Muncie ID

[William O.]

I am trying to ID what I think is an early 1967 Muncie transmission here is the following info:

Right side casting number: Casting: 3885010

Left side Assembly date: P0922
Vin Number: S102880

After reading the TIM and other doc's I think this was assembled Sept 22, 66?


Thank you.


Bill

[Sam K.]

Re: Muncie ID

Bill: The Cast # on the Main Case is Correct... Do you have the correct Tailhousing Cast, Side Cover Cast & Frt Brg Retainer Casting, alon g with an ID Tag???
they should be as follows: Tail #3857584, Side #3884685, Frt Brg#3851326. In addition, is this an M20, M21 or M22? Does the input shaft have ID Rings, and 10 splines, with the output spline being 27?
The internal gear count can determine which Muncie you have...

[Wayne M.]

Re: Muncie ID

I am trying to ID what I think is an early 1967 Muncie transmission here is the following info:
Right side casting number: Casting: 3885010
Left side Assembly date: P0922
Vin Number: S102880

After reading the TIM and other doc's I think this was assembled Sept 22, 66? Bill

Bill -- it was assembled in Muncie IN on 22nd September 1965. It was installed in '66 Corvette with VIN derivative S102880 (sometime in early to mid-October ?) Normally, we'd expect to see a '6' before the S102880, as just the 'S' is a (sort of a blended) carry-over from the 1965 Corvette stamping format.

EDIT: or more precisely the '63-4 format was S1xxxx; the '65 was 51xxxx; the '66 was 6S1xxxxx and the '67 same but with 7S1....

If it was on a '67 Corvette, it would be P7P22 date stamped, for 22nd Sept 1966 (1967 model year).

[William O.]

Re: Muncie ID

Sam:

M22?

The tail housing is 3857584 Side 3884685 Frt. Brg. 3915020

No ring, None Spline: 10 Output 27.

Thanks.

Bill

[William O.]

Re: Muncie ID

Thanks you.

Bill

[William C.]

Re: Muncie ID

The lack of a "ring" on the input shaft indicates a replacement input shaft and gear, originals carried one ring (close ratio) or 2 rings for wide ratio configuration.

[Wayne M.]

Re: Muncie ID

Or, further to the M22 subject, and to confirm Bill C's remarks, if this trans is on the bench, just remove the side cover to inspect gear(s) angle.

Also, if on bench, just put it in 1st gear and turn the output or input shafts a sufficient number of turns to determine the 2.20 ratio for close gear set OR for (possibly, per above) M22. [don't get your hopes up ].

[William O.]

Re: Muncie ID

I will take some pictures, and post

Thanks,

Bill

[William O.]

Re: Muncie ID

Picture 008m.jpg

Attached is the picture.

Thank you for your help!

Bill

[William C.]

Re: Muncie ID

M-20 or M-21 based on the gears, tooth count on the input or shifting it into low and checking the input rotations to achieve 1 output revolution is is the only real way to verify M-20 or M-21 in this case.

[Wayne M.]

Re: Muncie ID

[ATTACH]14695[/ATTACH]

Attached is the picture.

Thank you for your help!

Bill

BINGO, Bill, you've got yourself an M22 . But there's one thing I notice that may indicate that some or all components have been changed. We've already determined by the stampings that the case was originally assembled in Sept 1965. Looking at your pic, I see the 3-4 slider with the thick shoulder, which I believe started only in 1968 [I'd have to check my books].

Compare with gears on this shot of one of mine, from an original April 1969 trans .

[William C.]

Re: Muncie ID

Wayne, if you blow both pictures up to the same size, the helix angle on the gears is definitely M-20 or M-21 style, not at all a match for your M-22.

[John H.]

Re: Muncie ID

Looks like an M-22 to me - photos below of M-20/21 and M-22 gear helix angles (M20/21 on the left, M22 on the right).

[Wayne M.]

Re: Muncie ID

Wayne, if you blow both pictures up to the same size, the helix angle on the gears is definitely M-20 or M-21 style, not at all a match for your M-22.

Bill -- here's a pic of two 3rd gears; M20/21 on the left; M22 on the right. To differentiate (where there's no comparison available), I draw an imaginary line through the mainshaft axis and from one edge of a tooth, and see how it intersects with the next tooth; if it hits the middle (like the left example), it's M20 or M21. If it just intersects the far edge of the adjoining tooth, or just misses (not all forward gears are the same width), then it's M22.

The photography can fool as well. Best is shot in zoom mode from a distance, to reduce the "barrel" effect of close-up lenses. A tricky eBay seller could use this to advatage to create uncertainty, especially as 80% of sellers believe that theirs could be an M22 .

When I look at Bill O's pic, I see M22 tooth angles.

P.S. I want to correct what I said about VIN derivative stampings on the maincases, yesterday [since my edit timeframe has expired].

'63 and '64 were Y1xxxxx (where Y=year); '65 was S1xxxxx [except first ~2000 cars; mixed earlier format or with S overstamp on the 5]; '66 and '67: YS1xxxxx.

[William C.]

Re: Muncie ID

Looks like you may be right. I certainly hope so for his sake, that's like an order of magnitude difference in the value of the box!