Author Topic: Muncie trans question  (Read 1722 times)

althomas55

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Muncie trans question
« on: August 07, 2018, 01:01:53 AM »
 Speedometer stopped working ,( M-21) thought cable crapped out  pulled the speedo cable checked it out and not broken ! :( removed speedo bullet put finger in tail shaft and felt gear inside to be way forward of where bullet gear could engage it ,and can slide it back and forth quite far .Once or twice prior to speedo quitting I thought I heard a strange zingging ,whining type noise and slight vibration in the shifter handle but dismissed it as the radio, ( except for shifter vibration yesterday,vibration lasted couple seconds then quit ) as all seemed well with gear shifting and driving , no shaking,clunking,crashing or any other abnormalities ! In my 63 years never had a trans. apart and was curious as to why this gear could slide forward ( towards engine ) so far ? Do I possibly have a big problem brewing, does the tail shaft slide off easily as a turbo 350 does , or do I need to bite the bullet and yank the tranny  :-[ ? Thanks in advance for any insight !
68 RS clone 468/4spd

bcmiller

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Re: Muncie trans question
« Reply #1 on: August 07, 2018, 01:12:28 AM »
What year is the transmission? On the later ones - after 67 I think? canít remember for sure - there is a clip to secure the speedo drive gear.  The ones with a clip are the plastic or nylon type drive gear. I would have to look that up.

Itís almost always easier - at least for me - to pull the trans and work on it while on the bench.
« Last Edit: August 07, 2018, 08:43:04 AM by bcmiller »
Bryon / 1968 Camaro SS 396 coupe - now old school 468 big block
1967 Camaro RS/SS 396 coupe L35/M40 - 4 generation family project
Looking for 68 Camaro with body # NOR 181016

althomas55

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Re: Muncie trans question
« Reply #2 on: August 07, 2018, 01:28:24 AM »
 Car is 68 but not sure of the trans year as car was in pcs. when I got it, car is not original , started life as a 6 cyl. now a 468 resides under the hood, 342 corporate gm 10 bolt rear with the 4 speed doesn't seem to lack for power , fun to drive , not so much fun to work on anymore ! ;D
68 RS clone 468/4spd

67jeffreyt

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Re: Muncie trans question
« Reply #3 on: August 07, 2018, 01:54:13 AM »
In my Muncie group I believe it's just a press fit and the tail shaft gear can move, I will share your post in the group, the founder of the group is a professional Muncie rebuilder as his regular job.
67 ss/rs camaro currently
68 prostreet Camaro 9.60 1/4 mile
68 Rallysport, first car high school
89 rs camaro convertible, made readers rides super Chevy

Tx-Z 302

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Re: Muncie trans question
« Reply #4 on: August 07, 2018, 02:52:58 AM »
In my Muncie group I believe it's just a press fit and the tail shaft gear can move, I will share your post in the group, the founder of the group is a professional Muncie rebuilder as his regular job.
id sure like to join a muncie group?
Chris W

z28z11

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Re: Muncie trans question
« Reply #5 on: August 07, 2018, 03:42:34 AM »
My '69 M20 broke the clip under the shaft gear, and proceeded to jam the reverse selector with the remains of the clip. Goofy design to be sure - the spring clip fatigues over time, and becomes a problem. You'll have to pull the tailshaft housing to correct it. There are several options to replace if the gearset and clip are like my '69's problem including ones like this :

https://www.ebay.com/itm/MATCHING-SET-ALUMINUM-MUNCIE-POWERGLIDE-SPEEDOMETER-SPEEDO-GEAR-COMBINATION-KIT/192617012588?hash=item2cd8de5d6c%3Ag%3AWw8AAOSwal5YG1BZ%3Asc%3AUSPSPriority%2137087%21US%21-1&_sacat=6028&_nkw=Muncie+speedo+clip&_from=R40&rt=nc&_trksid=m570.l1313

Not terribly difficult, but a pain in any case. My gear was metal, not plastic, and I reused it. Clip was sourced from GM, and yes, you'll really need to pull the trans as it will need some wiggling to clear the tailhousing from the reverse gear selector. Do yourself a favor and don't try to drive the staking pin out of the reverse shifter boss on the tailshaft - the (tapered) pins are usually frozen in place by this age, and you'll bend them or mangle the tailshaft housing if you try to pound them out. With a little creative wiggling, you can disengage the selector from the slider and pull the tailshaft housing clear. Actually a fairly quick process, discounting the fact you have to pull the trans.

Regards,
Steve
1968 Z28 M21/U17 BRG/W 1967 Chevy ll Nova SS 
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06  1949 3100 5wd 235/6

67jeffreyt

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Re: Muncie trans question
« Reply #6 on: August 07, 2018, 11:10:29 AM »
Craig's response, and the Muncie group is on Facebook, anyone can join, Craig Wright is the founder of the group.  It is Muncie 4 speed & GM manual transmissions buy sell trade, but it's a tech forum group.
67 ss/rs camaro currently
68 prostreet Camaro 9.60 1/4 mile
68 Rallysport, first car high school
89 rs camaro convertible, made readers rides super Chevy

67jeffreyt

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Re: Muncie trans question
« Reply #7 on: August 07, 2018, 11:12:24 AM »
A lot of responses on this forum are very informative too, sounds like a lot of great advice here also
67 ss/rs camaro currently
68 prostreet Camaro 9.60 1/4 mile
68 Rallysport, first car high school
89 rs camaro convertible, made readers rides super Chevy

althomas55

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Re: Muncie trans question
« Reply #8 on: August 08, 2018, 01:45:55 AM »
Thanks for all the responses, looks like I'll be pulling the trans. not what I wanted to do but was fairly sure that would be the case , not as concerned about the speedo issue as I am about the vibration felt in the shifter handle a couple times makes me envision something jamming up and destroying the tranny while I'm going down the road 60 mph !
68 RS clone 468/4spd