Drive-shaft Question:

[Captain D]

Hi all,

When making a routine check under the car for any fluids before I set out on the road, I noticed that my 69' Charger's 727, 3-speed automatic drive-shaft had a few drops of red tranny fluid underneath where the unit connects to the tail end of the transmission. Everything is perfectly clean and dry at the main seal where the yoke (correct terminology?) secures into the tail-shaft of the transmission. The slight leakage is actually not at this main seal, but at the joint just past this main seal area (the section that essentially looks like a hinge). The questions that I have are:

1.) Although it doesn't look like it takes one, is there some form of seal or plug at this point? I suppose it must to explain the leak.
2.) If so, how expensive of a repair are we talking about? I'm hoping that it's an easy / inexpensive job and the whole driveshaft doesn't have to be dropped.
3.) And, what is this part called exactly (this 'hinged' location of the drive-shaft)?

This car does this to me every time - just before a vacation 'something' decides it wants to act up and ruin a trip because it knows that my mind will keep harking on it. Since I'm unsure of all the terminology just yet, I can certainly try to snap a picture if my written description didn't make too much sense. Thank you for any and all replies,
Aaron

   

[John_Kunkel]

The "hinged" part is called a universal joint or u-joint. It connects the driveshaft to the slip yoke that plugs into the rear of the transmission and, yes there is a plug in the rear of the slip yoke that can leak or, in rare cases, may be totally missing.

[Captain D]

Thanks John for the reply + info,

I have a standard tail-shaft seal on order from Auto-Zone ($20). However, I'm not seeing any runs from this seal down towards the universal joint / u-joint. So, it 'may' be this plug going bad after all. I'll call round' tomorrow after work to see if I can order one of these plugs (unsure what it's name is exactly) to have on-hand as well. But, in the meantime, is this the 'plug?' If so, my 727 trans. is a 3 speed, automatic:

http://shop.advanceautoparts.com/p/national-redi-sleeve-99187/3271757-P

Thank you again,
Aaron

[John_Kunkel]

No, the plug is the round disc shown in the pic, it is often called a "soft plug" or "freeze plug". Some early slip yokes have a vent hole in the center of the plug, not correct for your year but could have been installed.

[Captain D]

Thanks again for the reply,

Okay, I got 'on the horn' with the local shops and Advance Auto informed me that the plug is also called: an 'engine oil galley plug,' an 'expansion plug,' and a 'rocker arm shaft plug.' I found one and we think that this is what I may be in need of. However, if it is the correct part, there are variances in size - yet, all the different sizes say that it'll fit a 69' Charger. And, the prices range from $3.99 to $35.00  . Any idea which size I may need for a 69' Charger and what the difference is based on these wide price ranges?

Are we getting warmer with this recent find?:

http://shop.advanceautoparts.com/p/dorman-autograde-steel-cup-expansion-plug-1-in.-sc-height-0.250-555-018/16140179-P?searchTerm=freeze+plug

Thanks again, as well as any info on which size I may need if this is the correct item,
Aaron

[John_Kunkel]

There are two types of soft plugs, the "cup" type as in the link you furnished which has a raised rim that actually makes it like a cup or the domed flat plugs (correct named is Welch plug) as in the pic below. The slip yoke plug is a Welch plug.

At any rate, you're getting ahead of yourself....determine the origin of the leak before ordering any parts. A leaking rear plug in the slip yoke should be visible without removing the driveshaft, spray some Brake Kleen into the area and watch for the leak to reappear.

[Captain D]

HI there John,

Many thanks again for the reply + info! Yes, I did the same - sprayed it with some good ol' fashion brake cleaner (before any parts were ordered / purchased) and it seems that it is has some very slight seepage from this 'soft plug' seal (like a drip or less per day - I just like to address small problems before they become bigger problems later on down the road). I talked with a local shop that can do the work and they noted that the plugs can be a bit of a challenge to locate since they don't typically go out very often. Although I feel that it's kind of a 'band-aide' fix, they suggested simply cleaning it up real good with the brake cleaner, wiping it down, etc. and merely applying some 'Right Stuff' one-minute gasket maker, by the brand Permatex first before going through the trouble of replacing it altogether since all there is is a very thin seal around this plug and repop stuff may not work the greatest anyway. I informed him that it's a good tip, but I'd like to try and try replacements if at all possible nonetheless.

So, that's the update so far...

Thank you for all of the info and chat soon,
Aaron

[Captain D]

...closest match found was this expansion plug:

http://shop.advanceautoparts.com/p/dorman-autograde-steel-cup-expansion-plug-39-64-in.-sc-height-0.200-555-067/22140563-P?vehicleIdFromReq=-1&isAllVehicle=true&vehicleIdSearch=-1&searchTerm=555-067&showTitle=

[John_Kunkel]

You keep linking to the cup-type soft plug. Look at the pic I posted, the plug is almost flat i.e. slightly domed.

Since you can't determine the actual size of the plug without removing it, the goop idea is the best solution.

[Captain D]

Unfortunately, the 'cups' are the only rocker arm shaft plugs that I can get it seems. I'm not too fond of 'gooping,' but I agree with you = it's an option til' I can find either a better part or new driveshaft altogether.