or go get your full float axle, don’t be like me it’s not a fun or cheap adventure

View attachment 2602764

View attachment 2602765

View attachment 2602766

View attachment 2602767

I remember when this happened!

 

[Skniper]

Outer wheel/axle bearings tend to be more constant groaning. Jack up the rear and check for any play in the tires from 6:00 to 12:00 o’clock. Remember, if it’s outer wheel bearings you are beginning to ruin the SF axle(s).

 

[Spook50]

So it looks like I'll be gathering parts to rebuild my diff, since I'm paranoid and don't have the money or downtime for an FZJ80 yet. I still have to order another U joint from Cruiser Outfitters since I busted one when doing my front driveshaft, so I'll be giving them a call soon it looks like.

Not a fan of being stranded....

 

[Godwin]

If you're pulling the diff and have a lot of miles on rear plan on replacing the rear wheel bearings and seals, and maybe brakes if they need it. Cheaper than a rebuild is to find a good used diff (62 or rear 80 series will work), or swap the front and rear instead of rebuilding the rear at this time.

 

[RredFJ40]

If you're pulling the diff and have a lot of miles on rear plan on replacing the rear wheel bearings and seals, and maybe brakes if they need it. Cheaper than a rebuild is to find a good used diff (62 or rear 80 series will work), or swap the front and rear instead of rebuilding the rear at this time.

I’ll echo Godwin, try swapping the front and rear diffs and see if the noise follows or stays. If it follows, then ride it out for a good long time as your front diff will see a lot less work.

 

[Spook50]

If you're pulling the diff and have a lot of miles on rear plan on replacing the rear wheel bearings and seals, and maybe brakes if they need it. Cheaper than a rebuild is to find a good used diff (62 or rear 80 series will work), or swap the front and rear instead of rebuilding the rear at this time.

I was of the understanding that a SF rear diff couldn't be swapped into a 60/62 front. Was I mistaken?

I'll plan on starting with the outer bearings and seals. Brakes are way good on the back still (did em a year ago too). While I have it apart I'll pull the diff and inspect it as best I can. Any pointers on what to do and look for while it's on the bench to determine its condition would be great. This will be the first time I've done anything in a diff. Paging @orangefj45 @torfab @cruiseroutfit

 

[RredFJ40]

You are mistaken. You just need the pinion shaft block from the rear. Take them both out and set them side by side.

 

[torfab]

They can be swapped, but before you pull the diff you can do some other checks. Put the transmission in neutral and set the e-brake then see if the rear pinion has any play up and down or side to side, in and out. If it does then go straight to rebuilding the diff, and if not then look at the axle shaft bearings first before pulling the diff.

You'll get a good look at the wear pattern once you pull the diff cover, if you have any marks or burrs then you know you need to rebuild and also install a new gear set.

 

[Spook50]

They can be swapped, but before you pull the diff you can do some other checks. Put the transmission in neutral and set the e-brake then see if the rear pinion has any play up and down or side to side, in and out. If it does then go straight to rebuilding the diff, and if not then look at the axle shaft bearings first before pulling the diff.

You'll get a good look at the wear pattern once you pull the diff cover, if you have any marks or burrs then you know you need to rebuild and also install a new gear set.

Cool. That's on the list for this weekend then

 

[dbleon]

I just swapped my f/r diffs. Not too bad a job... hardest part was getting the old gasket material off

 

[Spook50]

So if there's a break in the rain today I'll go outside and check out my rear diff using @torfab's instructions. I'm confident that I'll at least be ordering an outer bearing kit for my axle, and should the diff bearings be bad I'll have to order a rebuild kit. I plan on going through Cruiser Outfitters for both. I noticed though that for their diff kit they say they provide Timken bearings. I've always religiously used Koyo bearings in my 62 when I've done any bearing replacements, and since they say they will provide Koyo bearings on request, I intend to go that route. Curious though, am I the only one who insists on sticking with Koyo bearings, and is there REALLY any quality difference between the two nowadays?

I'm also getting together a tool list for the job. I plan to get a differential adapter for my engine stand, a bearing splitter, a carrier bearing adjuster socket, a 20 ton shop press (using this as an excuse to finally get one lol), and a dial indicator style torque wrench for checking pinion bearing preload. I already have an impact and appropriate sockets. Any other recommendations that would make the job go smoother? I watched @OTRAMM's diff rebuild video on Youtube, and I'm confident I can tackle it as long as I can take the time to make sure gear alignment ends up spot on by the time I'm finished.

 

[cps432]

So if there's a break in the rain today I'll go outside and check out my rear diff using @torfab's instructions. I'm confident that I'll at least be ordering an outer bearing kit for my axle, and should the diff bearings be bad I'll have to order a rebuild kit. I plan on going through Cruiser Outfitters for both. I noticed though that for their diff kit they say they provide Timken bearings. I've always religiously used Koyo bearings in my 62 when I've done any bearing replacements, and since they say they will provide Koyo bearings on request, I intend to go that route. Curious though, am I the only one who insists on sticking with Koyo bearings, and is there REALLY any quality difference between the two nowadays?

I'm also getting together a tool list for the job. I plan to get a differential adapter for my engine stand, a bearing splitter, a carrier bearing adjuster socket, a 20 ton shop press (using this as an excuse to finally get one lol), and a dial indicator style torque wrench for checking pinion bearing preload. I already have an impact and appropriate sockets. Any other recommendations that would make the job go smoother? I watched @OTRAMM's diff rebuild video on Youtube, and I'm confident I can tackle it as long as I can take the time to make sure gear alignment ends up spot on by the time I'm finished.

Getcha a slide hammer and wheel bearing puller kit. I rented the one from oreilly. You’ll trash those bearings pulling them out.

You will be so glad you have the 20T press now. I’ve used it more than I expected and I feel confident in future work since I have it now. I couldn’t have done the transfer case without it and I had originally bought it for doing diffs. I ended up having cruiseroutfitters do the set up and I just dropped in the chunk.

As far as bearing brands go, I have heard that Timken are now made in a different country but I’m not sure. If cruisers is selling them I would trust that they are solid and reliable and I assume they used Timken in diffs I got from them. I’m not too worried about it, but if you can get koyo why not? But if I’m not mistaken Nachi were the OEM carrier bearings.

 

[gbogh]

If it doesn't come with the rebuild kit, I'd get some gear marking compound It looks like the kit comes with hear marking compound. You can go by feel & be okay, but a dial indicator with magnetic base is pretty key for making sure your backlash is in spec.
Also, any vehicle I intend to keep long term gets a solid pinion spacer if the diff is disassembled.

 

[Spike Strip]

My wife complains about my rear end noise all night...

 

[Spook50]

If it doesn't come with the rebuild kit, I'd get some gear marking compound It looks like the kit comes with hear marking compound. You can go by feel & be okay, but a dial indicator with magnetic base is pretty key for making sure your backlash is in spec.
Also, any vehicle I intend to keep long term gets a solid pinion spacer if the diff is disassembled.

Already got a good Mitutoyo with a magnetic arm, so I'm good there. I hadn't heard of using a solid spacer in lieu of the crush sleeve before. Looking it up, sounds like not a bad idea. Not planning on keeping this axle for the long term at this point (wanting to do an FZJ80 rear end swap ASAP), but it sure wouldn't hurt, given how inexpensive the solid spacers are.

 

[poptart]

For the outer bearings, I had zero luck with a slide hammer. End up using this guy.

 

[Spook50]

For the outer bearings, I had zero luck with a slide hammer. End up using this guy.
View attachment 2606470

I was eyeballing one of those actually. Be handy for other bearings I think too, so I'm thinking I'll get one of these rather than a slide hammer. Did you get yours off Amazon?

 

[poptart]

I was eyeballing one of those actually. Be handy for other bearings I think too, so I'm thinking I'll get one of these rather than a slide hammer. Did you get yours off Amazon?

Yeah it’s the OTM kit on Amazon, seems decent enough if your not a professional and are only going to use it a handful of times.

Amazon product ASIN B07BNMB42N