Transmission oil

Fast Eddie · Mar 20, 2019

I’ve never really liked the idea of using ‘normal’ engine oil in the transmission (especially Silkolene, which breaks down quickly in my experience).

But the gear oil being shared with the clutch presents an added hurdle to ‘normal’ gear oil.

Think I might try this:

http://www.belray.com/product/sport-transmission-fluid/

Clive · Mar 20, 2019

Hmm - I had exactly the same thoughts but there have been quite a few posts where alternative oils have caused clutch issues. My conclusion is that I'm currently happy with the clutch action and if it gets messed up with an alternative oil then it could be one hell of a messy task to get it sorted so I will continue to use the recommended oil but change it on a more regular basis IMHO.

Fast Eddie · Mar 20, 2019

Clive said:
Hmm - I had exactly the same thoughts but there have been quite a few posts where alternative oils have caused clutch issues. My conclusion is that I'm currently happy with the clutch action and if it gets messed up with an alternative oil then it could be one hell of a messy task to get it sorted so I will continue to use the recommended oil but change it on a more regular basis IMHO.

I wonder if folk inadvertently used oil not intended for wet clutches?

Britfan60 · Mar 20, 2019

Richard 07 successfully uses Motul full synth in both. Based on his recommendation, I cowardly went with Motul full synth engine and blend for the tranny. Ah....not guts no glory. Had a nice silvery sheen when last changed.

richard-7 · Mar 20, 2019

Britfan60 said:
Richard 07 successfully uses Motul full synth in both. Based on his recommendation, I cowardly went with Motul full synth engine and blend for the tranny. Ah....not guts no glory. Had a nice silvery sheen when last changed.

Yup. Every one we know around here with a 961 have had great success.

Fast Eddie · Mar 20, 2019

Richard, which one?

Is it the Motul 7100 4T range?

Which weight?

Raphi · Apr 6, 2019

Fast Eddie said:
Richard, which one?

Is it the Motul 7100 4T range?

Which weight?

I had Motul 4T 7100 10w40 MA2 in my old engine.
Today I have Belray transmission... Both red color which makes it easy to distinguish from the engine oil, if you have any leaks.
With both of them I never had clutch issues!

Fast Eddie · Apr 6, 2019

Do you use this one Raphi?
I bought some to try but haven’t put it in yet...

Raphi · Apr 6, 2019

Maybe this one. I didn’t put it myself, it was Ollie. But if there is no other Belray transmission, it must be this one.

Fast Eddie · Apr 6, 2019

The 961 is strange in many ways though (as we all know), one such strangeness is that the gear oil is shared with the clutch and primary.

HD Sportsters are the same, and they allegedly have the same / similar gearbox.

The Belray I’ve bought is designed for HD Sportsters.

Britfan60 · Apr 7, 2019

Fast Eddie said:
The 961 is strange in many ways though (as we all know), one such strangeness is that the gear oil is shared with the clutch and primary.

HD Sportsters are the same, and they allegedly have the same / similar gearbox.

The Belray I’ve bought is designed for HD Sportsters.

From memory, my understanding is the 961 tranny is very much like or the same as the Sportster. I may go that route. Don't you use the same oil for the T140 in the engine and tranny, FE?

Fast Eddie · Apr 7, 2019

The T140 breaths through the primary, so engine and primary case oil should be the same. I use the Bel-Ray 10W50 V-twin syn that came out top in Comnoz’ oil testing in the T140 as it is compatible with wet clutches. I intend also to use it in the 920 motor I’m building for my ‘74 and may well try it in the 961 too.

I am running Redline lightweight shockproof transmission oil in the T140 gearbox at the moment. But with that oil, the shifting was improved with the addition of Molyslip.

I will try the Belray V Twin gear oil in the T140 too, I can’t see why it shouldn’t be good in that. But I won’t know until I try it I guess.

I like to standardise such things in my shed as much as possible, it makes life easier !

Transmission oil

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