I finally got the time to take my 9 bolt apart and repair my posi unit. The cones were pretty beat up and bottomed in the carrier. I ground out the bottoms of the cones ( i would prefer machining but my machinist had them for 3 days and didn't touch them, i got them back wed at 11:00 pm) and belt sanded the outer edge for clearance, then i took a flat file to the friction surface to smooth the pits and grooves and to polish it. i put it back together with the shims i bought from Larry and even thought i didn't have enough shims ( my cones were very badly worn) according to stock specs it worked out well. i can now leave 2 very even stripes at will!!! A big thank you to larry for saving me 500 bucks for the new carrier. i hope it lasts until i can afford the 12 Bolt.

 

well thank you Laiky!

what kind of gear oil did you use? any additive?

I used pennzoil GL5 and forgoed the additive. I figure the additive only reduces the friction in the cones, and makes the posi not work. Not scientific by any means, but there is no real proof of the additive being neccessary. the original additive for 9bolts has been discontinued and not replaced. The only GM additive available is the clutch type posi additive.

I havn't been beating on it lately to examine the strips

 

i used royal purple synthetic and an off the shelf posi addative, seems to be working just fine, i think i need wider rear tires. it handles good and lays 2 even stripes when i punch it. i was ecstatic that i didn't have to buy a new carrier, i'm just going to use it till it breaks.

Thank You!

 

TTT

 

After beating on my 9-bolt with et streets, it's making a grinding noise from the right rear when driving. A few times it also made that sound in the waterbox doing a burnout. Sounded horrible, like the thing was coming apart. Doesn't make any noise going around corners, just a slight grinding when going straight.

What symptoms pop up to know the posi needs a rebuild?

 

may have a bad axle bearing?
if it lays 2 dark stripes, your posi works. if not, join the club of 9bolt rebuilders.