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Lube in OD gearbox

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Dave_W

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I've got a '70 MGB with overdrive. I've drained my OD gearbox and changed the filter, etc. Now I'm about to refill it. I know from experience with motorcycles that certain lubricants don't work as well with wet clutches due to some of the friction modifiers. The OD has a cluth in it. Is this a problem? What oil should I use?
 
I use Valvoline 20W50 racing oil in the transmission (mine is an OD as well), same as I use in the engine.

John from Quantum Mechanics (known transmission/OD rebuilder) recommends 30 weight non detergent motor oil.
 
You'll get as many answers as replies to this thread. I used to use 30W ND but now use Redline MT-90 Synthetic. Couldn't be happier with the Redline. Yep, synthetic in an overdrive gearbox. It's not the "super-slippery" kind.
 
Thanks for the replies. My first thought was to go with the 30 non detergent, but maybe the 20-50 would be better given the temp extremes here in Iowa.
 
The gearbox in my B seems to shift fine, and the OD works well, with the 20W50. Besides, this way I only need to keep one kind of oil in stock for the two of them.
 
Good point on only having to have one kind on the shelf.

I also read a tech article on the Moss website about the need for ZDDP in the engines. Does this cover that?
 
The Valvoline VR-1 racing oil (20W50) has a higher zinc content and seems to work well with these engines. Was recommended to me by my engine builder (for my Sprite) and it's reasonably easy to find locally.
 
OK, good. Thanks for the tip. I'll look around here and see what I can find.
 
Hey Dave! I'll bet there's more than one way to skin that cat, but . . .

I only use the factory-recommended 30wt non-detergent. I've had trouble using other oils - though others have evidently found success. Good luck, and Safety Fast!

Phil
 
VR1 is a really expensive way to fill a gearbox. It contains all kinds of stuff the gearbox doesn't need. I'd go with either 20W-50 or SAE-30 ND, the latter being much harder to find but recommended by Quantum Mechanics.
 
I use 20/50 in the B, the same oil I use in the engine and have never had an OD problem. I agree though, that gear boxes don't need a high detergent oil. If you prefer a 30W non detergent oil, some convenient stores sell it under their own brand name. Rare to find ND anymore in an automotive store. PJ
 
I think I've pretty much settled on going with the 30 ND oil. It's readily available at Walmart around here in one of their store brands, also at most farm stores. (I'm in Iowa)

After ruining a motorcycle clutch apparently due to the friction modifiers in some oils, I'm concerned about the clutch in the OD unit. Don't want to have to tear that thing down.

Thanks for all the replies.
 
Motorcycle wet clutch isn't really equivalent to the cone clutches in the Overdrive.

The original manufacturers recommendation was always 30W non-detergent motor oil.

However, I have ignored that on many occaisions and gone with regular motor oil, 10W40 Valvoline, etc., with no apparent consequences.

After having problems after each oil change in my MGC GT (solenoid always would hang up in gear for the first time or two) I changed to Mobil-1 and never looked back. I think I used 10W40, but it was so long ago I don't remember.

C Ya,
Mark
 
I use Royal Purple 20/50 in mine. Have for years with no problems. Before I went to the Royal Purple I always used Castrol GTX 20/50. Never a problem with that either.
 
A friend smoked two OD units (one a brand new one) using synthetic in his gearbox on the track, Beware!
 
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