Transmission / Overdrive: proper T-10 4 speed lubricant?

[wagonairedriver]

Decided to change the gear oil in the Avanti and wondered if I should be using the same GL-1 mineral oil as in the T-86 O/D in the Wagonaire... I couldn't find the spec anywhere.
Thanks, Kelly

[StudeRich]

Yes that is good Oil for most all older Borg Warner Transmissions. A 4 Speed will shift smoother if you drain it and change to Red Line Synthetic gear oil though.

[okc63avanti]

If using Non-synthetic use 75W-90 or 80W-90 GL4 Gear Oil. Do not use GL5 it will corrode brass syncros.

If using synthetic use Amsoil MTG 75W-90 GL4 or similar synthetic GL4 gear oils ... http://www.amsoil.com/lit/databulletins/g2077.pdf

[Bud]

I used the Redline MTL gear oil in the 4 speed trans in my 62 Hawk. I spoke with the Redline tech rep and that is what he recommends as a replacement for the old GL-1 gear oil in Borg Warner transmissions. Bud

[StudeRich]

OK so now we have a problem; one verified usage is MTL, the other non-verified by Red Line usage is MTG probably recommended by our Knowledgeable Avanti experts Jon and Mike Myer, (MY assumption).

So someone has to be not as correct, probably there is NO wrong Synthetic.
If these are control specs, the Brand should not matter.
Which is it?

I would refer to the Grade of Red Line that Ted Harbit has successfully used on all of his high speed Drag Strip runs, but I do not recall which it is.

Non Synthetic Gear Oils have never been a problem, we all know you must use
GL-1, 90 or 85W-90Wt.,
NOT GL-4, NOT GL-5 or any "Combination of grades" one size fits all, type in our Borg Warner Manual Transmissions.

[E. Davis]

Decided to change the gear oil in the Avanti and wondered if I should be using the same GL-1 mineral oil as in the T-86 O/D in the Wagonaire... I couldn't find the spec anywhere.
Thanks, Kelly

I use Redline synthetic 75/90 GL4 with no problems. The owners manual that came in my 61 hawk says in t-10's to use 80/90 multi-purpose gear oil...whatever the hell that is could be anybodys guess.

[StudeRich]

I use Redline synthetic 75/90 GL4 with no problems. The owners manual that came in my 61 hawk says in t-10's to use 80/90 multi-purpose gear oil...whatever the hell that is could be anybodys guess.

That is very easy to explain, in 1961 there was no GL-4 and certainly no GL-5, they meant GL-1 Mineral Oil which is all they had.

[JoeHall]

OK so now we have a problem; one verified usage is MTL, the other non-verified by Red Line usage is MTG probably recommended by our Knowledgeable Avanti experts Jon and Mike Myer, (MY assumption).

So someone has to be not as correct, probably there is NO wrong Synthetic.
If these are control specs, the Brand should not matter.
Which is it?

I would refer to the Grade of Red Line that Ted Harbit has successfully used on all of his high speed Drag Strip runs, but I do not recall which it is.

Non Synthetic Gear Oils have never been a problem, we all know you must use
GL-1, 90 or 85W-90Wt.,
NOT GL-4, NOT GL-5 or any "Combination of grades" one size fits all, type in our Borg Warner Manual Transmissions.

Rich,
On the Red Line bottle, largest letters are, MT-90. Lower down of the label, in smaller letters it says, 75W90 GL-4. That's the same stuff Ted uses. I have been using it a few years now, since I read where Ted mentioned it.