Pretty Muncie

[allcoupedup]

THought I'd share these pics. My Muncie is almost done. All gears are new except the reverse gears. New sliders and forks too. New tailhousing, bearing retainer, reverse shift shaft, new synchros, new bearings and small parts kit, new countershaft pin. If anyone want to rebuild their trans but is hesitant... DON't be! This was a great project. All you need is the video, some patience, basic tools, and some time. This is an early M20 with the 2.56:1 first gear and a 7/8" countershaft pin.

Brian

gears from left to right:
input (4th), 3rd, 2nd, 1st, reverse, speedo drive. Cluster gear and reverse idler gear assembly not pictured.

 

[Ron Miller]

Lookin' Good!!! Congrats!!!!

 

[Bill75]

Thanks for your comments on this, I was thinking about doing it some time and ordering the video. Murphy always seems to raise his ugly head around my garage so it was nice to hear you had good luck with it. I assume the video was done well enough that you were able to follow it OK. Had you ever done a trans. before?

Bill

 

[allcoupedup]

Bill,

The video is awesome. He (Paul) says several times that the purpose of the video is to rebuild a muncie with "conventional shop tools". My muncie had no speedo drive gear so I didn't need a press. Yours will probably have it so you will need a few minutes shop time (can see it taking them more than 5 minutes). I put the new speedo gear on by heating it with a propane torch (expands) and sliding it back on. The hardest part was cleaning everything. I used kerosene and a bucket.

This was my first transmission and I really never understood how they worked until it was completely apart. The video is basic enough to walk a first timer through it. He covers disassembly, checking for wear, and then assembly.

Go for it!
Brian

 

[67HEAVEN]

I so love seeing these do-it-yourself projects.

 

[Ken]

Now those are pictures we "gearheads" love to see, right?

 

[Tom Bryant]

Lookin' good.

 

[6T7Redvette]

Lookin' good.

That does look like a nice job!

What tools did you use? Can someone with absolutely no transmission experience do the job? It almost appears the hardest part is getting the tranny out of the car and reinstalling.

 

[allcoupedup]

Here's what I used: punches, screwdrivers, a ball-peen hammer, a flat file, some kerosene, ratchet set, a dremel tool, 400 grit sand paper, small propane torch (same one for sweating copper), pliers, and the video. Oh yeah... the tool I used most was my pocketbook.:L I did have to use a 90 degree screwdriver to get the reverse shift shaft detent ball in place but there are other ways I'm sure. I recommend the special wrench. I used a pipe wrench and it knicked up the gland nut, I filed it down and am concerned I got some filings in the front bearing. I'll get the wrench , a new nut, and clean the bearing. Don't forget penetrating oil.

You do need a press to get the speedo drive gear off. Any shop should be able to do this for a few bucks. I also bead blasted some stuff but it is not necessary.


Can someone with no transmission experience do it?? Absolutely! That was me a few months ago. I have not removed or installed a muncie in a corvette yet and hear it can be a real pain.


This is a great project because there are so many little parts you feel like real progress is being made.

Brian

 

[allcoupedup]

Almost forgot --- I did need to buy a snap ring pliers. Picked one up at Autozone but it was really constructed for very small rings with holes in the ends. I ended up using a piston ring spreader to get most of the snap rings off - that part was frustrating.


Brian

 

[ctjackster]

Brian - looks great. I must say you have urged me to do some other things that were spooking me (distributor rebuild comes to mind) but the "I really f-d up by tackling this one" factor is HUGE when it comes to a transmission, at least in my weenie world. You're gonna have to really sell me.

First, though - what was going on with your tranny that led you to believe a rebuild was in order? (Mine is actually fine, so I may dodge this assignment).

 

[allcoupedup]

Jack,
With the LT1 cam and the M21 in the car and the 3.36:1 rear end, the car is kinda sluggish on the bottom end. In fact, I have to slip the clutch a little to get her moving. SO.... I wanted some off the line improvement w/o sacrificing too much drivability and the M20 will do this. The 1st gear ratio on the M20 is 2.56:1 compared to 2.20:1 on the M21. SO.... my M20 with the 3.36:1 rear end will be roughly equivalent to an M21 with a 3.90:1 rear end BUT the 4th gear ratio is still 1:1 on both the M20 and the M21.

The M21 in the car is fine but I didn't want any downtime so I purchased an M20 off of EBAY for about $300 shipped. The price was too good to be true because it was all beat up. I also thought i heard something rattling around and it turned out to be a broken shift key. Had I used the transmission in that state it could have exploded everything.

I wouldn't rebuild a transmission unless it is leaking, grinding, or popping out of gear. In all honesty, the "uh oh" factor is not too bad here because it is hard to assemble it wrong.

SO ... now I have a new engine, new transmission, and now I need some frame and suspension work done. Would have been much smarter to do a body off but the parable of the boiled frog comes to mind here when considering the wife and the funds

Brian
Brian

 

[6T7Redvette]

Jack,
With the LT1 cam and the M21 in the car and the 3.36:1 rear end, the car is kinda sluggish on the bottom end. In fact, I have to slip the clutch a little to get her moving. SO.... I wanted some off the line improvement w/o sacrificing too much drivability and the M20 will do this. The 1st gear ratio on the M20 is 2.56:1 compared to 2.20:1 on the M21. SO.... my M20 with the 3.36:1 rear end will be roughly equivalent to an M21 with a 3.90:1 rear end BUT the 4th gear ratio is still 1:1 on both the M20 and the M21.

The M21 in the car is fine but I didn't want any downtime so I purchased an M20 off of EBAY for about $300 shipped. The price was too good to be true because it was all beat up. I also thought i heard something rattling around and it turned out to be a broken shift key. Had I used the transmission in that state it could have exploded everything.

I wouldn't rebuild a transmission unless it is leaking, grinding, or popping out of gear. In all honesty, the "uh oh" factor is not too bad here because it is hard to assemble it wrong.

SO ... now I have a new engine, new transmission, and now I need some frame and suspension work done. Would have been much smarter to do a body off but the parable of the boiled frog comes to mind here when considering the wife and the funds

Brian
Brian

Brian,
Thanks for the reply. The tools you used don't appear to be anything us shade tree mechanics wouldn't already have. How about working to tolerances. Any issues??? I'm thinking about doing my transmission over next winter. The synchro need replacing.

 

[allcoupedup]

Nothing really - I checked the cluster gear end play and it was in spec - end play was ~.010 and only needed to be under .035. For this measurement I used a digital caliper from Harbor freight (about $15) - no dial gauges or anything. The video didn't suggest anything except checking the countershaft end play so I didn't check anything else.

Brian

 

[6T7Redvette]

Nothing really - I checked the cluster gear end play and it was in spec - end play was ~.010 and only needed to be under .035. For this measurement I used a digital caliper from Harbor freight (about $15) - no dial gauges or anything. The video didn't suggest anything except checking the countershaft end play so I didn't check anything else.

Brian

Brian,
Thanks for the help. Be sure to keep us posted. I'd like to hear how you did removing the old tranny and reinstalling the new one. Good Luck

 

[ctjackster]

Jack,
With the LT1 cam and the M21 in the car and the 3.36:1 rear end, the car is kinda sluggish on the bottom end. In fact, I have to slip the clutch a little to get her moving. SO.... I wanted some off the line improvement w/o sacrificing too much drivability and the M20 will do this. The 1st gear ratio on the M20 is 2.56:1 compared to 2.20:1 on the M21. SO.... my M20 with the 3.36:1 rear end will be roughly equivalent to an M21 with a 3.90:1 rear end BUT the 4th gear ratio is still 1:1 on both the M20 and the M21.

The M21 in the car is fine but I didn't want any downtime so I purchased an M20 off of EBAY for about $300 shipped. The price was too good to be true because it was all beat up. I also thought i heard something rattling around and it turned out to be a broken shift key. Had I used the transmission in that state it could have exploded everything.

I wouldn't rebuild a transmission unless it is leaking, grinding, or popping out of gear. In all honesty, the "uh oh" factor is not too bad here because it is hard to assemble it wrong.

SO ... now I have a new engine, new transmission, and now I need some frame and suspension work done. Would have been much smarter to do a body off but the parable of the boiled frog comes to mind here when considering the wife and the funds

Brian
Brian

I guess none of us L76 owners told you about the issues that engine presents coming off the line - you almost need to stage and rev it like you are at the Winter Nationals and the tree is going green - at least I have a 4.11 - this combo makes the best sense (your solution is elegant too), at least until you take a long highway trip with the 4.11 rear, 'specially with the sidepipes. I still call it music though . . . and I bought the car for blasts down twisty backroads anyway, and admiring stares from young women that I stand absolutely no chance with . . . .

 

[67HEAVEN]

The 1st gear ratio on the M20 is 2.56:1 compared to 2.20:1 on the M21. SO.... my M20 with the 3.36:1 rear end will be roughly equivalent to an M21 with a 3.90:1 rear end BUT the 4th gear ratio is still 1:1 on both the M20 and the M21.

Is this a good time to whip out my spreadsheet again?

These calculations helped me decide on a 3.08:1 rear (dropped the 4.56:1) to go with a new Richmond 5-speed. Now, 1st is still like having a 4.56:1 rear when I ran the old M-21, while 5th is now straight through to 3.08:1.

It'll go a lot faster than I want to anymore. Ohhhhhhhhhhhhhh baby!!!

 

[Viet Nam Vett]

You Know....The ladies must think we are crazy... We look at the inside of a Muncie or a Big Block or a rear Diff and we get wet shorts... They probably don't get it.

Truely ..Men are from Mars and the Chickies are from Veinus....or is that the other way around???

Nice looking Muncie...!!!!

 

[maxphunn]

Hey Brian, it looks good. It isn't uncommon for someone to mix up the 1st/2nd and 3rd/4th sliders, they look almost the same. The only part of a Muncie rebuild that gives me grief is that dang little detent ball. Does the video give a trick for that?

 

[allcoupedup]

maxphun,

New sliders both have the edge cut so there is no difference. In the video he highlights the differences between the original sliders and shows how set them up correctly.

That little detent ball was indeed a pain in the behind. Paul uses a bent screwdriver in the video but I wasn't about to bend up one of mine for a one time thing. I then remembered a had a 90 degree screwdriver ( an "L" shaped screwdriver) from a craftsman set that I never used and it took 20 seconds. If I would have had an old screwdriver around I would have bent the tip 45 degrees.

Brian