Morris Minor Owners Club

Has anyone had problems fitting a late type diff with the level plug to an earlier axle ? I have just tried and found that the flanges on the bearing caps foul on the inner casing.

The later 4.22:1 diffs don't have the level/filler, it's in the axle casing along with the drain. The earlier 4.55:1 diffs do have the plug. Does your axle casing have both filler and drain or just the drain?

I'm actually fitting a 4.9 which has a level plug in the casing into an axle with a level and drain plug.

I thought you were asking if a later diff fitted to an earlier axle, but your last post suggest an early diff into a late axle or have I read it wrong, or are you talking of an even earlier type of axle. and where has the 4.9:1 come from as I though the lower ratios were 4.55:1 and 5:375:1

I thought it was the later type diff but 57 traveller informs me otherwise. I also have the same problem with a 5.3 diff with a filler plug. I'm not really bothered about which bit is early and which bit is late , I just want to fit them together. I can easily file down the flange/ grind out the casing just not sure which to do yet.

I'm confused.

Why do you want to put a 4.9 diff in a Minor in the first place[or do you mean 3.9].I would think a 4.9 will let you climb mountains but will do nothing for M.P.G.
Wanderinstar.

If you look carefully on the rim of the crown wheel you will see
the figures which denote the number of teeth on the crown wheel
and the pinion. i.e. 38/9 etc. What are they????

I'm fitting 4.9 diff to my racer , not a road car . BMC diffs are fitted to lots of historic race cars because BMC did such a wide variety of ( supposedly) interchangable diff ratios from 3.4 to 5.3. I have 4.9, 5.1 and 5.3 for mine.
However I have found this minor ( no pun intended) problem fitting some of the ratios . I merely raised the subject to warn others that not all difs wil fit all axles without mods , which may not be obvious when you're on your back under the car.