Advice for a Noob: How far should I go on a rear end rebuild? (1 Viewer)

[spike6901]

I am an 80 noob but not a noob to the FJ. Anyway, I bought a '94 (121k miles) and discovered the rear pinion seal was shot. Who knows how long it had been and it had leaked all of the grease it was going to. I spent some time on this site searching and learning and have a decision to make.

I figured it would be smart to replace the front pinion bearing and spacer while I was in there replacing the seal because I can get to it from the propeller side. I spoke with my mechanic and he recomends to do both the front and rear pinion bearings together, which makes sense to me too but doesn't that mean you have to pull the ring, pinion and differential case? Now I am out of my comfort zone so would take it to my mechanic for sure.

So, I then start thinking of the bearings on each side of the differential case and start to wonder if I should replace all of the bearings and seals related to the rear end. I am on a tight budget so this would be tough but not impossible for me to do. If I go this route, should I slap in an Aussie locker while I am at it? I don't plan on running a different gear ratio, at least for a long, long time.

Cost is a big factor for me but I don't want to redo work if I plan on adding the locker later (within a year or so) and I don't know what kind of damage may have occured running for a long time with hardly any grease in the diff.

Maybe I should just go cheap and replace just the pinion seal but I don't want to break on the trail in the middle of no where with my whole family either.

 

[kidglove13]

Is the rear end making any funny noises or acting strange?
If not just replace the pinion seal is my 2 cents

 

[Pin_Head]

Replacing the seal requires you to set up the pinion preload properly, which is a fair amount of work and is difficult if not impossible to do properly with the differential in the truck. The proper way to do it is remove the pinion and install a new crush sleeve and crush it until you get 10-15 inch pounds of preload. The seal may be leaking because the bearing is bad, so you would want to check the bearing while you are in there and replace it if need be.

The EZ thing do do is get a good used differential, and keep the other one for installing an ARB at your leisure.

 

[spike6901]

Is the rear end making any funny noises or acting strange?
If not just replace the pinion seal is my 2 cents

I do have a driveline whine that I have not tracked down yet.

 

[kidglove13]

I am not going to get into how difficult it is to replace the pinion seal and what needs to be done.
You dont need to do all that to replace the seal it is as simple as that, been done a thousand times without doing all that by alot of different folks with no issues.

Since you say you have a whine it could very well be your pinion bearings.

Good Luck with finding your whine
Report back and lets us know what you find or dont find

 

[LINUS]

I did as Pin_head spoke of, mainly to isolate out a "whining" of my own on my 80 (ended up being in the rear 3rd BTW, so that had to be the pinion bearings) - in fact, that's how I ended up going down the slippery slope to ending up with 4.88's & factory e-lockers.

I was initially just going to buy a used, open rear 3rd & was offered a pair of e-locker 3rds (and most of the other needed parts) that I couldn't beat the price on, so I shipped the locker 3rds over to justdifferentials & had them work mine over & add 4.88's (impeccable service, btw - wanted to do the work myself but C-Dan advised to have pro service for e-locker 3rds) while driving on my worn out open 3rds, but for the initial price of an open, any condition 3rd & shipping it out to have it worked over & an air locker installed -- that seemed like the smart money plan before I got carried away - that was going to be my plan before being offered a factory package.

Kidglove's way keeps you on the road for minimal cash, but it doesn't help you long term with the whine issue - so if cash is tight, I'd do that to keep you on the road - it's not like the whine issue is going to grenade on you in the next few weeks - but if you have a few bucks to get a 3rd setup with the optional goodies JT's adds to a Toy 3rd & getting an airlocker installed right (and the peace of mind that buys you), then I'd do that, as it'll also rule out anything in the 3rd as the whine issue.

Also, the 3rd you pull will have some value as a core - JT's bought both my open ones & may even have what you want on a shelf, so you could easily buy a perfect 3rd with an ARB from them & send in your current 3rd as a core, that would make the downtime easily less than a full day (or a weekend if you're as O-C as me) - since you would be just swapping 3rds & doing the work for air to the locker.

Just a few options, since I was in your shoes about a year ago.

 

[spike6901]

Linus, thanks for the advice. I don't have the funds for a new 3rd but I did visit the site you suggested and found one of their master install kits. It contains all the bearings, shims and seals that I need to basially refresh the diff assy, and the pricing is better than what I was finding for OEM.

So, I am going to order the kit and get it installed ether by a buddy or price around a shop.

Again, thanks to all of you for the direction and I am going to consider the problem solved and knowledge gained.