i have a 9 bolt rear end but when i jacked up the rear end and spun one tire forward the other one moved backwards. does this mean i have a bad rear end? also i am going to change the rear end fluid soon because i have no clue when its been changed, what tools are needed adn what kind of fluid should i use? thanks

 

Bad????? Well you don't have posi.. is that bad???

It doesn't mean anything. You could just have an open rear end (aka peg leg). If it's a posi then it could just be in it's fully open mode, or the clutches could be fried.

The best thing you can do is pull the pan and look. All you have to do is undo the bolts from the cover. Start at the bottom and loosen them, but leave them in there. After you get all but the top 3 loose, then pry it open with a flat screwdriver at the bottom while you have a catch pan under it.

You'll need a new gasket. Make sure you remove ALL of the old gasket. You only need 75-90 gear lube, unless you do have posi. If so you'll need to put in the additive for it also. You can get that anywhere, but more people than not recommend the GM stuff.

That's all there is too it. If you have a posi, and it isn't working, you'll have to rebuild or replace it. That can add up fast ($$$) with the 9 bolt.

 

If you were expecting both wheels to turn in the same direction, you'll have to put the tranny in Nuetral first. The tranny being in park is keeping the driveshaft from turning, which forces the rearend to work like a pegleg (turning in opposite directions).

 

yeah, i figured that so i tried in nuetral and park, it turns opposite ways in both park and neutral. i thought a 9 bolt was a posi? am i wrong?

 

There are a few open 9 bolt rears in 3rd gens. 99+% were posi, but a few 3.08 (only ratio I know of) were open diffs. A worn out posi unit will act like an open diff too. More info on 9 bolts is at www.9bolt.com

Miles
Diff Solutions
www.9bolt.com

 

so how long can i run if it is warn out? what kind of warning signs are there?

 

- Almost all 9 bolts are posi disk brake units, but a few open drum units exist.


that is on 9bolt.com but my car has drum brakes in the rear, so is it not a posi? i will find out for sure in a few weeks if we ever get some warmer weather

 

Just for future knowledge, NO clutches in a 9 bolt posi, they are cone type.

Ed