Morris Minor Owners Club

I have a good spare smooth case gearbox. It is a bit sloppy in the shifting.
At the rear of the box, I measure .080 movement in the synchronizer. Here is a picture with a nylon wire tie pointing to the area of fore and aft movement. Second picture is the synchro pushed to the rear.
It seems like that is a bit much movement. Will thrust washers or shims tighten that up?
David[frame][/frame][frame][/frame]

Worry more about the 1st gear teeth on the laygear, and the wear condition of the dog teeth on 2nd gear.

Is there a source for the brass synchro cones attached to the gears, or do I have to buy the whole gear?

Syncro cones are not attached to the gears - that's the whole point of them!! So yes - they are available, but I believe there are some very poor quality items around..........and the design changed slightly - so I'm not sure the modern cones can be used in the early smooth gearbox. Maybe they can - I just don't know !

I've taken the smoothcase apart and here's what I see. The gears 2, 3 &4 have brass synchros attached. They are dimpled into a corresponding hole in the gear.
The ribs on the rings are worn pretty smooth. Just like the dog teeth, there is greater wear on 2 than on three, and even less on 4.
I've taken a center punch and put my own dimples into the rings where the ribs have worn. That will raise a little metal, and do the job that the ribs did. That's my theory.
After I did that, I reduced the .080 movement to .040.
I'm waiting for some parts to cross the pond and then I'll put it together and see what happens.
The later synchro rings have ears on the outer rim, so they won't fit the rest of the parts.
http://morrisminorspares.co.uk/shop/pop ... hp?pID=220
I don't see the rings listed in the parts book, or any online supplier for the smoothcase gears. There is a reference in the workshop manual to the rings, calling them "cones."
There is an outfit over here that puts the 1275 guts into the smoothcase.
http://www.quantumechanics.com/categori ... ex&catid=6
This picture shows the large dimples that fix the ring to the gear and my dimples on the worn segments.[frame][/frame][frame][/frame]

So the confusion is that these are not 'syncro rings' - they are just the wear surface on the gear - on which the syncro ring will rub to syncronise the speed before the dog teeth engage. The syncro ring for 4th gear never takes much wear - so you can use that to compare the wear on 2nd gear ring which will be by far the worst. I'm surprised the old rings are not available - have you tried a Mini supplier? The newer rings are describd as 'baulk rings' - I'm actually just wondering if I have a new old one somewhere in my parts 'midden'........

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4th gear syncro on the input shaft showing the "dimple receptors".


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showing the female "cone receptor" on the mating hub


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Other gears don't have "dimple receptors."


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relative wear on the ribs, 2 and 4th syncros.

This is different to how I remember it then - but it's a very long time since I ever opened up a 948 gearbox...... The dog teeth on 2nd gear look quite badly worn......

New gears are priced out of my range (so says my wife)
and there is no history of the first 50 years of this gearbox's life.
It'll be several weeks before I get this box installed, but I'll update when I can.

What does 1st gear - and the matching teeth on the laygear look like ?

Serviceable. I don't spend a lot of time in first gear.[frame][/frame]

Ohhhhh - that's very good! It's the crunch engaging that wrecks them !!

A setback!
Some parts have arrived. I drove out the tailshaft bushing, and pressed in a new one. Heard a loud snap.
What did I do wrong?
Is that drilling supposed to be there? (The drilling at the end of the shaft. I stop drilled the crack to keep it from spreading.)
I'm going to try to have it welded up.
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Oh dear..... Should weld ok -or just fill the crack with epoxy and put a good clamp round.

I located a used tailshaft housing, and have put the trans back together. It looks and feels nice and tight.
What I could not find, however, is specs on clearances (with the exceptions of the front and rear bearings.) The thrust washers come in various sizes, but where does it say what to measure in order to determine the proper thrust washer size?
I'm going to swap out the trans that is in the car now, and O/H that one, too.

Here's an update.
I've got my gearbox with the dimpled syncros installed, and I'm REAL happy with the difference. Things seem to feel a lot tighter when shifting. First and reverse are 100% quieter. Shifting is smoother, including downshifting.
I've done a quick autopsy of the removed gearbox, and found the bushing between the first and third motion shaft was the wrong size. It had .025 clearance. It was obviously the wrong bushing and just pounded in.
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I'm going to rebuild it with my dimpled syncro method, but I'll be more aggressive in my dimpling this time. I lightened up on dimpling 3rd and 4th syncros the first time around.
I had contemplated upgrading to the ribcase to get better shifting, but I decided the ratios may be a bit much for my 948 engine and 3.9 rear end. As it is with the smooth case, the ratios are just fine.[frame][/frame]

Good result -well done.

I have two cars, a 59 convertible and a 61 Traveller, (The convertible is for sale if anyone is interested.)
I picked up my spare smoothcase transmission on Ebay, it's the one referenced above last month. The story was that it was professionally overhauled many years ago and never installed. You know what stories are worth.
The spigot bushing between the 1st and 3rd motion shafts (pictured above) was glaringly obvious when I took things apart.
My Traveller arrived two months ago, and I'm into the transmission now. The story was that the car was "restored' several years ago before coming to the US. Another story of questionable value.
I found the first motion shaft a little sloppy before dis-assembly, and found the same spigot bushing situation as above, although this one was a nice fit in the shaft. Very sloppy clearance of about .025.
That's three transmissions and two bad bushings in the same place.
There isn't a question here, just venting.