MorganExp

Morgan +4 Forum

Transmission Rebuild

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Button Bill B
Seattle, Washington, USA   USA
I am looking at the same assy as Your picture. As I recall The balls and plunger are pretty stiff. I used a rubber mall to move the gear. I have a Jag/Moss Box apart. I will try to assemble it without balls or springs or plungers and take a picture of it. But it is bedtime. So it will be tomorrow morning PDT.

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DuncanCharlton Avatar
DuncanCharlton Duncan Charlton
Elgin, Texas, USA   USA
1931 Morgan 3 Wheeler "Gwenda (Sold)"
1967 Morgan 4/4 "Toly's Car"
1967 Unknown Unknown
1970 Mini Countryman    & more
Barrie,

If I remember right, you should be able to remove the hub from the main shaft while it is assembled and with neither first nor second engaged -- that should leave the plunger in the retracted position. With it off the shaft the plunger and ball should fall out of the hole in the inner portion of the hub. Plungers are (or were, at least) available in different lengths. That said, it's simply been too long since I had one of these apart for me to remember whether a problem engaging first gear would also be a problem with engaging second gear.

DuncanCharlton Avatar
DuncanCharlton Duncan Charlton
Elgin, Texas, USA   USA
1931 Morgan 3 Wheeler "Gwenda (Sold)"
1967 Morgan 4/4 "Toly's Car"
1967 Unknown Unknown
1970 Mini Countryman    & more
Rob -- the flat spot is something I've never seen, even on the high-miles gearbox from our '71 Plus 8 (if it was the original gearbox -- and I think it was -- it had at least 190,000 on it when I opened it up). I wonder if it was filed down and polished smooth in order to fix a problem with gear engagement. If the rest of that end of the plunger is still rounded and it engages as it should, perhaps it does not strictly need replacement, but replacement seems like a good idea in order to keep the plunger doing the job it was intended to do (it would be bad news if you selected two gears at once while moving) -- but obviously the overall length of the plunger must be correct for it to work in the end.

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Walden MG-Morgan Avatar
Walden MG-Morgan Barrie Walden
Falmouth, MA, USA   USA
Bill,

How far is the ball down when in first gear (see photo). If it’s not far enough down it will not able to move first gear backward.

Barrie


Attachments:
Jaguar Gearbox (8).jpg    56.1 KB
Jaguar Gearbox (8).jpg

Button Bill B
Seattle, Washington, USA   USA
Crudely measured .5".

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Walden MG-Morgan Avatar
Walden MG-Morgan Barrie Walden
Falmouth, MA, USA   USA
Rob, Duncan, Bill

My gearbox second synchro ball falls down a less than 0.04 (~1/32”) when gears are in neutral position. If my test is actually right, it will not be able to move enough for first gear use. The ball seems to be able to move slightly so the plunger as probably stuck.

Barrie

Button Bill B
Seattle, Washington, USA   USA
I use a 50:50 mixture of acetone and ATF to get things loose. Mix some up and put in a plastic bottle that You can squirt a bit into anyplace You can get at.

Or/And:

Get the Main Shaft and gears out of the box and use a press.

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Walden MG-Morgan Avatar
Walden MG-Morgan Barrie Walden
Falmouth, MA, USA   USA
Rob, Duncan, Bill

I used Acetone and ATF for two days as you suggested Bill. The ball looks good but I don’t know about the plunger. I’m beginning to think the plunger is working correctly.

I can think of two different things that may be a problem. 1) Fred Sisson’s Bedside Reader says the 1-2 syncro ring is the only one position that will allow it to work properly. Mine is in the right place. 2) The
first gear teeth in the mainshaft and layshaft may have problems. The only one I can see does not look too good. Is the layshaft is the same way, this could be why I can’t use the first gear.

What do you think?

Barrie


Attachments:
Jaguar Gearbox (10).jpg    45.6 KB
Jaguar Gearbox (10).jpg

Jaguar Gearbox (11).jpg    56.2 KB
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DuncanCharlton Avatar
DuncanCharlton Duncan Charlton
Elgin, Texas, USA   USA
1931 Morgan 3 Wheeler "Gwenda (Sold)"
1967 Morgan 4/4 "Toly's Car"
1967 Unknown Unknown
1970 Mini Countryman    & more
Barrie,

Those main gear teeth don't look any worse than those on my former Plus 4 race car.

Duncan

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Button Bill B
Seattle, Washington, USA   USA
I guess I would dress up the damaged teeth with a fine mill file. Maybe put some of that blue stuff that Machinist use to insure the damage is not causing interference problems. On this I think You need to talk to a experienced transmission guy.

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DuncanCharlton Avatar
DuncanCharlton Duncan Charlton
Elgin, Texas, USA   USA
1931 Morgan 3 Wheeler "Gwenda (Sold)"
1967 Morgan 4/4 "Toly's Car"
1967 Unknown Unknown
1970 Mini Countryman    & more
I doubt a file will do much. Those are hardened teeth. I suggest using an abrasive tool of some sort instead, but you really don't want to cut through the hardened outer metal unless you're prepared to case-harden the teeth again.

Duncan

Button Bill B
Seattle, Washington, USA   USA
Damn if You do and damn if You don't. Maybe a touch up with a Dremel tool will allow the gears to mesh. If that is the problem. Then find a first gear. I might be able to help on this. Don't know yet. I know a rebuilder that would have one. But He is a "Rebuilder" does not sell His parts.

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Walden MG-Morgan Avatar
Walden MG-Morgan Barrie Walden
Falmouth, MA, USA   USA
Bill,

I’m still using Acetone and ATF but there doesn’t seem to be any change. I re-checked the synchro ball down and I think it may be less than 1/32” but it’s so hard to test. I looked at my gear teeth a second time and I couldn’t be sure if they were bad or not (“main gear teeth don’t look any worse than ---“ Duncan). I guess I have to send it to a gearbox rebuilder.

Can you send me your email address so I can reach you if I need your help on the first gear problem.

Barrie
barriebwalden@gmail.com

61highline Tim Remesal
Santa Rosa, California, USA   USA
1961 Morgan Plus 4 (+4) "61Highline"
Ive got my late 50's TR3 all syncro transmission being rebuilt to put in my 61 +4 Highline .
What problems will I have to deal with relating to foot space ie gas peddle ? My car is down to the frame . Have any of you done this conversion of late?.
Thanks , Tim

DuncanCharlton Avatar
DuncanCharlton Duncan Charlton
Elgin, Texas, USA   USA
1931 Morgan 3 Wheeler "Gwenda (Sold)"
1967 Morgan 4/4 "Toly's Car"
1967 Unknown Unknown
1970 Mini Countryman    & more
You will lose some foot room, but I can't say how much. I have sat in a 1952 Plus 4 with a TR3 gearbox and MG hanging pedals but unfortunately I don't recall how much foot room remained. I do remember that the shifter knob was well up under the dash and not so easy to reach.

Duncan

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