Help ...Fried Differential... NISTECH...

[s13conv]

I had just put my differential back in after a Phantom Grip intall, and put some gear oil in. I took it down the road at it was nice and quiet. I had put a '92 unit that looked like it had been rebuilt and was nice and tight. Well I get a few miles down the road and it starts making noises. I turn around and go home. I check it out and then convince myself that it's the metal to metal contact from the subframe spacers.

Well, I put about 40miles on it before I decide to check the gear oil and....it was practically EMPTY! I'm hearing a whining when decelerating or at light throttle. Did I fry my side pinion bearings? I put the appropriate amount of gear oil in and drove a few miles and still have the whining.

What damage do you think I did by driving it about 40 miles with almost no gear oil?

Thanks!

[NISTECH]

damaged the gears. at the dealer we just replace them we dont rebuild them. We dont see it to often on the 240 though, mainly the trucks.

[navysnail]

did you put rtv on the cover when you bolted it back on?

[s13conv]

damaged the gears. at the dealer we just replace them we dont rebuild them. We dont see it to often on the 240 though, mainly the trucks.

Thanks.Gears as in ring and pinion or the spider gears? I was hoping to reuse the spider gears because they I had almost 1/8" machined off of them to put the PG in.

I still have the original diff from my '89 w/ 95k on it.

[s13conv]

did you put rtv on the cover when you bolted it back on?

Yep, I put the high temp red RTV on. What happened was, in a moment of temporary idiosy, I treated the drain plug like the fill plug when I put fluid in. I don't know how, but I did.

[red240ne]

It should be fine. 40 miles isn't much, unless you were giving it hell. I had a leak problem in a diff once, after I had removed it. I drove it about 100 miles before I fixed it. Diff still worked great after that.

[IvoryJ30t]

if anything, the spider gears should still be good, but the ring and pinion might be fried.

you should think about a new/junkyard ring and pinion, and make sure the bearings are good, and the backlash and preload are correct. diffs are a pain in the *** like that. it has to be correct or you will chew the gears up.

[s13conv]

The diff in there now is from my parts car. I do still have the '89 diff w. 96k on it in my garage. I'll have to break out the manual and check the backlash and preload that you mentioned.

Then maybe I could just swap the spider gears with the PG?

[Magnes]

...I had a leak problem in a diff once, after I had removed it. I drove it about 100 miles before I fixed it. Diff still worked great after that.

Yeah but your diff had run in oil for a long time, so had some residual oil on the gears and bearings. A rebuilt diff would have been pretty much dry. And still you were lucky.

The pinion bearing takes the most load, if the bearing is OK you're looking good for the rest of the diff. But if the diff is making noise it is fried. You should be able to see damage to the crown and pinion, either pitting or burning of the gear teeth.

[s13conv]

Well, the drain plug had lotsa metal on it. So......