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Muncie M21 parts (1/33)
 9/14/16 11:46am
Grahamred70
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, - United Kingdom

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1970 convertible in red 350


Joined: 10/6/2015
Posts: 83

Hi Guys and gals,
my Muncie has been misbehaving recently and last weekend I thought I'd do an oil change to see if it improved matters but when I took out the drain plug I heard something land in my drainer and when I looked there were 2 broken synchro keys lying there!
I put them together but they didn't match so at least 2 are broken, on a recent run involving a lot of hills it started to drop out of 2nd on the over run and I need to double declutch up and down into 3rd to avoid a crunch so guessing that's where the keys are from, the other recent fault is that sometimes although it feels like it's in first it's not quite and needs an extra push.
Runs quiet so guessing there's no gear issues or bearing problems, 1st and 2nd problems I guess could be the selector fork? and keys from 3/4 synchro.
Any suggestions for a parts supplier?
 
Graham
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Re: Muncie M21 parts (2/33)
 9/14/16 12:06pm
johnu
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Scottsdale, AZ - USA

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1981 Corvette Two-Tone Claret color, 4 spd, C7 Vert


Joined: 5/23/2007
Posts: 552

I had a similar problem years ago.  The forks were worn to where they would not push the syncro's far enough.  Two new forks and it worked fine.


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Re: Muncie M21 parts (3/33)
 9/14/16 12:43pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


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The broken keys are more likely from the 1-2 synchro assembly, since you have to sometimes man-handle it into 1st, and it falls out of 2nd on deceleration. The grind on the 3-2 shift is most likely just normal wear/tear on the brass rings. There is probably some wear on both forks, for sure.....there almost always is. Regardless, the trans will need to be removed and repaired. While it's out, might as well go ahead and do a complete rebuild, with new bearings/brass/seals, plus whatever worn/damaged parts that need replacing.
I wouldn't recommend doing much more driving with known broken synchro keys....you could do a lot of damage if even a small piece of one gets in between two gearsets....ouch! Those keys also help keep the brass(synchro rings) from spinning on the hubs/gears. If the brass starts spinning like that, it can damage the hubs....more $$$$, not to mention the grinds while shifting will wear the synchro teeth off of the speed gears rather quickly. Ouch

|UPDATED|9/14/2016 9:43:26 AM (AZT)|/UPDATED|


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Joel Adams
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Re: Muncie M21 parts (4/33)
 9/14/16 5:01pm
Grahamred70
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, - United Kingdom

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1970 convertible in red 350


Joined: 10/6/2015
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Hi Joel, I don't quite have to manhandle it into 1st just a little extra pressure and it goes in, I suspect this is more likely to be selector fork worn which would also explain the jumping out of 2nd, something I experienced many years ago on a Ford, it was only when i got the new forks I realised how badly worn they were( I thought they were machined that way!)
It's 2-3 or 4-3 where I get the crunch which leads me to suspect that's where the broken keys came from, obviously when it's out I'll do a full overhaul replacing any worn or broken parts, new bearings and seals, etc.not a job I'm particularly looking forward to but certainly not a job i want to do more than onceWink
More importantly I'm looking for a source of good quality parts at fair prices, any suggestions anyone?

Thanks
Graham
Re: Muncie M21 parts (5/33)
 9/16/16 10:37am
Grahamred70
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, - United Kingdom

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1970 convertible in red 350


Joined: 10/6/2015
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Does nobody do their own repairs any more? unfortunately I don't have the luxury of exchange reconditioned units in the UK so I have to do it myself, I've done gearboxes myself in the past so not phased at all but would like some help as to where to obtain good quality parts as once it goes back in the car I don't want to be pulling it out again a few months down the road.
So far I've looked at autogear and American powertrain warehouse as well as a couple of others, many of which seem to offer the same items.
Obviously I wont know exactly what I need until I get into it and don't want to order a load of parts and find all that's needed are the keys and springs but would really appreciate some advice.
 
Thanks
Graham
Re: Muncie M21 parts (6/33)
 9/16/16 2:08pm
BeachVette
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Ponte Vedra, FL - USA

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1972 Corvette Stingray Convertible


Joined: 4/12/2015
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I bought my rebuild kit for my Muncie 20 from Paul Cangialosi at Medatronics Corp in Tequesta, Fl.  Phone # (561) 743-5600.  I rebuild the Muncie myself - my first attempt and it isn't that difficult.  I bought Paul's book on Muncie 4-speeds - How to rebuild and modify and just followed his very detailed instructions.  His web site is www.5speeds.com  He also rebuilds Muncie's.
 
Bob


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Re: Muncie M21 parts (7/33)
 9/16/16 5:29pm
Grahamred70
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1970 convertible in red 350


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Hi Bob, thanks for the recommend I'll have a look at their site.
Regards
Graham
Re: Muncie M21 parts (8/33)
 9/16/16 10:26pm
Adams' AppleLifetime Member
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Duncanville, TX - USA

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#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas


Joined: 11/8/2003
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Grahamred70 said: Does nobody do their own repairs any more?
 
Thanks
Graham


LOL
I do mine, Graham. I also build transmissions for a living. I haven't given any suggestions on where to get parts because of your location. I've shipped trans parts over to that side of the pond for another C3VR member....and it turned into a big "hurry up and wait" situation with customs.
The best place(imho) in the states to get whatever you need for it is Kajun Jon's . Don't know if he ships overseas or not, but you can certainly contact him once you find out what all you need.  Thumbs Up


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Joel Adams
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Re: Muncie M21 parts (9/33)
 9/16/16 10:53pm
gtr1999
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CHESHIRE, CT - USA

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1969 350 4 spd drop top 1972 350 auto coupe


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BeachVette said: I bought my rebuild kit for my Muncie 20 from Paul Cangialosi at Medatronics Corp in Tequesta, Fl.  Phone # (561) 743-5600.  I rebuild the Muncie myself - my first attempt and it isn't that difficult.  I bought Paul's book on Muncie 4-speeds - How to rebuild and modify and just followed his very detailed instructions.  His web site is www.5speeds.com  He also rebuilds Muncie's.
 
Bob



That would be my recommendation as well, if you go to web site or you tube you will find some good videos. Muncie's aren't too bad to work on but the gears are made outside of the USA now.

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Re: Muncie M21 parts (10/33)
 9/17/16 5:21am
Grahamred70
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, - United Kingdom

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1970 convertible in red 350


Joined: 10/6/2015
Posts: 83

Thanks guys, that's the kind of info i nee, I understand the problems of getting parts delivered and the often high additional costs of shipping and duty.
I've managed to make contact with the Italian manufacturer, Antonio Masiero, that a lot of the US parts suppliers are using and come highly recommended with users and am hoping they can supply via a European agent if not direct, they initially pointed me to Autogear in the US as their exclusive agents.
Thanks
Graham