I plan to fully rebuild a 4 sycro remote box. This box is for my 1360 BMW twincam build, it'll have a Quafie ATB diff with a 3.1 FD and the engine will be tuned for torque. So with all that in mind.
I'll have a heap of questions but for now I'll only ask five. Currently I have striped as much out as I can and I need some guidance with a few things.
(1) The drain has striped out so what are my options

(2) How do I and is it nessary to remove the speedo drive

(3) Should I replace the driveshaft output bushes (the bearing thingy)

(4) The top and bottom bushes in the diff housing for the gear selector shaft, the shaft seems to move around a bit in them. How tight/loose is the shaft meant to be, should I replace these

(5) cleaning up the threads on everything, what taps and dies do I need And I'm assuming I leave all the studs in where they are correct?

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Respect mine and I'll respect yours.

You can get plugs for stripped drain threads here, but you will probably be better off with a helicoil. I have never used a helicoil, but i have one on my gearbox in the same place, and it works well.


It should slide out from the side once you have removed the cover plate. You shouldn't need to touch it though.


Only if they're worn, I'd say. I've never seen them wear down before, but they may well do.


They shouldn't be tight, but they should move freely with little sideways movement. I'm not sure what you would do to fix that.

Can't say off the top of my head - I'm not good with thread sizes anyway.

For the drain plug I helicoiled it - have some left over if you need it.

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

You can take the studs out, it makes cleaning the gasket surfaces easier. Its just time consuming.
You will need 1/4 and 5/16th and a 3/8 UNC finishing taps to bottom out the threads.

The studs will have UNC on one end, and UNF on the other.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

The 2 side cover bushes are usually worn- press new ones in then get them set up true in a lathe and machined to size for ~.001" clearance on your drive flanges or pot joints. If you leave them worn the seals won't last long before leaking.
These bushes are about .007" undersize when bought.

The 2 shift shaft bushes in the diff cover wear bad and should be replaced. I screw a 9/16" UNF tap in, then use a hammer and a bit of 3/8 rod to drive them out. You could also use a 14mm tap.

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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.

4/ you can just catch the side of them with a long drift, or use a slide bearing puller. Easy job

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did I tell you that I won a trophy?

Thanks for the answers so far.
Can I use selector shafts and knuckle joint parts from a 3 sycro remote box? It's only the gear clusters that are different correct Can you fit 4 sycro gears into a 3 sycro box, what is the difference between the two boxes

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Respect mine and I'll respect yours.

The knuckles and shift shafts they attach to are the same.
The selector shafts in the bottom of the box are not.
The 4 synchro case is wider inside, and machined differently. Can't fit 4 synchro setup to a 3 synchro case. Go find a Mink K/1098 Clubby box..

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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 Doc, also (I can never remember) can the gears out of a rod change be installed in a remote box (I think the answer is yes but I want to confirm for sure).

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Respect mine and I'll respect yours.

4 syncro gears are 4 syncro gears, doesn't matter what shift type

Except reverse idle gear, thats different. NLA I believe

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1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

Might be NLA new, but PM me if ya need a good s/h one.

The difference in the reverse gear is the groove position for the selector fork.

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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.

I have just rebuilt a box now it's stuck in either 1st or 2nd? I can still select 3 , 4 and R ..... What have I done ?

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Did you line up all the bell crank levers putting the selector shaft in?

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1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

Yeah I think so. I just had to replace 1st gear so I left all the selectors in.

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