Did a search, but one real answer I could find is this cut and paste observation from Icemark:

Redline Shockproof gear oil for the rear end (an add some Red Line Limited-Slip Differential Friction-Modifier/Break-in Additive if you have a LSD- which if it is a 88 GXL from your sig; it should).

Two questions:

1. Do you put the same LSD Additive no matter what type of LSD (disc, Torsen, etc)?

2. What are alternatives to Red Line Gear oil and additive.

- For instance, Royal Purple intrigues me. Anyone with insight or experience. I have to assume Royal Purple also provide an LSD Additive. True? Couldn't tell from their web site: http://www.royalpurple.com/retail/pr...products.shtml

- Other suggestions??

Individually, we're smart. Together we're genius. Thats why this Forum stuff is so great. Thanks for your responses.

Drive well, drive safe.

 

Amsoil comparison (albeit dated 1995) to several other synthetics (including Redline) and non-synthetics.

http://go-synthetic.com/redline_vs_a...vs_amsoil.html

 

No, LSD additive is needed on clutch/cone type LSDs.

Viscous fluid LSDs are sealed and quaife/zexel gear types use gears and neither need LSD additive.

Amsoil, Neo, Synlube, Redline, Mobil1, Royal Purple

 

Anyone with experience on these alternatives??

 

Mazdatrix pushes NEO.
RacingBeat pushes RoyalPurple.

I've used Amsoil, Redline, Royal Purple and Mobil1.
Synlube's cost is unreasonable at almost $35 a quart.

In the rearend, you can't tell the difference between any of them. In the 5 speed xmission, you can.

 

What do you recommend? And, any idea which brand is the most cost effective?

 

I use the Redline MT-90 in the transmission and this is the only fluid that I would recommend in any/all manual transmissions that needs 75/90 or 80/90 oil.

I use Mobil1 in the reargears because it is readily available at most car parts stores around here.
Both are reasonable at ~$8 a quart.

Amsoil/Redline/RoyalPurple are usually in the specialty speed/4x4 shops around here. They are usually $10-14 a quart. I haven't seen Neo or Synlube on any store shelves. If I do, I might grab some and give it a shot.

The words cost effective really don't mean much with transmissions/rearends. You change the fluid once and forget about it until a major service occurs(clutches/axles.......).

 

I like NEO from www.bakerprecision.com .

 

I get my royal purple from NAPA auto parts at ~ $8 a quart for gear oil and ~$5.50 quart for motor oil. Check out your local NAPA auto part store, not very hard to find in SoCal.

 

$7 per quart for 75W90 from my friends at Racing Beat, and it already has the LSD Molifyer in it.

Thanks for all the suggestions.