What would be the majority choice for quality and value for money regarding the transmission fluid and differential fluid for the LSD rear in a 84/85 GSL.

Steve

 

Tranny fluid is just a standard 80W90 gear lube. I would suggest Redline or royal purple. As for the rear end, you need to add a friction addictive to a regular 80W90 gear lube. Use same gear lube as for the tranny, just make sure you add the friction addictive otherwise you WILL wreck your LSD rear end.

 

Transmission:
Amsoil or Redline MT fluid. The amsoil is 75-90 I think, and the redline comes in MT and MT-90. Both are highly recommended. For a less expensive fluid go to Valvoline gear oil or Mobil 1 gear oil(I don't think either make a MT(GL-4 lubricant)). I use the Amsoil or Redline in racing applications and have never lost a transmission yet. Remember that a GL-4 lubricant is better in the trans than a GL-5 unless recomended by the MFG.)

Differential:
Amsoil severe duty gear oil, Redline gear oil. Both are GL-5 lubricants that work gread in LSD's without an additive. Less expensive alternatives here are plenty. As above Mobil, Valvoline and lots of other make good synthetic GL-5 gear oil. Again I use the amsoil and have never had a failure, street or race.

 

Check out LUCAS OILS amazing stuff

 

neo, amsoil, royal purple, redline all work great in our transmission(and diff)

im about to try some lucas...we'll see how it goes.

 

Use Lucas where ever you can...

 

How long have u guys been using Lucas gear oils? I was lead to believe that until recently they were just an additive company. I don't know any road racers that have to pay for their own stuff that use Lucas oils. The oils that I see at the track(road racing) are: (in no particular order)
Valvoline
Amsoil
Royal Purple
Neo
Redline
Mobil 1

 

I use Royal Purple and a few shots of Lucas

 

im using lucas because i HAVE to. im actually a royal purple guy...

no parts stores on my island cary any of the brands i'd like to use...so...ill just have to test them out.

and mobil 1 gave me a 3rd gear grind(replaced with RP and it went away)

 

Dont use Redline MTL in the trans.Be sure to run Redline 75-90W.The MTL is a direct replacement for trannies that require ATF or 10-30W in the trans.The MTL is too light and not recommended for boxes that require actual gear oil.It will work,but you could experience gear clash.I run 75-90W Redline in my TII box with much success.
In the rearend I also run 75-90W Redline.It has the friction modifier in it already.If your going to be hard launching or thrashing the car,you can run lightweight Redline Shockproof gear oil for more protection.The stuff is like molassass,but it works great,I run it in my rockcrawler.
Before switching to any synthetic oil,its good to change the seals in the trans and rearend to prevent leaks.
Budget is one thing,but synthetics work so well and the drivetrain components require oil changes in such long intervals,its worth the cost for more protection.....

 

MTL is 70w-80. If you're worried about the thickness run MT-90 which is 75w-90. Regardless, I'd run the product that is actually designed specifically for use in a manual transmission as opposed to the gear oil they sell.

MT-90 completely cured the 3rd gear crunch on my TII box.

 

http://www.bobistheoilguy.com/images/lucas/lucas.htm

Funny thing is that all the counter people that work at auto parts places claim that they use lucas additiives exclusively. Maybe they get a sales commission on lucas additives?

"Bob, the oil guy" prefers Schaeffers 267. I've never heard if Schaeffers.