Anyone have a Muncie M21 four speed going spare?

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Blondie69

CCCUK Member
Good evening
I'm looking for a donor Muncie M21 four speed. Something in a usable condition but ideally a functional ready to go.
My big block 1969 C3 has eaten the current Muncie 21. I understand they are rare but someone may have one sitting under a bench.
Thank you for your thoughts and ever hopeful ☺️
 
Roscobbc

Roscobbc

Moderator
Barb - there are two 4 speed Muncie advertised on Facebook Marketplace. One for £999 came on 3 days ago - no mention of whether a M20 or M21 - the other at £1400 appears to have come off a SBC powered car so may be a M20. Is yours an M21 like mine?. I think both are a little expensive. The Chodosh's may have an M21 I'll ask Bernie tomorrow for you.
 
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Blondie69

CCCUK Member
Roscobbc said:
A better move perhaps to have the existing 'box rebuilt - its a lot of work to fit an unknown quantity gearbox......only to later find that its knackered!
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Yes I have a great guy helping me with this. Just need to find a donor now. I bit like finding a unicorn 🦄 😳 but worth it.
 
Roscobbc

Roscobbc

Moderator
When you say 'donor' I presume you mean another gearbox needing re-build. What has happened to your existing gearbox? - is the casing irreprably damaged?
 
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Blondie69

CCCUK Member
Roscobbc said:
When you say 'donor' I presume you mean another gearbox needing re-build. What has happened to your existing gearbox? - is the casing irreprably damaged?
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It needs a complete gearset change. It looks like the clutch hasn't been clearing properly and its been crunching through the gears and Taken off the synchro teeth. So I am looking at rebuilding the original gearbox if possible.
 
CaptainK

CaptainK

Moderator
+1 to rebuilding the original gearbox. Then you know its a known good quantity, with warranty, and should last you a long time with added benefit you are keeping the car's originality. Getting a second hand "unknown" gearbox is just risking issues later down the line.

That said, if my original 4 speed died in mine, I suspect I'd probably "exaggerate" it a bit more so that my Financial Planner (wife :ROFLMAO:) will allow me to allocate funds to get a 5 speed gearbox into the car :cool:
 
Roscobbc

Roscobbc

Moderator
Blondie69 said:
It needs a complete gearset change. It looks like the clutch hasn't been clearing properly and its been crunching through the gears and Taken off the synchro teeth. So I am looking at rebuilding the original gearbox if possible.
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Not so many people here in UK who are knowledgable with Muncie variants - who has diagnosed it needs a new gearset?
 
B

Blondie69

CCCUK Member
CaptainK said:
+1 to rebuilding the original gearbox. Then you know its a known good quantity, with warranty, and should last you a long time with added benefit you are keeping the car's originality. Getting a second hand "unknown" gearbox is just risking issues later down the line.

That said, if my original 4 speed died in mine, I suspect I'd probably "exaggerate" it a bit more so that my Financial Planner (wife :ROFLMAO:) will allow me to allocate funds to get a 5 speed gearbox into the car :cool:
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😆.
Roscobbc said:
Not so many people here in UK who are knowledgable with Muncie variants - who has diagnosed it needs a new gearset?
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Clive Lansdale in Norfolk. Have you heard of him?
 
Forrest Gump

Forrest Gump

CCCUK regional rep
Blondie69 said:
It needs a complete gearset change. It looks like the clutch hasn't been clearing properly and its been crunching through the gears and Taken off the synchro teeth. So I am looking at rebuilding the original gearbox if possible.
Click to expand...
If the clutch is dragging you would be finding it very difficult to engage reverse gear.
What are the gearbox symptoms? ie which gears are difficult to select?
Hopefully you won’t need a complete gear set change. A rebuilt kit will come with a full set of syncro rings, bearings and gaskets. Then only replace individual gears if the engagement teeth are damaged (1st and 2nd take the most bashing). Be sure to get “torque lock” sliders as opposed to standard type….they're less likely to jump out of gear.
 
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