Do I need to use additives or anything? What grade of oil do I need? Also I don't have the rubber bung in the filler- does this matter?

Thanks

 

i use amsoil or M1 sysnhetic, if you have clutch type posi you need gm posi additive, yes you need the rubber plug

 

I have POSI BW.. not sure what the mechanism would be though. Do you think I could find a suitable replacement for the bung, by adapting something else? Would I get away with topping up without any additive? How sensitive are they to getting the absoulute best oil?

Thanks

 

All the info is at www.9bolt.com

Miles

 

I got the replacment rubber plug for my 9-bolt at the Chev dealer. Cost a couple bucks. You must have it.

Re the oil, I heard that if the posi is old and not working well any more, you can bring it back to life by using the synthetic GL5 oil and no additive. I don't know if that's true or not, I haven't tried it.

What is the consensus on that in a 9-bolt?

 

Tremo,

There is no consensus on whether or not to use the additive. Many labels on gear oil will say 'works with limited slip differentials', which does not mean you don't need the additive.

I was hearing a noise coming from the rear of my 87 IROC (BW 3.27) which occurred while bearing left with no load on the drive train.

After reading many posts on this forum and investigating elsewhere on the web, I decided to use Amsoil 75W-90 without the additive. That was about 5,000 miles ago, no problems so far.

 

You do not need the extra additive because the 9bolt has a cone style diff, not a friction plate style like the 10bolt.

Yes, you need the rubber bung or the fluid will shoot out the hole and on to your exhaust causing a James Bond like smoke screen and the ring & pinion slowly welding itself together .

I have used Amsoil and did not like it. I use Redline gear oil and it works fine.

 

007- Licence to smoke

I haven't had the bung in for ages..... Maybe there is no oil in it any more....


Thanks Guys

 

I'd be interested in more details regarding that statement.

I've known of people who used AMSOIL when switching over from petroleum, had one issue or another, switched to something else, didn't have any problem, switched back to AMSOIL and didn't have any problem. That didn't involve gear lube, so if you could expound, it would be appreciated.

 

The rear end made more noise and also chattered a bit with the Amsoil. Switched to the Redline and no problems since.