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gear box oil

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ekamm

ekamm

Jedi Warrior
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I'm not trying to spark a debate but, After spending a couple of hours searching this sites archives and google I've learned little. I am only concerned with a NON-OD transmission. I know what the old factory recommendations are and the differences in newer and older oils are. What oil do I use in my TR3a non-overdrive gearbox?
 
As I'm sure you've noticed, there is no clear consensus on this topic. As I see it, almost any of the suggestions will work reasonably well, particularly if you don't drive the car hard.

My personal preference is for Redline MT-90. This is a full synthetic, GL-4 oil that has been specifically optimized for synchronized manual gearboxes, and does not contain the "active sulfur" additive that can attack yellow metal components over time.
 
I, too, use the redline MT90 -- in my case for about 15 years or so. Can't recall if I read that here or figured it out all by myself. Sorta expensive but considering how little it takes and how seldom I change it, cost per bottle is not a big deal.
 
Any of you using MT90 in an OD?
Any of you tried MTL?
 
I first read it here and switched to Redline MT-90. Thought gears shifted smoother, particularly thought it helped syncronizers do their job better. Have since switched the Ford and Chevy over too.
 
I tried the MTL but seemed to lose it out the seals very quickly. Not so much with the MT-90.
 
I use the 75w-90 gear oil in the diff with no leaks.
 
For the diff, I prefer Valvoline full synthetic gear oil
https://www.valvoline.com/products/consumer-products/grease-gear-oil/gear-oil/59

It's "slicker" than the MTL, with better protection for the hypoid gears in the diff. And even though it is rated GL5, it still doesn't use the "active sulfur" additive that can attack yellow metal (found in Triumph diffs).

The diff in TS39781LO was already well worn and sloppy when it came to me in 1984 or so. After well over 100,000 miles more with the Valvoline gear oil, it's no worse than it was. And I did drive it pretty hard (1st in class at 2000 VTR autocross, then drove 1000 miles home).
 
I have used Redline MTL in my TR3A trans, which is actually from a TR4. Shifted easier when cold and I did not notice an increase in spots on the cookie sheet under the car.
 
Moseso said:
Any of you using MT90 in an OD?
Click to expand...
Yes, both A-type & J-type. Works great. Wasn't a true "before and after" because I also shimmed up the pressure, but the A-type in particular seems to shift more smoothly and positively with the MT-90 than the previous VR 20W50.

I also asked Redline, and the MT-90 is what they recommended for a Laycock OD.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Any of you tried MTL? [/QUOTE]I haven't, but the only real difference is the viscosity. The thinner oil might make it more difficult for the OD to build and hold pressure (there are no seals/rings on the pump piston), but maybe not enough to notice. I did my bench OD tests with ATF (to simulate hot MT-90 plus save a few $$) and the pressure was fine.
 
So if I switch to Redline MT-90 can I just drain the old 80/90 out or do I have to flush out the trans somehow before I add the Redline? How much does a TR3 gearbox Non OD hold? Thx Karl
 
karls59tr said:
So if I switch to Redline MT-90 can I just drain the old 80/90...
Click to expand...

That's what I did. Messeurs Haynes & Bentley say it holds 1.5 pints -- since they are British those may be Imperial pints, still less than a US quart.
 
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