I've noticed my rearend isn't the rearend that came with the car. What can I look for on this rearend to find out what kind it is. It has markings on it from a SALVAGE YARD. But, I think it may be a posi.

 

Count the cover bolts. If it's 10, it's the more common 10 bolt diff used on third gens. If 9 bolts, you lucked out and got an Australian diff that is much stronger than the 10 bolt.

 

MY REAREND HAS A 10 BOLT. SO WHAT ALL DOES THAT TELL ME ABOUT THIS REAREND. HOW CAN I FIND OUT IF ITS ACTUALLY A POSI. TAKE IT APART??? PLEASE HELP...

 

If you throw the rear up on jackstands, put it in drive or 1st and spin your tires by hand. If they both spin the same way, its a posi, if they spin opposite, you have an open diff.

If were interested in trying to figure out what ratio you have, mark your driveshaft with chalk or crayon. Then mark one of your tires with chalk or crayon and spin your tire by hand. Watch how many times your driveshaft will spin when you spin your tire once.

For example; If you have 3.23 gears, your driveshaft will spin 3.23 times in one revolution of the tire.

 

OOOPPS!!! I forgot to mention the burnout test.

Look to see if you leave 2 marks or 1 mark.

 

There should be a tag on one of the bolts on the diff cover that will tell you every thing about that rearend.

 

On the front of one of the axels there is apparently a marking... I have yet to find mine... But with that you can look it up and find gearing and wether you have posi or not (unless someone changed that too)

 

OH yeah... otherwise pull the cover... there is a stamping or you can count the gears and do the math.. (divide how many ring gears by how many pinion) also springs indicate posi

 

i like the burnout test the most

for best results, do it on your neighbour's front lawn

 

I believe you mean count the teeth on the ring and pinion gears.
Cause there is only one of each.

 

Yeah yeah yeah he knows what I mean I know what I mean and you know what I mean... my hands are sore and I didn't feel like typing the few extra words... although now I have to type this stupid post arrrrggggg...........

 

Its all good bud. Just razzin' ya.

 

I just had a clutch job done and didn't think about spinning the tires while it was on the rack. Actually when it was on the rack is when I noticed the salvage yard markings on the diff cover. I've done the burnout test which lead me to believe that it may be a posi. But I didn't try it on the neighbors lawn though. I'll look for other markings. I also have drum brakes on the back. I thought a posi would have disc. Then again I don't know what year vehicle this rearend came from, but I'll do some more looking. It'll be back on the rack this week. I'm upgrading the front brakes to BAER, adding SS brake lines, MOOG front end, 1in drop springs and KONI yellows.

 

Go with Wilwood 6-piston calipers, there only $2500.00....