1974 Muncie side cover question

[Rich Puleo]

Hey all,
I've got my 74 apart finally. Basically an original low mileage car, but I'm trying to decipher the transmission. I took the original wide ratio Muncie out of the car. I cleaned some of the grease away to view the numbers & found the original stampings in tact, correct case & tail, but the side cover has a weird cast of 2 335308, thin characters. The 2 is much bigger than the others. So here we go, it's been off the road many years, at least 20, with about 65k on it, & it doesn't look like it was ever apart. So has anyone seen this & what gives? Replacement cover?
Thanks,
Rich

[Chuck S.]

Re: 1974 Muncie side cover question

If your Muncie four speed is like earlier versions, you should have found a metal tag on one of the side cover bolts. That metal tag has the part number of the transmission. If it's missing, the side cover was probably removed from the transmission or replaced at one time. If the tag is there, that doesn't mean that the cover has never been removed...only that, if it was removed, the wrench man was a craftsman.

I can't tell you anything about the casting number, but I wouldn't worry until Joe Lucia or someone else says it's a replacement. The larger numerals like the2 are common...it is very likely NOT part of the casting number.

[Chuck S.]

Re: 1974 Muncie side cover question

If your Muncie four speed is like earlier versions, you should have found a metal tag on one of the side cover bolts. That metal tag has the part number of the transmission. If it's missing, the side cover was probably removed from the transmission or replaced at one time. If the tag is there, that doesn't mean that the cover has never been removed...only that, if it was removed, the wrench man was a craftsman.

I can't tell you anything about the casting number, but I wouldn't worry until Joe Lucia or someone else says it's a replacement. The larger numerals like the2 are common...it is very likely NOT part of the casting number.

[Wayne M.]

IMO, it's original

I don't have any hard examples or facts to present, and looking at Colvin's 1970-74 book he shows sidecover 3952648 for 1970 thru 1974 (end of Muncie production).

But on eBay (I know, I know) I see the 6-digit part # sidecovers for sale now and then, and the main difference that I can see is that the 1-2 shift lever has a tapped boss with a switch (like the 3-to-4 lever on the 3952648 covers).

The digit '2' in the casting is probably a mold #.

Hope others can add to this.

P.S. I have a 1971 assembly, OTC (over-the-counter) M22 (P1D19C) with a '648' sidecover, but the 3-4 boss is NOT drilled and tapped.

[Wayne M.]

IMO, it's original

I don't have any hard examples or facts to present, and looking at Colvin's 1970-74 book he shows sidecover 3952648 for 1970 thru 1974 (end of Muncie production).

But on eBay (I know, I know) I see the 6-digit part # sidecovers for sale now and then, and the main difference that I can see is that the 1-2 shift lever has a tapped boss with a switch (like the 3-to-4 lever on the 3952648 covers).

The digit '2' in the casting is probably a mold #.

Hope others can add to this.

P.S. I have a 1971 assembly, OTC (over-the-counter) M22 (P1D19C) with a '648' sidecover, but the 3-4 boss is NOT drilled and tapped.

[Rich Puleo]

Re: IMO, it's original

Hey guys,
The tag broke off, but the tab was there under the bolt head. This cover does have the tcs switch in place. I did check Colvin's book too, & also the judging manual, but no mention there. I thought I remembered reading something about this cover.
Thanks
Rich

[Rich Puleo]

Re: IMO, it's original

Hey guys,
The tag broke off, but the tab was there under the bolt head. This cover does have the tcs switch in place. I did check Colvin's book too, & also the judging manual, but no mention there. I thought I remembered reading something about this cover.
Thanks
Rich

[Wayne M.]

Here's one on eBay

This one has switch bosses on both 1-2 and 3-4 levers, but only the 3-4 has a switch.

http://cgi.ebay.com/ebaymotors/1973-4-speed-muncie-cover-no-335308-switch-rare_W0QQitemZ220201070214QQcmdZViewItem?hash=item220201070214

[Wayne M.]

Here's one on eBay

This one has switch bosses on both 1-2 and 3-4 levers, but only the 3-4 has a switch.

http://cgi.ebay.com/ebaymotors/1973-4-speed-muncie-cover-no-335308-switch-rare_W0QQitemZ220201070214QQcmdZViewItem?hash=item220201070214

[Joe L.]

Re: 1974 Muncie side cover question

Rich------

The sidecover used for 1970-74 Muncie transmissions was GM PART #3977618. That we know, for sure. What we don't know is just how many CASTINGS might have been used for this cover. We know that the GM CASTING #3952648 cover was used beginning with 1970. This cover has a boss and drilled and tapped fitting on the 3-4 shifter boss for the TCS system used for some 1970 models and all 1971-74.

However, I believe that there may be one of the few errors to be found in Alan Colvin's books regarding the casting number for the side cover used for 1973-74 Muncie applications. While the 3952648 CASTING was certainly used for 1970-72, I'm not so sure about 1973-74. I know, for sure, that at least some 1973-74 side covers used the GM #335308 casting number. For one thing, the GM #335308 casting number implies a 1973 release date for the part. I don't see any possibility that such a number would have been released well after 1974 (i.e. for SERVICE only). Plus, there would have been no need to release a revised casting after 1974 since Muncie manufacture ended during 1974.

Actually, I also believe that the manufacture of transmission case parts (i.e. main case, extension housing, mid-plate, and side cover) for Muncie transmissions ended either in 1974 or shortly thereafter. Regardless of what date may be found on a Muncie case BOX, I don't think the parts were actually manufactured after ABOUT 1974 (GMSPO often stores parts in bulk and boxes them periodically, as required).

So, I really think that it's very likely that some or, even, all 1973-74 Muncies used the 335308 side cover CASTING.

What's the difference between the 3952648 and the 335308? Well, the 3952648 has a boss on the 3-4 shifter boss for the TCS switch. The boss is drilled and tapped on every one I've seen and, in SERVICE, is supplied with a special plug for applications not requiring the TCS switch. The 335308 has a boss on both shifter lever bosses, but only the 3-4 is drilled and tapped. I've never seen a 335308 with a drilled and tapped 1-2 boss, but it's possible that some were. If so, though, I have no idea what such a fitting would have been used for.

[Joe L.]

Re: 1974 Muncie side cover question

Rich------

The sidecover used for 1970-74 Muncie transmissions was GM PART #3977618. That we know, for sure. What we don't know is just how many CASTINGS might have been used for this cover. We know that the GM CASTING #3952648 cover was used beginning with 1970. This cover has a boss and drilled and tapped fitting on the 3-4 shifter boss for the TCS system used for some 1970 models and all 1971-74.

However, I believe that there may be one of the few errors to be found in Alan Colvin's books regarding the casting number for the side cover used for 1973-74 Muncie applications. While the 3952648 CASTING was certainly used for 1970-72, I'm not so sure about 1973-74. I know, for sure, that at least some 1973-74 side covers used the GM #335308 casting number. For one thing, the GM #335308 casting number implies a 1973 release date for the part. I don't see any possibility that such a number would have been released well after 1974 (i.e. for SERVICE only). Plus, there would have been no need to release a revised casting after 1974 since Muncie manufacture ended during 1974.

Actually, I also believe that the manufacture of transmission case parts (i.e. main case, extension housing, mid-plate, and side cover) for Muncie transmissions ended either in 1974 or shortly thereafter. Regardless of what date may be found on a Muncie case BOX, I don't think the parts were actually manufactured after ABOUT 1974 (GMSPO often stores parts in bulk and boxes them periodically, as required).

So, I really think that it's very likely that some or, even, all 1973-74 Muncies used the 335308 side cover CASTING.

What's the difference between the 3952648 and the 335308? Well, the 3952648 has a boss on the 3-4 shifter boss for the TCS switch. The boss is drilled and tapped on every one I've seen and, in SERVICE, is supplied with a special plug for applications not requiring the TCS switch. The 335308 has a boss on both shifter lever bosses, but only the 3-4 is drilled and tapped. I've never seen a 335308 with a drilled and tapped 1-2 boss, but it's possible that some were. If so, though, I have no idea what such a fitting would have been used for.

[Rich Puleo]

Re: 1974 Muncie side cover question

Thanks everyone for the info!

[Rich Puleo]

Re: 1974 Muncie side cover question

Thanks everyone for the info!