LSD-spec Gear Lube in non-LSD Gearbox

[EvoStevo]

Hi all. I have a 1989 BMW 325is and year or so ago I bought a couple quarts of Red Line MT-90 gear lube to fill my diff with once I replaced all the seals and stopped it from leaking. Well, I never got around to that and now it's time to change my transmission fluid. I was wondering if it would be ok to use the gear lube I have (which says for use in limited slip differentials on the bottle) in my transmission. Thanks.

 

[Colt45ws]

I wouldnt. I believe Redline makes a gear oil without LSD additive for transmissions.

 

[SuperDave456]

I don't think it will matter if you have LSD fluid in a non LSD differential.
I know that Amsoil says that if you put their stuff in and your differential begins to chatter put in some of their Slip Lock and that will quiet it, but it is not normally needed.

 

[Colt45ws]

Originally Posted By: SuperDave456
I don't think it will matter if you have LSD fluid in a non LSD differential.
I know that Amsoil says that if you put their stuff in and your differential begins to chatter put in some of their Slip Lock and that will quiet it, but it is not normally needed.

I think he is talking about putting gear oil with LSD additive in his transmission.

 

[EvoStevo]

Originally Posted By: Onmo'Eegusee
Originally Posted By: SuperDave456
I don't think it will matter if you have LSD fluid in a non LSD differential.
I know that Amsoil says that if you put their stuff in and your differential begins to chatter put in some of their Slip Lock and that will quiet it, but it is not normally needed.

I think he is talking about putting gear oil with LSD additive in his transmission.


Yep, that's what I want to do. So you think the LSD additive will be bad for my transmission? I was hoping the LSD-spec stuff superseded their regular MT-90 and you could use it interchangeably. Oh well. This will all be moot though if I go home and find out that my transmission actually takes ATF (as some BMW manual trannies apparently do).

 

[JHZR2]

Ive heard that the LSD adds harden the surfaces. However, this is related to diffs, the metals in transmissions may differ. Why not contact redline? They are pretty good with responding.

 

[LoneRanger]

In a manual transmission with synchros, you generally *do not* want the limited slip friction modifiers.

 

[Steve S]

MT 90 IS A TRANS LUBE?

 

[m37charlie]

MT90 is a trans lube, not a diff lube.
Look at Redline's site carefully, they have a whole page dedicated to BMW recommendations including transmissions. Which range from ATF to MT90 viscosity range.
Generally speaking I would not recommend putting GL5 gear (differential) oils in manual transmissions.
http://www.redlineoil.com/news_article.aspx?id=13

Charlie

 

[PT1]

Call Dave at RL...he will know.

 

[ryan2022]

Personally,

I wouldnt run anything that wasnt GL4 rated in a manual transmission.

This would rule out most of the GL5 oils, and ones that were meant for limited slip.

 

[tdi-rick]

MT-90 is NOT a hypoid diff lubricant, it's a GL-4 rated manual transmission lubricant.

FWIW, LSD fluids generally don't work with synchro gearboxes, the friction modification is all wrong, with the LSD friction modifiers generally reducing the synchro clutch/cones ability to function correctly and match speeds.
[edit]The only fluid I can think of that works as a very good manual trans lube and supposedly works in LSD's is Neo's 75W-90HD.

LSD fluids work fine in race 'dog boxes where there aren't any synchros to worry about.
Castrol's SAF-XA 80W-140 has a high treatment of Sturaco 7098, a friction modifier required by Dana for their LSD's, yet it is the specified lubricant for the Holinger 6 speed used as the spec 'box in Australian V8 Supercars.

 

[mechtech2]

I'm not sure what product you have.
Normally labeled Redline MT90 is a great manual trans lube.
But yours says it's for limited slip use?