MD11C: MSB gearbox manuals?

[Dymaxion]

Hello, would anyone have info regarding the older MSB gearbox that Volvo used on MD11 motors? Mine is a little whiney in reverse, quiet in forward so it may be rebuild time. Only drawing I've found so far is for the cone clutch/lining. Which will be useful if the lining is done. And... when sailing the gearbox should be put in Reverse to avoid wearing out the lining? Or is that a myth? Many tx.

1980 Sabre 34-1
Campobello Island, NB

[deblen]

Hello neighbour. Check tag for gearbox model.
Probably a MS2....
http://fybmarine.co.uk/pdf/Gearbox-o...ntity-type.pdf


Cheers/Len

[DougR]

The MS and MSB gears were a little “whiny “ in reverse because the power path goes across two idler gears that are straight cut and you are hearing the gear noise. In forward these gears are still turning, but not carrying any load, hence quiet.

You are correct, if you wish to lock the prop when under sail the transmission should be put into reverse. This causes continuous pressure of the cone into contact with the brake lining cup and avoids slippage of the cone and cup.

Putting the gearbox in forward to lock the shaft may allow slippage between the forward cup and cone and thus wear may occur.

I think you can find a workshop manual for the gearbox in PDF format out on the internet.....

[deblen]

https://www.plaisance-pratique.com/I...120_manual.pdf

[DougR]

So the OP titles his post by saying “MSB gearbox manuals” ....then he states that he actually has an MSB gearbox, so why would one try to convince him that he has an MS2 gearbox??

[deblen]

Originally Posted by DougR

So the OP titles his post by saying “MSB gearbox manuals” ....then he states that he actually has an MSB gearbox, so why would one try to convince him that he has an MS2 gearbox??

Guilty of assuming. My bad. /Len

[Dymaxion]

Hello and many thanks for the info! Now I understand why the different noise levels in F/R gears! My ears tell me that a fresh change of oil would be a good thing, can't hurt and I'll have a better idea if things are going bad inside. No complaints about having the detailed MS2 manual on hand, I'm a pack rat for such things and you never know what the "next boat" will bring. Did like the conventional dipstick on the MS2 box, and looking at that huge brass nut for the MSB oil fill makes me wonder what could be done in that regards with a little creative machine shop work. DougR, saw your mention of swapping out the 8 needle bearings for fabricated oilite ones, I have a small metal lathe and may get back to you on that task in the fall. Thanks again all, Tim

[DougR]

Workshop manual available at varen4u.nl/pdfs/volvo/mono shift-msb.pdf