Tomorrow I'm putting a diff in my '84 GSL-SE. Here's a few questions left unanswered by a search.

1. I know this is a LSD. Is this a viscous or clutch type limited slip, or something else altogether?

2. It seems that the general consensus is that I ought to use Redline 75/90 synthetic gear oil. That being said, when I read posts recommending this, it didn't specify whether this is OK for both open diffs and LSDs. Is it?

3. I will probably have to drive to Akron to get Redline. I really don't want to do that. Is Royal Purple acceptable? Is there a better alternative to Redline?

4. What is the fluid capacity of the diff? Somebody said "about 1.5 quarts," but they once again didn't specify which diff it was for.

5. Is there anything that makes this procedure different from any old, small, RWD, solid-axle car?

6. Do I need any unusual tools?

Thanks.

 

1) It's a clutch type.
2) It's good for both.
3) Royal Purple synthetic is endorsed by Racing Beat, so it must be good. Even though I can readily get most brands, my preference is to use inexpensive Castrol mineral gear lube with GM's LSD additive.
4) 1.5 quarts sounds about right. I try to pump in the entire two quarts.
5) No.
6) No.

 

If I use Royal Purple synthetic, do I need LSD additive? If so, what brand should I use, and when I look for it on the shelf, will the label say "LSD additive?" What should be the ratio of LSD additive to a quart of gear oil?

 

The LSD additive is a GM part #, and you can ask for it at any import parts house as an "LSD additive". They'll know what you mean.

You put the whole contents of the LSD additive bottle in first, then add the gear lube of your choice. I went with Royal Purple and it runs very quietly - I don't hear the clutches clicking, either.

HTH,