I'm replacing the entire rear diff on my 2000 4Runner with a diff I bought from a yard, and I'm using my existing housing.

The inner gears that the axle shafts make contact with have a retainer-type bolt holding the gear in that position. To the best of my knowledge this is a 'dial-an-adjustment' design to allow fine tuning the position of the gear during assembly.

My question is, is it safe to assume that the current setting on the replacement diff has those gears centered so that I don't have to make any adjustments myself, and that I'll be able to simply reinstall the axles and they'll be seated properly? If not, any idea on how to go about making the proper adjustment for each axle? And if it turns out they're not properly adjusted when I start driving, will I hear a noise?

Thanks to everyone that can help with this technical question.

 

differential set up is an art. if you have questions as to the set up of a junkyard diff take it to a shop and have it checked

 

There are a couple well written threads with pictures on how to set up your diff. If you're in doubt, take both thirds to a mech shop and have them do it.

 

Thanks, it appears I'll have to do a deeper search as I didn't see any of diff setup posts. Unfortunately I don't have the funds right now to have a shop do it so I'm stuck in that respect.

 

one could assume that if the diff came out of a rig that had been driven regularly (decent mileage on it), then the diff would have grenaded at some point before you getting it. unless there's obvious signs of funky wear patterns on the gears or even metal shavings found in the residual oil (since junk yards don't usually clean their parts) - i would personally say you're good to go. i did it on my truck when i got 4.88 gears. if you can afford it, it's always a good idea to have a gear expert take a look at the diff and do any adjustments needed, perhaps refresh it with a solid pinion spacer vs crush sleeve.

 

From what I can tell, it's from the same rear end that that yard had for sale last fall that I couldn't afford. They apparently sold the housing and elocker separately and only had the diff left to sell.

It still had an oil coating on all the interior parts but there were also some grains of sand and a little bit of an on/off gritty sound when you turn the driveshaft flange. I didn't see any broken teeth or anything so figure I have 30 days to get it on the truck and make sure it's good. I have no idea what a pinion spacer vs crush sleeve means. I'm hoping merely to clean this up, bolt it to my housing, reattach my rear end to the truck and be able to drive it again.

I'd really like to clean it up with some brake fluid but nobody has responded to that particular question yet.

By any chance do you know if I can spray brake cleaner liberally all over the interior to rinse any debris/grime/sand out of it? Or will that have the side effect of dissolving some area of grease or something around the pinion bearings or seal that could cause damage?

 

EDIT: Instead of brake cleaner, do you think MAF sensor cleaner would be a safe alternative to rinse out any grit from the diff?

 

just use brake/parts cleaner and let it dry afterward, that stuff dries crazy fast. shouldn't really leave any residue afterward. i would try not to get it on the pinion seal though if you can avoid it.

 

Actually, after reading the label on the brake cleaner, I've decided to not use brake cleaner. I may consider using a can of Mass Air Flow sensor cleaner instead, if someone can confirm that it won't do any damage to any of the differential internals.

With regards to avoiding the pinion seal, that's the area I'm trying to clean (from inside the diff as well as from the lip around the flange at the driveshaft) because I believe some dirt or grit got into it, as I can hear a slight raspy sound come and go as I turn the shaft.

 

You won't hurt anything metal in that diff with any type of cleaner/degreaser. The seal MAY be damaged by certain chemicals.

If that diff sounds gritty or crunchy in any way after cleaning it and re soaking it in some gear lube , I wouldn't run it without it being inspected.