I'm thinking of getting a 3.92 posi rearend (axles and all, but not brakes) from a nearby junkyard. What should I look for when I pull the cover? Obviously metal shavings and broken parts, but what else? Is there any way I can check the bearings?
I know exactly nothing about rearends, so please put everything in the simplest terms you can.
Also, I'm sure Dakota and Durango rears swap, but what about the ones from Rams and other full size vehicles?
Thanks, Gas.
BTW, I've got 2001 Durango with 3.55 open rear. I just posted here because there are more people here and I know it's the same for these two vehicles.

 

Not many have the 9.25- They exist, good job if you find one. But you won't find a Posi, only a LSD, that's if you're lucky. The 1500's have the 9.25 with LSD, but entirely too wide for our trucks. A posi is a solid spool, and that's not streetable.

 

Thanks. I guess LSD was what I really meant. There are 2 yards right next to each other, and the vehicles are in some semblance of order, so it won't be hard to check. At least I know not to get one from a full size vehicle.
Assuming I do find one, what should I check for?

 

You'll need to take it completely apart, so be prepared to have tools to set the backlash and such-

Good things to check and replace- axle bearings, axle seals, carrier bearings, pinion bearing, pinion seal, and since you're wanting the LSD, make sure it's in good condition. I don't know much about axles though, but that's a starter list. When you button it back up, you'll want to do the full backlash check, pre-load spec, ect. There's alot to check, simply because you don't know what you're getting from a JY. I don't know exactly what trim packages have the 9.25 in the dako/durango. I think it would be safe to say, the big motor/trailer package is probably a safe bet. I know the 3.92 was std with tow package, LSD was optional though.

 

When you pop the cover off, look for discoloration (blackening) of the metal components, it can indicate burnt oil which would be a sign of neglect. Rotate it by hand and listen and feel for noises and shudders.

The v6 and V8 has different size driveshafts. V6s are 8.25" and V8s are 9.25" drive shafts. So make sure you are getting something that'll work on your v8.

A bearing rebuild kit should be able to be obtained for a little under $200 and that'll replace all bearings and seals. Therefore, what is important is the condition of the spider gears (the little guys in the chunk in the middle), ring (big a$$ circular gear on the left) & Pinion (cone shaped gear that turns the ring gear coming from the driveshaft) gear. Unfortunately, you won't be able to see the condition of the pinion bearings w/o taking the assembly apart (other than turning the yoke and feeling for resistance). The conditions of its storage should be considered. Surface rust on the brake components is no big deal, but if the cover has been left off for a prolonged period of time, it may have ruined the internal components. A place that offers warranties would also be nice.

Good luck.

 

I lucked out a couple of weeks ago when I got one.
Mine was an 8 1/4 open with 3.55.
I picked one up sight unseen for $200.
It turned out to be a 9 1/4 LSD with 3.55. bolted right in with my old backing plates and brakes. Only problem was finding U bolts to fit the larger tubes.

 

I just checked car-parts.com for my area, I live between a total of 6 yards within 10 miles, theres a bunch of 3.92's around here, all coming from dakotas with the 4cyl

 

Good find. The 9.25" is a solid rear end. I wasn't quite sure if the axle housing was literally interchangeable with our backing plates. Cool. I do know that the drum and rotor axle tubes are interchangeable. That rear end will out last your truck now

 

Someday soon, I'll have the time to get over there and see what they have. I'll even take a pegleg if that's all they have. $60, can't beat it.

 

Went to the pick and pull today and found a dak with 3.92 lsd I really wanted to ****** it up but I dont have money to do that right now but I did scarf a chrome jeep grille and 4 infinty speakers for 40.00 I never thought the wiring would still be intact but I hooked my jumper box to the batt cables and got the radio to work and they sounded really good.