1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

[Scott S.]

The 1967 AIM shows the transmission mount is GM # 3792133 (UPC 6, Sheet B6, Item 1). The transmission mount that came off my '67 L79 with M21 has the 3792133 part number molded into the rubber, along with a few other numbers:

M 2 17 (followed by a symbol)
over
3792133 BLACK
over
3913198 YELLOW

On the other side it says:
1246118 WHITE
over
3913498 YELLOW


If this is the original transmission mount or a correct older replacement, how do I tell whether it's reusable or if it should be replaced?

[Scott S.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

A few more pictures. In picture four, the rubber "cover" is torn or cut in the shape of the open end on the other side (e.g., picture 3).

.

[Joe L.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

A few more pictures. In picture four, the rubber "cover" is torn or cut in the shape of the open end on the other side (e.g., picture 3).

.

Scott------


This MIGHT be an original piece but I kind of doubt it. I don't think that the 3913198 or 3913498 part numbers would have been on a piece originally installed on your car. Those are not Corvette-utilized part numbers but they were released a little after your car was built. Actually, those part numbers were discontinued in the 1968-1969 period so they did not "live" very long but I think they may have remained on the parts manufactured after that time.

In any event, whether this is the mount originally installed on the car or a later replacement, it is a GM piece. It LOOKS to be in pretty fair shape but looks can be deceiving for parts like this mount. However, the ends do not indicate any problem. That is how these mounts are even when brand new. There may or may not be a "skin" of rubber over the void in the center of the mount. Whether the "skin" is present, or not, makes no functional difference.

So, should you use this mount? Well, if new GM mounts were available OR if there were aftermarket mounts of OEM quality available, I would say no; always use a NEW mount when you have removed a mount and it's been in long-service. However, there are no GM mounts available and I don't know of any aftermarket of OEM quality.

Thus, we have a real "conundrum" on our hands and I have no definitive answer. The question is whether your old GM mount is better or not than a new mount of what's available today. I have no answer for that.

[Scott S.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

So, should you use this mount? Well, if new GM mounts were available OR if there were aftermarket mounts of OEM quality available, I would say no; always use a NEW mount when you have removed a mount and it's been in long-service. However, there are no GM mounts available and I don't know of any aftermarket of OEM quality.

Thus, we have a real "conundrum" on our hands and I have no definitive answer. The question is whether your old GM mount is better or not than a new mount of what's available today. I have no answer for that.

Hi Joe,

Is there any difference between my current (old) transmission mount and the transmission mount used on a 1967 Buick Skylark with 300 or 340hp engine, which I have also seen labeled as GM # 3792133?

Would an NOS example of the Buick part with that number (3792133) on it be the same as the Corvette part, and therefore an OEM quality part that is functionally interchangeable?

[Joe L.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

Hi Joe,

Is there any difference between my current (old) transmission mount and the transmission mount used on a 1967 Buick Skylark with 300 or 340hp engine, which I have also seen labeled as GM # 3792133?

Would an NOS example of the Buick part with that number (3792133) on it be the same as the Corvette part, and therefore an OEM quality part that is functionally interchangeable?

Scott------


The GM #3792133 mount did have Buick applications. However, I do not know if the 1967 Skylark was one of them.

In any event, IF the NOS mount is a GM #3792133 it will work perfectly for your application. There is absolutely no difference between a part of any particular part number with regard to the car or truck it is used on. So, if a part is a 3792133 it will work perfectly for ANY application for which that part is cataloged.

The question is whether the part actually is a GM #3792133. If there is a GM parts label on it which says that it's a 3792133, then that's what it is. If it's in a GM box with that part number on it, then that's what it is (providing no one has switched another part into a box with 3792133 on it).

You will note from your mount that there are several part numbers on the mount. Each of these represents a similar but different mount. You will note that after each part number is a color. When new, the mount will have a grease pen mark of the color indicated for each part number, usually with the grease pen mark over the part number. That indicates which of the several part numbers the particular piece is. The 3792133 is indicated by "black" which means there is no colored mark if the part is of that part number. Any other colored grease pen mark and the part is NOT a 3792133.

[Scott S.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

Scott------


The GM #3792133 mount did have Buick applications. However, I do not know if the 1967 Skylark was one of them.

In any event, IF the NOS mount is a GM #3792133 it will work perfectly for your application. There is absolutely no difference between a part of any particular part number with regard to the car or truck it is used on. So, if a part is a 3792133 it will work perfectly for ANY application for which that part is cataloged.

The question is whether the part actually is a GM #3792133. If there is a GM parts label on it which says that it's a 3792133, then that's what it is. If it's in a GM box with that part number on it, then that's what it is (providing no one has switched another part into a box with 3792133 on it).

You will note from your mount that there are several part numbers on the mount. Each of these represents a similar but different mount. You will note that after each part number is a color. When new, the mount will have a grease pen mark of the color indicated for each part number, usually with the grease pen mark over the part number. That indicates which of the several part numbers the particular piece is. The 3792133 is indicated by "black" which means there is no colored mark if the part is of that part number. Any other colored grease pen mark and the part is NOT a 3792133.

Thank you very much for the explanation Joe, I will ask about the box and/or any grease pen mark. It was described as a Buick transmission mount, but with the 3792133 part number, so I suspect it is a Buick-only application with a rubber center section that was generic to several different steel transmission mount section applications (the steel part that the rubber is vulcanized onto), if I understood what you are saying correctly.

[Joe L.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

Thank you very much for the explanation Joe, I will ask about the box and/or any grease pen mark. It was described as a Buick transmission mount, but with the 3792133 part number, so I suspect it is a Buick-only application with a rubber center section that was generic to several different steel transmission mount section applications (the steel part that the rubber is vulcanized onto), if I understood what you are saying correctly.

Scott-----


The only question is whether the mount is or is not a 3792133. If it is a 3792133 then it is the correct mount, whether it also fits a Buick or not.

[Chuck S.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

Thank you very much for the explanation Joe, I will ask about the box and/or any grease pen mark. It was described as a Buick transmission mount, but with the 3792133 part number, so I suspect it is a Buick-only application with a rubber center section that was generic to several different steel transmission mount section applications (the steel part that the rubber is vulcanized onto), if I understood what you are saying correctly.

What Joe is saying is the rubber portion may be applied to any number of different steel mounting plates, and ALL those possible configuration part numbers are molded into the rubber.

The appropriate part number for that particular configuration is identified by a grease pencil mark on the part of the same color description molded into the rubber behind the appropriate part number.

For example...if the part has NO grease pencil mark, it's 3792133; if it has a yellow grease pencil mark, it's 3913198. If you're talking to a seller, I would ask him if the part has any grease pencil marks, and the color, before you tell him it should have no marks.

[Scott S.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

What Joe is saying is the rubber portion may be applied to any number of different steel mounting plates, and ALL those possible configuration part numbers are molded into the rubber.

The appropriate part number for that particular configuration is identified by a grease pencil mark on the part of the same color description molded into the rubber behind the appropriate part number.

For example...if the part has NO grease pencil mark, it's 3792133; if it has a yellow grease pencil mark, it's 3913198. If you're talking to a seller, I would ask him if the part has any grease pencil marks, and the color, before you tell him it should have no marks.

Hi Chuck, thank you for the clarification, I will contact the seller and post what I find out.

Happy Thanksgiving everyone,

Scott

[Scott S.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

I contacted the Seller and he said it has "3792133" stamped in the rubber. I explained about the multiple part numbers and the grease pencil, but he didn't sound too sure about all that, just that if it has the correct part number according to the GM parts book, then it should work. They have a return policy so I ordered it.

It arrived today, and it appears to be identical to the one that came off my car, except the one on my car had the four part numbers molded into the rubber, while this NOS transmission mount has only "3792133" molded into the rubber. Also, the rubber on the top of the NOS part is "formed" better and sticks up higher, I'm guessing that's because it hasn't been compressed under a transmission for the last 43 years. There was no GM box or other identifying marks that came with the NOS unit.

Is this the real deal and the right part?

[Scott S.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

The example that came off the car weighs 21.7 ounces, the NOS unit weighs 20.7 ounces.

[Scott S.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

Last two pictures:

1) unit that came off the car (side view, showing rubber compressed at an angle)

2) NOS unit (side view, rubber at even height across the top)

[William C.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

No difference, GM used that mount in a variety of applications, look at Chevy pass cars Chevelle, etc for more examples. New one is likely lighter because it hasn't sucked up oil and dirt for the last 40 years.

[Wayne M.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

Interesting thread -- never realized there were so many variations on rear drivetrain (trans) mounts, even though the dimensions seem identical (ie. 3_3/4" bolt center-to-center, to mate with Muncie tailhousing, and 1_1/2" for the holes that bolt to X-member bracket. I wonder why ? different flexibility to tune out vibrations ? I doubt GM was that sophisticated .

I have one here (don't know what its history is) with characters molded into the rubber "2224 BLACK", underneath that "25"; then, on other side "2155_A H" and under that "RED".

[Scott S.]

Re: 1967 transmission mount (4-speed) GM # 3792133 - reuse or replace (with what)?

No difference, GM used that mount in a variety of applications, look at Chevy pass cars Chevelle, etc for more examples. New one is likely lighter because it hasn't sucked up oil and dirt for the last 40 years.

Hi Bill, thanks for the reply. I had not seen a "new" example of these transmission mounts before, and considering all the parts that are unique to Corvettes, I wanted to be sure this was the correct transmission mount.


UPC 6-B6 shows the transmission mount installation, rubber side down onto Bracket # 3820372. On the old (used) transmission mount, is the compressed rubber across the top section sloped (compressed) downward at an angle toward one end because of the transmission twisting with the engine (torque) during acceleration?