What gearbox oil...GL4 / GL5, synthetic?

Plus 2 Discussions
1

any good answers here?, the +2S130 is up on stands awaiting the doctor’s check up and gearbox top-up.

have just followed Rohan’s advice and pumped the trunnions full of grease already, a fairly free flowing Valvoline type…(red).

:smiley:

2

Thor

All my gear boxes and diffs (4 speed Elan, Pus 2 5 speed, Toyota Landcruiser) run on Redline synthetic gear oils - “MTL” gear oil is the grade for the Elan 4 speed box.

Not cheap but the best.

Rohan

3

I took Rohan’s advice and switched to the synthetic oil for my 5 speed. It made a noticeable improvement to he gearchange quality and also made a noticeable dent in my bank balance!

4

I agree about Red Line although I use GL4 for the box to ensure the synchros work and GL5 for the diff.
Superb stuff and although I strip both box and diff regularly I never find any wear or seal damage
Richard

5

I’m going to change my gearbox oil and just found this thread. Redline have two GL-4 grades, the MTL and the heavier MT-90. Which is preferred?

Does the workshop manual specify what type of oil to use? I can’t seem to find it in the gearbox section or Section O.

I’ve also heard of some folks mixing half motor oil and half heavy gear oil because they found the Redline products to be too thin in their application (Healey 3000). But it sounds like the Redline product works fine for our gearboxes.

thanks
Darren

6

Recommended lubricants are listed in section O8 in the manual.

The original recommendation is for a “80” weight EP gear oil. The current GL 1,2,3,4,5,6 specifications did not exist then

The nearest equivalent these days is a 80W GL4 gear oil. The Redline oil nearest to this specification is their “MTL” which is rated as meeting 75W and 80W specifications and is a GL4 oil which means it has lower sulphur levels making it kinder on brass synchros.

Regardless of all the technical details Redline MTL is the one to use and the best available on the market in terms of both gear life and change smoothness and speed I believe.

cheers
Rohan

7

Went searching for a supplier in NZ and came across this which seems to explain it all pretty well.

racerpartswholesale.com/redtech4.htm

Ralph.