Differential Identity?

[amgrave]

I have come across what looks like a BMC differential but the I.D. on the crown wheel and pinion set says 3.7:1 yet all the ones I have come across have always had the teeth numbers stamped on the crown wheel as xx/xx but this one has not got the stamp. Another strange thing is the tooth count is 10 on the pinion and 37 on the crown wheel and I can't find any reference to these numbers in relation to a BMC differential. Has anyone seen this before or can shed some light on it, I'm worried someone has fitted a cw&p set in a BMC housing and it might cause problems or not fit. I has got MOWOG on the body casting and bearing straps and has 8 fixing holes and no oil filler plug.

[philthehill]

[frame][/frame]

http://www.ebay.co.uk/itm/MG-Midget-Spr ... 2ee68c90b7

If I recollect correctly there was a BMC Special Tuning option of a lower ratio diff than the 3.72 listed above. This special diff was mentioned with the ratio on this forum not so long ago.

[bmcecosse]

Have you counted the teeth - to make sure someone hasn't just stamped it to 'improve' the value of an otherwise very ordinary final drive.... Also check it's not a Marina unit.

[amgrave]

The seller has confirmed it is a 10/37 by counting the teeth but I still can't find any info on this. Thanks philthehill I have seen a copy of that on the website but yours has a bit more info. The ATA numbers suggest it is a van carrier with special CW&P fitted and if the markings are correct 3.7:1 instead of 3.72:1. By the way that's the one.
BMC no numbers on the CW&P other than the ratio, no tooth numbers but your concern is why I posted this.
Thanks for your replies.

[philthehill]

The Marina/Ital rear axle ratios were/are:-
4.55
4.1
3.9
3.6
3.3

[bmcecosse]

Check if a Minor halfshaft fits...

[amgrave]

That's a good point. The seller still insists he has counted the teeth correctly and it's 10/37. He reckons he was going to fit it to his moggy pick up but never used it.

[amgrave]

Can someone remind me of the size and spline count on the the diff end of the half shaft please, looked at the workshop manual but no mention of half shaft size.
Thank you.

[philthehill]

Amgrave
A Morris Minor axle shaft has 10 splines.

You have a PM.
Phil

[amgrave]

Thanks Phil, I have replied to your PM.