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MG Midget and Sprite Technical - Differential query

The other day my Frogeye imitated a Rolls Royce, it didn't break down, it just failed to proceed. The culprit is the diff. Specifically the pinion gears (see photo). The problem is finding new ones. Moss doesn't carry them anymore. I've got an old 4:22 one that I could cannibalize but I'd like to keep it complete. Or I could try to find another 3:9 to replace the one that broke. The question is, does anyone know who might have these gears available?

Martin Washington


Have you tried Mini Mania?

Also a post on the US forum SpriteSpot may work.

You could always try getting a used differential with an OK pinion and rebuild that with seals and bearings if you cannot get the correct replacement pinion.

In the UK I would try asking Hardy Transmissions or Peter May Engineering who list a 3.9 crownwheel and pinion for sale:

For rebuild advice see: (Norm Kerr in USA who posts on here too)

& (Mini Mania)

Hopefully more advice or offer of the correct diff will come along in a minute!


M Wood

Is it the pinion gear? The photo shows the sun and planet gears. These are the same in all the diffs so you could use them from the spare 4.22.
Bob Beaumont

Keep an eye on ebay there are always pats guys with stuff there. Contact them to see what they have left on the donors. Also an outfit in Syracuse NY I got an NOS fuel pump from that were deep into the real thing not just selling repro parts.
Bob Ketcham

I;ve got a busted diff(crown and pinion) that I can canibalise....
Onno K


Minimania doesn't have them anymore but I'm looking at other options.


Yes, it's the planet gears but all of the catalogs and manuals call them differential pinions.


I may take you up on your offer if I can't find anything.

Thanks for all of the input.
Martin Washington

Martin. Scour the ads. There must be plenty of used diffs out there. Pretty well any one will do, Midget, Minor, any ratio as you dont need the CW&P.
Fit your crown wheel and reassemble in your housing/pinion unit.
Or buy a limited slip and have oodles of fun!
Andy Pie C


I've thought about a limited slip diff but my wheel barrow of money isn't that big. But it would be nice.
Martin Washington

Then the real budget option is also available Martin - weld it up!!
Andy Pie C

Martin, my MGOC catalogue and my Moss catalogue has them listed correctly:

Sun wheel: ATA7037
Thrust washer: ATA7039
Planet gear: 2A7015
Planet gear thrust washer: 2A7062

I think you need to look at the right catalogues :-)

PS check the numbers in case I've made a typo error.


Nick Nakorn

Parts are on order from MGOC. I had started looking here in the states since there is an ocean and a continent between myself and Britain but with the convenience of the internet and international shipping, I should have gone with the obvious. Interesting how Moss UK and MGOC have these but Moss USA and Minimania don't have them

Anyway, thanks for all of your input, I'll be back on the road soon.
Martin Washington

This thread was discussed between 30/04/2014 and 03/05/2014

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.