Hi guys,

I've done a search and I can't find a thread that discusses differences between early and late diff cages. I'm just wondering if anyone can tell me what the differences are between an A series diff cage and an A+ one? I'm in the process of rebuilding a gearbox and it looks like the diff cage is stuffed. I can find new A+ ones on the usual suspects and am wondering if there were any changes made along the years? It also appears that someone has done a quick rebuild on this box before me as there is still a lot of life left on the baulk rings and the spider gears etc. I'm assuming they put it back in the car and it was noisy and jumped out of gear and then it was put aside. Everything span freely before I started disassembly.

Diff cage - the better side:


Layshaft is stuffed:


Anyone have a good spare 2nd gear they want to sell me / give to me for free ? (to suit 4 synchro remote change box, 14mm mainshaft - box #22G846 (same as a 1128)):


Does anyone know how much gap there should be between the 1st/2nd shift fork? Mine is mainly worn on the left side (i.e. shifting into second or someone has left their hand on the stick while driving). I can't find easy reference to this in my manuals. 3/4 is very tight and this is definitely looser but I don't want to just go and throw parts at it if I don't have to:

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"In two years time your car will be like a lady's clothes, out of date, my car will still be in fashion when I am dead" - Sir Alec speaking to Pininfarina

A+ have little tangs on the thrust washers that stop the cage getting chewed up when the planet gears spin
http://guess-works.com/Shop/Parts/display.htm?id=186

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About .010" clearance in the fork is correct when new.
I believe some folks in UK have been known to squeeze old ones in a vice to close them up. Beware these bronze castings are brittle and this can crack them. If tempted, do a crack test afterwards.
Regards the diff hemisphere, it's easy to mod the A series one for the A+ tanged washers. Use a file or carbide burr.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks for the answers guys. Timmy / Doc, I was looking to throw out my old A series diff cage and replace it with a new A+ type. I just wanted to make sure the overall dimensions were the same so it'll bolt to my existing crown wheel and fit within my casing. If just the diff thrust washers need changing, that's fine.

Thanks for the info about the shift fork. I'll get the micrometers / dial gauge out and have a look. I wouldn't consider trying to squeeze it together in the vice. If needed, I'll drop some coin on a brand new one.

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"In two years time your car will be like a lady's clothes, out of date, my car will still be in fashion when I am dead" - Sir Alec speaking to Pininfarina

There have been problems with new aftermarket MK 2 forks. The dimension from the radius to the shaft hole too great. Need grinding to fit so doesn't bind on assembly.
Solution- buy a MK 1 fork, trial assemble to case. if it rubs on the case just sand it to clear. Depends on the casing.
Don't shorten the fork there is no need.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Is this still a valid option for my mk2 s 4spd syncho box? No other mods needed? The 4 spd syncho 1/2 selector fork one is unavailable again.

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1970 Mk2 Cooper S under restoration

Keith Calver has had the selector forks remade, if you can afford one and wait on shipping from the UK.

https://www.calverst.com/webshop/gearbox/

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ex-NSW Police 1970 MK II Cooper S
VMCI #43

Thanks Doug. I saw that option, but was wondering if they have the same problems Drmini was talking about above ? They too seem to have a problem necessitating the use of a 5/16 locating bolt (supplied). Didn't you use a modified 3spd syncho one in you last build ? Any problems ?
I have finished dismantling the 'box and have purchased a full set of "quality $$" bearings/baulk rings/layshaft etc etc to go with the quaife and centre pickup. Just need to clean everything and get the 1/2 selector fork, then re-assemble. First time reconditioning a mini gearbox in all the years of mini ownership (I have done a Alfetta Gt transaxle)

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1970 Mk2 Cooper S under restoration

ausdino PM sent.

Just a reminder, I have a genuine Leyland 22G889 1st & 2nd Speed Selector Fork in my for sale.