When you change your engine oil you are also changing the transmission oil,Its all together.

On the Savage, the engine oil IS the transmission oil.

And that tells us that transmissions don't need transmission oil,......that 30 wt motor oil works perfectly fine in transmissions too. But those of us that worked in the the transmission/gear box industry already knew that. And thats why the oil threads that are so serious to some, are so humourous to most of us.

2 stroke bikes need to have there transmission oil changed, as the engine oil is in the fuel/or injected

Back in the 60s, in the summer we had hi speed gear boxes on new harvesting equipment running so hot the 90 wt gear oil was smoking out the vents. The warranty fix was to drain the 80-90 wt, then install 30 wt motor oil. The boxes never smoked again, the fix was made permanent by the gear MFG, and the oil spec sheets were changed to 30 wt.

But yet, most gear boxes still run 80-90 wt oil

Charon wrote on 11/04/09 at 14:17:04:


Originally, all motorcraft, be they 2, 3, 4 wheelers, had gearboxes separate from the engine.
So engine oil was separate from gearbox oil.

The story about the Austin Mini is correct.
Whereas the Austin Minor had a 4 cylinder engine mated to a traditional gearbox and rear wheel drive (so engine and g/box would be separate)
the extremely tight space available within the Mini's engine bay was such that the solution was to fit the engine transversely, and design a special gearbox that was integral to the oil pan (sump in English)
Thus, the first truly front wheel drive, transverse engine system was born.
Competitor marques (such as Renault) insisted on a longitudinal engine and a transverse gearbox... definitely a more primitive design.

Motorcycle gearboxes, unlike automobile gearboxes, have sequential gear changing; you must go through all the gears whether going up or down.
Cars & Trucks have the typical "H" layout which allows to shift 5th-3rd, or 4th-2nd... not possible with a sequential system.

Most motorcycles today have a wet clutch, so "engine oil = gearbox oil" is the paradigm.
Ducatis, Guzzis, BMWs, even Harleys have a dry clutch so you will have separate engine and gearbox oils.

I have never considered a 30w oil in a gearbox; both my truck's instruction booklet, and that in my wife's car insist on 80/90 oil.
It is unlikely that I may come across any 30w oil, but a cheap 15/40 could be an interestnig idea...

bill67 wrote on 11/05/09 at 08:25:21:


That the same manufacturer that made it near impossible to get at the spark plug unless you remove the fuel tank?