SLEEPER 86

I recently picked up a used 9 bolt rear, but due to circumstances i was unable to inspect the ring and pinion gears. When I finally pulled the cover, I found some rust on 4 or 5 of the ring gear teeth. It looks like only 2 of the teeth are rusted on the contact pattern.
Am I screwed? Is there a way to polish these teeth down? Should I just drive it til it breaks?
Any input is welcome here!
Thank's Guys!

jakemussman

iTrader: (3)

Are we talking about a light bit of surface rust? or cancerous?

SLEEPER 86

looks like some of it might be cancerous, it's worse on the back of the teeth than the leading edges. I'll post a pic as soon as i get batteries for the camera.

jakemussman

iTrader: (3)

Pics will help. The concave side ( <- is the coast side of the tooth.
The convex side -> ( is the drive side of the tooth. If the rust is cancerous and has severely pitted either side of any of the teeth I wouldn't bother using them. They may be weakened and will more then likely make a lot of noise when in use.

SLEEPER 86

should i try wire brushing it? maybe a green scratch pad to look for pitting? on my way to get camera batteries

jakemussman

iTrader: (3)

The green scratch pad shouldn't hurt anything. the internals of the differential rust extremely fast when exposed to moisture. When I was rebuilding mine I had the housing out side when I was cleaning it. It started raining so I brought it in. A little moisture got in and formed rust in just a few hours. Brake clean and a scrub brush took care of that though.

SLEEPER 86

well, the camera isn't working now!
when i get the gears in good light i see significant pitting on both sides of 5 teeth. it's mostly to the outside of the gear, like the diff was sitting yoke up and there was water in the cover. further inspection revealed that the posi cones are bottomed out (or extremely close) on the carrier, the passenger side carrier bearing has some rust on the housing, and there is mild pitting on the wheel bearing race.

red rock

iTrader: (2)

As you just stated, there is usually more rust to be found when you break it down. If you plan on keeping it, I would look at a complete rebuild. If the cones are not bottomed out, you can rebuild the carrier. What gear ratio is the rear?

SLEEPER 86

it's a 3.27, if i have to rebuild it i'd probably do a 3.70. might be beyyer to just look for another one, but i have the housing cleaned and prepped for POR-15.
the cones appear to be bottomed, but i'll have to get a feeler in there to be sure.

red rock

iTrader: (2)

If it's not bottomed out too bad, you can buy new cones, which are a little oversized to take up the slack from wear. Here are some links;http://9bolt.com/ , http://mpikas.blogspot.com/search?q=9+bolt+borg+warner

jakemussman

iTrader: (3)

Like Red Rock said your probably looking at a full rebuild. It would be a waste of time to install it and have it go out on you a couple hundred miles later.

articwhiteZ

iTrader: (56)

bolt it in and run them..the run in will polish out any rust.

it's not going to make a sound.

red rock

iTrader: (2)

I'm just wondering, without seeing the rear end, Would you run a motor with rust in the bearings and gears that are pitted. Why would you give out advice like this. What if the bearings seize up and or break. Most people don't look at a rear differential as a precision piece of equipment, unless you have rebuilt one. But they take all the abuse a motor and transmission, brakes and weight can throw at them.