Moss gearbox easy(?) oil leak fix?

[No Quarter]

I've spent almost all my car fixing years on automatics, so clucthes and manual gearboxes are new to me, so bear with me...

My Moss gearbox has a slight oil leak at the back, and I want to replace the gasket. But I worry about all the axles and gears falling in a pile inside. The Service Manual F.7 talks about a dummy countershaft which I of course don't have.

So has anybody tried just replacing rear gasket. Right now gearbox is attached to engine, but not installed in car. If I remove speedo cable drive, universal joint flange, the plate C857 and the 7 bolts, can I then just pull plate backwards? And the two axles/shafts sticking out, will they stay in place in the gearbox or should they come out with the plate?

Any videos?

[JerryL770]

I don't have experience of this but my thought is that you would be best to separate the engine and gearbox and then stand the gearbox on the bell housing face. This way, taking the plate off the rear (now top) of the box should prevent anything from falling out - assuming no internals are secured in some way to the cover.

[bitsobrits]

Are you sure it's the rear plate gasket and not the rear seal? I'm not sure, but I think the rear seal is replaceable without removing the rear plate.

[mxke]

I had a leak at the rear of my Moss box and it was one of the o-rings at the rear of the transmission.

[No Quarter]

THe rear seal has been replaced, always do that.

Where are there o-rings at the rear?

A part of the leak I found out is the bolt holding the plate holding the two axles, it goes in all the way so oil comes out. There was a lock ring, of course not stopping oil, now I'm trying with copper ring instead. Has it prevented the leak, can't honestly say...

Ideas welcome

[mxke]

There are two o-rings that seal the reverse shaft and the countershaft where they protrude through the rear of the transmission.

Circled in red is where the shafts protrude out and the other is the retainer that holds the shafts in place.


Circled in red are the two o-rings in question.

[JerryL770]

Mikael,

No one has answered the last question in your opening post.

It seems to me from reading the Gearbox manual, that the laygear countershaft and the reverse gear spindle are somehow secured to the rear cover, probably via the locking plate (item 4) shown on the drawing on page F5. If you removed this first, it may be possible to remove the rear plate, leaving the countershaft and reverse gear spindle in place. I would still recommend to do that with the gearbox separated from the engine and stood on the bell housing front face. That way, gravity will not be trying to pull the gears out of line when you remove the rear end support of the shafts and the shafts will continue to hold all the needle roller bearings in place. You may need 4 hands to prevent the shaft seal rings sticking to the cover and pulling the shafts up!

There being o-ring (I think) type sealing rings on the shafts where they fit in the rear cover, I would probably fit new ones and be very careful how the rear cover goes back over those rings to prevent cutting them. Maybe making a small chamfer to the inside edge of the holes in the cover would be good, if not already present. Hope that helps.

[No Quarter]

Thanks for input from all. I'm a bit late in reading and answering, because I don't get emails about new posts here, even though I did tickmark "Notify me when a reply is posted", not sure why

During that time I've had maybe 10 iterations of drying off and testing stuff, to see if it might come from somewhere else. To skip to the solution, the leak came from 2 bolts, the one holding the plate fixing the two axles, and the lowest bolt in the rear plate. I had both of them out, dipped in RTV Black, replaced lock rings with copper rings, and now it's bone dry

So I don't have to take the rear plate off on this occasion, and if I had, I would probably still have had the leak afterwards.