Kid_Again
Well-known member
- Joined
- Jul 6, 2004
- Messages
- 1,171
- Location
- NJ - Which exit you from?
- Corvette
- 65 SB Roadster, 66 BB Coupe
This ought to be interesting.
I'm replacing my #match M20 Muncie in the '66 with a '69 M21 that I bought for $200 a few years ago. I thought it would be a good time for me to learn how to rebuild a Muncie and I got some tips from Gary (GTR1999) to get me started. Since I couldn't wait for the instructional video to arrive in the mail (and I seem to be incapable of following the shop manual), I just HAD to crack the case and see what was inside. Actually, all the gears looked pretty good with the exception of the reverse pinion gear which has some ground up teeth. No chips in the case and it looks like the previous owner used Redline oil so it seems to have been well cared for. The obvious problem is that all the bearings sound like potato chips. I THINK they are the original bearings. The speedo gears need replacement.
If you see the cracked case picture, you'll see the first problem. The idler shaft has a flat ground into it and that flat should be on the bottom...you can see that it is not aligned correctly so that, I think, means it was rebuilt by a hambone.
The casting and applied numbers say it is a September '69 M21 and it has a single ring on the input shaft.
Of course, I messed up because I should have unscrewed the nut on the input shaft and it'll be a booger to get it off now. A "Muncie Nut Wrench" costs $50 and to hell with that. All I need is to cut some 3/8" flat stock in the shape of a wrench and cut a "U" slot to grab the nut. It's left hand thread, I believe.
I'll post pictures as I move along at a snail's pace. It was either Mac or Tom Bryant who put money down that I'd wind up with 4 reverse speeds and one forward. Cute, real cute. Hey, at least I don't have an annoying split window to block my view.
BTW, see that heart stamped into the boss on the top of the case? WTF is that? Maybe the mark of the previous hambone?
ttfn
I'm replacing my #match M20 Muncie in the '66 with a '69 M21 that I bought for $200 a few years ago. I thought it would be a good time for me to learn how to rebuild a Muncie and I got some tips from Gary (GTR1999) to get me started. Since I couldn't wait for the instructional video to arrive in the mail (and I seem to be incapable of following the shop manual), I just HAD to crack the case and see what was inside. Actually, all the gears looked pretty good with the exception of the reverse pinion gear which has some ground up teeth. No chips in the case and it looks like the previous owner used Redline oil so it seems to have been well cared for. The obvious problem is that all the bearings sound like potato chips. I THINK they are the original bearings. The speedo gears need replacement.
If you see the cracked case picture, you'll see the first problem. The idler shaft has a flat ground into it and that flat should be on the bottom...you can see that it is not aligned correctly so that, I think, means it was rebuilt by a hambone.
The casting and applied numbers say it is a September '69 M21 and it has a single ring on the input shaft.
Of course, I messed up because I should have unscrewed the nut on the input shaft and it'll be a booger to get it off now. A "Muncie Nut Wrench" costs $50 and to hell with that. All I need is to cut some 3/8" flat stock in the shape of a wrench and cut a "U" slot to grab the nut. It's left hand thread, I believe.
I'll post pictures as I move along at a snail's pace. It was either Mac or Tom Bryant who put money down that I'd wind up with 4 reverse speeds and one forward. Cute, real cute. Hey, at least I don't have an annoying split window to block my view.
BTW, see that heart stamped into the boss on the top of the case? WTF is that? Maybe the mark of the previous hambone?
ttfn