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9/14/16 11:46am - Original Message: 'Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
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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9/14/16 12:06pm - Reply: 'Re: Muncie M21 parts'
johnu
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Eagan, MN - USA

Vette(s):
1981 Corvette Two-Tone Claret color, 4 spd, C7 Vert

Joined: 5/23/2007
Posts: 504
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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9/14/16 12:43pm - Reply: 'Re: Muncie M21 parts'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#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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9/14/16 5:01pm - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
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
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9/16/16 10:37am - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
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
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9/16/16 2:08pm - Reply: 'Re: Muncie M21 parts'
BeachVette
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Ponte Vedra, FL - USA

Vette(s):
1972 Corvette Stingray Convertible

Joined: 4/12/2015
Posts: 1
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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9/16/16 5:29pm - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
Hi Bob, thanks for the recommend I'll have a look at their site.
Regards
Graham
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9/16/16 10:26pm - Reply: 'Re: Muncie M21 parts'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#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
Posts: 19448
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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9/16/16 10:53pm - Reply: 'Re: Muncie M21 parts'
gtr1999
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Wallingford, CT - USA

Vette(s):
1969 350 4 spd drop top 1972 350 auto coupe

Joined: 5/2/2016
Posts: 53
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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9/17/16 5:21am - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
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
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9/24/16 11:22am - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
I've been reading up on the subject and now have a better appreciation of what I am going to be up against but as a marine engineer of many years experience nothing to phaze me.
I bought a copy of Paul Cangialosi's excellent book which has been very informative.
As I will be going from a 4.55 to a 3.55 diff at the same time I'm going for a slight change of ratios in the box so the input shaft and countershaft gears will be new anyway, I now have a better idea of what is worn out unlike when I did my first gearbox as a youngster!!
I'll keep in touch as I progress.
Graham

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9/24/16 11:55am - Reply: 'Re: Muncie M21 parts'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#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:  I'm going for a slight change of ratios in the box so the input shaft and countershaft gears will be new anyway,


You're going for the overdrive conversion, aren't you?! Thumbs Up
Done a few for others....it's a good compromise to going to a 5 speed...and still looks original. Clap



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Joel Adams
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9/24/16 2:14pm - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
Hi Joel, not so much an overdrive but i'm changing my diff from a 4.55 to a 3.55 so thought my 2.2 1st gear would be a bit tall so I think I'll go with Autogears M22w set up which gives 2.56/1.75/1.36/1.00 ratios.
I've seen the o/d gears offered but a bit puzzled as to how it's achieved as top is normally straight through 1:1?
I had considered going for a 5 speed but with shipping and customs it's just a bit too much.
Graham
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9/26/16 1:24pm - Reply: 'Re: Muncie M21 parts'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#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
Posts: 19448
Graham, the O/D set-up for the Muncies is a neat deal. It actually changes 3rd gear to an overdrive ratio, leaving 4th gear as is. You flip the lever on the side cover for the 3-4 shaft over, and it now goes from 1st, to 2nd normally, and when you shift into what was 3rd, it actually shifts the trans to 4th(direct), then the shift into what was 4th is now an overdrive ratio replacing 3rd. The kit changes the cluster gear, along with the 2nd and 3rd(O/D) gears on the mainshaft. The 2nd gear change is so there isn't such a large gap between the 2nd and 4th(now technically) 3rd gear ratios.  Big smile

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Joel Adams
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9/26/16 2:21pm - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
I did wonder if that's how it's done a bit like a 3 speed and overdrive then. Graham
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10/6/16 8:43am - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
Took the box out last night and not a pretty sight, only half a key left in the 3/4 synchro hub so no wonder it had a bit of a crunch! the 1/2 hub is very loose and sloppy and the engagement teeth are a bit rounded so even if I wasn't changing the ratios they'd need replacement anyway, will hopefully get it all in bits tonight and see what the reverse gear is like then should be ready to order the parts, side cover looks good just needs new seals, I haven't measured the forks yet but they don't look too bad, although I already have a new set.
Will keep updating as I progress.
 
Graham
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10/10/16 10:40am - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
I was looking at my shifter yesterday and with a bit of fettling I think it should be salvageable, I think there should be a bias spring to push the lever over towards the 3/4 gate? which is missing had a look at the assembly manual and couldn't find a drawing there, am I right?
Graham 
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10/22/16 5:54pm - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

Vette(s):
1970 convertible in red 350

Joined: 10/6/2015
Posts: 82
Got my new clutch so that will go on first, when I removed the old one I found a needle roller spigot bearing, should I keep this or change it for the bronze bush supplied in the clutch kit?
Should get my gearbox parts in about a weeks time so will probably pulll my diff while I'm waiting.
Graham
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10/31/16 10:11am - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

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1970 convertible in red 350

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As the needle roller spigot bearing was in good condition I left it in place only cleaned it and gave it a lick of fresh grease, so new clutch mounted, gave the aluminium housing a good clean and a fresh coat of orange engine paint while it was off, new rubber boot fitted around the clutch arm as the old one fell to bits so will put that back on next then should be getting my gearbox parts through in the next couple of days so can get on with putting it all back together.
Decided to leave the diff until the gearbox is back in as didn't want to risk the jack coming from under the engine if I was struggling with the cross member etc!
 
Graham
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11/7/16 6:45am - Reply: 'Re: Muncie M21 parts'
Grahamred70
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, - United Kingdom

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1970 convertible in red 350

Joined: 10/6/2015
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Started building up the gearbox yesterday, all gears back in the box, just got to helicoil one of the mounting bolt holes on the tail housing before I put that back on and it's all ready to go back in.
The new speedo drive gear is a steel replacement for the original plastic one, does anyone have any measurements to make sure I get it in the right position?
 
Graham
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