T10 Tailshaft Plug Question...

[Jill J.]

Does anyone know what the correct plug for the tailshaft of a T10 dated December 58 is supposed to look like? I've attached a picture of the tailshaft with the hole outlined in red. I've also posted the 2 plugs I have. They're similar, but different. Or does anyone have a picture they can post of what the plug is supposed to look like in the tailshaft?

Thanks.

Jill, 59140

[Joe R.]

Re: T10 Tailshaft Plug Question...

Jill,

If someone doesn't post an answer you could call Danny Nelson in Greensboro, NC at 1 336 621-4327.

JR

[David B.]

Re: T10 Tailshaft Plug Question...

Information taken off the original 4 spd. extension blueprint dated 11-3-56 and revised 11-22-57 lists this as PN # 3744184 it is listed in the '57 master parts manual under Group 4.317 as Bolt, retainer (1/2 - 13 x 1 1/8). Did not have time to provide a profile but hope this info heads you in the right direction.

[Bill M.]

Re: T10 Tailshaft Plug Question...

My 9/58 tailhousing has the dimpled flat plug; concave surface facing out (to the vehicle rear).
I can see I had some sealer around the plug. It must have been leaking there, so add some sealer in the recess before installing the plug.

[Wayne L.]

Re: T10 Tailshaft Plug Question...

The flat plug is correct, and I second the nomination for sealer.

[Jill J.]

Re: T10 Tailshaft Plug Question...

Thanks a lot for your responses. This really helps me out!! :-)

Jill, 59140

[David B.]

Re: T10 Tailshaft Plug Question...

Fairly good photo on page 40 fig. 65 of "Corvette Service Operations, Chassis Booklet" dated August 1957 details rebuild of 4 speed transmission. Appears to be a cup plug (your 2nd version) with much shorter flanges/lips. Instructions call for using sealer when being installed. I think NCRS sells a reprint of this manual. A ton of revisions were made during this time period on the 4 speed and my eyes might be deceiving me so you be the judge.

[Bill M.]

Re: T10 Tailshaft Plug Question...

My 9/58 tailhousing has the dimpled flat plug; concave surface facing out (to the vehicle rear).
I can see I had some sealer around the plug. It must have been leaking there, so add some sealer in the recess before installing the plug.

[Jill J.]

Re: T10 Tailshaft Plug Question...

Fairly good photo on page 40 fig. 65 of "Corvette Service Operations, Chassis Booklet" dated August 1957 details rebuild of 4 speed transmission. Appears to be a cup plug (your 2nd version) with much shorter flanges/lips. Instructions call for using sealer when being installed. I think NCRS sells a reprint of this manual. A ton of revisions were made during this time period on the 4 speed and my eyes might be deceiving me so you be the judge.

Thanks for the additional info, David. I really appreciate it.

Jill, 59140

[Jill J.]

Re: T10 Tailshaft Plug Question...

Thanks for the photo, Bill. Just to clarify, when you say the "dimpled flat plug" you're talking about the first picture (curved, thin plug) next to (or to the right of) the tail housing picture that I provided, correct? And not the thicker one...?

When we tried the curved, thin plug last night it's pretty loose. If that's the one, I can see why it might have a problem leaking.
When we tried the thicker one, we'd have to remove some of the "thickness" and we'd have to put it in the freezer before installation because it's a fairly tight fit.

Thanks.

Jill, 59140

[Bill M.]

Re: T10 Tailshaft Plug Question...

Thanks for the photo, Bill. Just to clarify, when you say the "dimpled flat plug" you're talking about the first picture (curved, thin plug) next to (or to the right of) the tail housing picture that I provided, correct? And not the thicker one...?

When we tried the curved, thin plug last night it's pretty loose. If that's the one, I can see why it might have a problem leaking.
When we tried the thicker one, we'd have to remove some of the "thickness" and we'd have to put it in the freezer before installation because it's a fairly tight fit.

Thanks.

Jill, 59140

Hi Jill:

My T10 has the curved thin plug and the plug has never been removed from the transmission, but it still leaked...

Bill

[Steve G.]

Re: T10 Tailshaft Plug Question...

The thin concave plug is put in concave out then hit with a ball peen hammer in the centre (causing the dimpling) which causes the plug to expand and lock into the bore. Always use a sealant. I would use a locktite flange sealer.
Steve

[Jill J.]

Re: T10 Tailshaft Plug Question...

Thanks Bill and Steve. Guess what I'll be doing this weekend, along with my fiberglass work...

Jill, 59140

[Steve G.]

Re: T10 Tailshaft Plug Question...

One other thing, in reference to the comments about these things leaking. The trick to getting a nice, dry, sweat-free seal on anything is to ensure there is absolutely no trace of oil anywhere. Use an aerosol brake cleaner and blow it off with air. Do it at least twice so you are sure to get all of it.

Some sealing methods tolerate oil better than others, but all benefit from an oil free surface. Silicone sealer with any trace of oil is a waste of time. But even gaskets, of any material type, will create a much better seal on a completely oil free surface.

Steve

[David B.]

Re: T10 Tailshaft Plug Question...

To verify the size of this expansion plug General Motors Engineering Standards lists this as Part # 106517. It's diameter size is 1-1/8 with a average thickness of .083 and plain steel. It MIGHT even still be available at a GM dealer. Installation method is as Steve Garner mentioned.