Hi all,

Firstly thanks for all your help on my previous issues, which thanks to you guys i've managed to sort myself. ( without paying someone to do the work )

On to the new leak, i have noticed a very small pool of liquid under the car were it's always kept.
I have been under the car and have found a sticky substance on the floor pan of the car either side of were the drive shaft connects to the rear diff. But i can't see anything dripping when the car is running.
Any advice / assistance on this problem would be really apreciated.

Thanks from Luke

 

It sounds like the pinion seal on the diff is leaking. You will need to remove the drive-shaft and the yoke to get to it. Tricky part is when you are putting it back together after the new seal is in. There is a "crush" sleeve on the pinion shaft that sets the pinion depth. If when you tighten the yoke down you put too much torque on the nut you could actually change the pinion depth in the rear end. That would cause premature gear wear and eventual failure. Also, even though 95% of the diffs had a self-locking nut on the yoke, use a little Loktite to make sure it stays.

 

Is there a repair kit you can buy? or just the seal?, please could you tell me were's the best place to purchase one from, who will ship to the UK

Many thanks

 

i always just mark the nut and the end of the pinion shaft to know how tight to tighten it.

 

You should be able to buy the pinion seal from just about any parts store, as they were used for many, many years, and fit most 10 bolt pinions of the 8.5" units. Summit, JEG's, NAPA, etc. will all have them.
As mentioned, the crush sleeve can't be tightened and crushed further, so care must be taken to not overtighten it when reinstalling and change the lash in the ring & pinion. I usually just take it down snug so it wont change things and as said above I use blue locktite on the threads to hold it good. 20 ft. lbs. would be plenty of torque on a reinstall.

 

you re use the crush sleeve?
I always thought you had to use a new one. I count the threads.

 

I've changed a number of seals on 10 and 12 bolt GM's and never replaced the crush sleeve. Not necessary if you're careful not to overtighten and crush it further.