Muncie Transmission Tag

[Lane Ockerman]

I have a 65' 327 / 365 with a Muncie CR Trans. The I.D. tag is #3857573
A friend of mine has a 65' 327 / 350 with a Muncie CR Trans. with I. D. tag #3857579.

Are these I.D. Tags correct for these Muncie transmissions??
Were they interchangsable or was the I.D. # specific to each transmission??

Thank You for any assistance.

Lane

[Michael H.]

Re: Muncie Transmission Tag

Lane,

I don't happen to have a 65 AIM handy to check the part numbers but I would guess that the reason for the difference may be the fact that these cars have different differential ratios, which would have required a different speedo drive gear. This would call for a different part number transmission.

[Wayne M.]

Drive Gear-related, not plastic driven ...

... gear, as Michael says. Example: pulled the 4-speed in my '65 L79 with factory 4.11's in the fall of 1976 (no previous visits by NCRS or BG types ) and found tag 3857579. Same tag found in early '80's on my '65 L76, which also has its original 4.11's.

From AIM, check M20 and G81 sheets. Not really clear except that a 4.56 rear requires a 3857582 tag. There should be 3 tags in all, for the 3 drive gears; don't know why there's more, or why there may be different tags for some L78's (they used the same trans, IMO).

Michael: did the final chassis assy line insert the proper colored plastic gear per the build order ?

[Mike M.]

Re: Drive Gear-related, not plastic driven ...

Hi Guys, Great Timing.
I can't find any stampings on my '65's punkin.
Any idea what the tag 3857577 on my M-21 represents?
Thanks,
H. a. N. D.

[Jack H.]

Re: Drive Gear-related, not plastic driven ...

If you've got a 4-spd car, turn to the options section of your AIM book (M20/22) and you'll see the various assembled tranny PN's called out. Unfortunately, the closest I see to the 3857577 number you reference is 3857573 (M20 with L76 & L84) or 385759 (M20 with L79)...

[Wayne M.]

'65 Trans Tags -- Addendum & Correction

Should be theoretically 4 trans tags, (not 3 as I said earlier); due to need for 2 different transmissions (2.20 close ratio and 2.56 wide ratio) both with a speedo drive gear for the 3.08 thru 3.55 group of driven plastic gears only. In the 1965 model year all close ratio boxes would have used 3857573 tag for the 3.08-3.55 final drive sets.

Just been through my stack of P & A 30's and here's all I can come up with.

To Michael Murray: 3857577 shows up as a wide ratio trans tag (available only with 3.08-3.55 diff ratios). This was replaced by 3880857 for SERVICE in 5-66, which was the "010" maincase equivalent.

The 3857582 tag number (4.56 speedo drive, close ratio boxes only) was removed from SERVICE 1-65, then replaced by 3880857 on 5-66.

This leaves the 3857579 to service the close ratio boxes with 3.70 to 4.11 final drives.

But there must be more to this story, as there are other numbers out there; 3857580, 81 (ignoring the M22's)

Could someone with a clear copy of their '65 AIM tell me what the Revision record says ?

[Lane Ockerman]

Re: Muncie Transmission Tag

Thank You All for response!!

[Jack H.]

My AIM's revision record...

is blank with one notation "Redrawn & Revised" effective 4/23/65 with respect to UPS M20/M22, Sheet 1. Looks like we'd either have to find a different AIM source (mine has 'Graphic Drafting' source headers) or look back in time to a '64 AIM copy...

[Wayne M.]

How about UPC G81 ? can't make mine out

... Sheet 1; but then I'm also working from a Graphic Drafting version with T.Michaelis covers (circa 1975).

[Jack H.]

Re: How about UPC G81 ? can't make mine out

Sorry, mine's in about the same condition as your book with respect to being able to read the G81 Revision Record. Why not pop open Noland Adams on this one? If memory serves he gives a pretty good set of tables by ECL code as to what was what in terms of running change info...

[Jack H.]

PS...

If you do go to Noland's G81 tables, look around and note the data 'proves' a limited number of M22 (Rock Crusher) equipped Corvettes were built and shipped in 1965!

[Ray C.]

Re: PS...

I have a July, 1963 340HP with 3:55 gears. The 63 still has its original Muncie transmission with matching numbers and the side cover tag number is: 3831815.

Ray

[Dick G.]

Re: Muncie Transmission Tag

My Jan. 65 car with 350HP original rusty tranny tag reads 3857581. DG

[Mike E.]

Re: Muncie Transmission Tag

I've been looking at these tags for a number of years. 62 T-10's had smaller tags with only a single letter or a double letter. Muncies then went to the longer tag with the GM 7-digit part number on it. I've found, at least in the 68-72 era, that if the tag remains, you can cross-reference with the AIM and determine whether or not you have an M-20, 21, or 22, simply by looking at the tranny part number call-out. On Saturday I was under a 27k mile 72 LT-1 and the tag corresponded to an M-21. HOWEVER--what I'd love to figure out is that on some of these there is a two-letter code following the 7-digit part number. this 72, for example, has a WK. Any idea what that means? Unfortunately, I couldn't read the stamping on the rear end on that car, to see the ratio and try to correspond that with a drive gear. Can anybody help there?

[Mike M.]

Thanks, Wayne! *NM*