Confounding leak: What am I missing here?

[Brian K]

So the Scout's almost finished......except for this damn leak.

So:
1.) shift shaft seals replaced. No leaks there.
2.) transmission pan sealed perfectly. No leaks there.
3.) dipstick input tube sealed. Absolutely dry.

But,

at the very rear of the transmission, above the pan, an inch or two from dead center, there is a leak. In the photo, I've got the area where the fluid is coming from stuffed with a napkin. Give it a day and the thing is soaked. The leak is definitely coming from above the pan flange.

I'm flummoxed. Could it be the transmission case itself, maybe the gasket where the case meets the output housing?

Any advice from the experts would be very appreciated!

Thanks!

Brian

 

[Michael Mayben]

When you remove that napkin, you will see a "square"-shaped projection that is part of the transfer case adapter housing casting that hangs down slightly, right below the bolt hole. It's a segment about 3/4" x 3/4", you can slide a putty knife blade up between that segment and the pan rail about an inch as that segment does not seal against the rear of the case with the gasket.

That segment is a "stop" for a pivot pin for the low/reverse band linkage. It prevents the pin itself from walking out of the case, the pin is sealed in it's bore with either one or two "o" rings on it's circumference and if you remove the transfer case adapter, you will see it's end. Obviously the "o" ring is allowing a slight leak.

This pic shows the pin coming out of a case during an overhaul. While you can see two grooves, this one had only one "o" ring installed but that is not a problem if the single "o" ring is functional. That pivot pin does not move during operation.

This can be repaired by dropping the pan and removing the transfer case and adapter housing. Then you back off the rear band adjuster nearly all the way, ya don't want the link dropping out. No need to remove the valve body to do this, and the pin can be easily walked out using needle-nose pliers.

Since the tc adapter will need to come off, then that is the time to replace the back-to-back seals behind the bull gear that seal the output shaft.

I should have pics of all this stuff but not a step-by-step. I am doing sii tranny build right now though and can easily shoot any pics needed that I don't have.

As for the gasket and "o" rings, I have some spares here now I can supply ya by sticking the stuff in the mail. The gasket is just a plain old 727 tailhousing gasket and is not specific to that sii trans nor are the "o" rings, so a local tranny shop prolly has everything you need also.

 

[Michael Mayben]

This is another view of the pivot pin. This one is a "single" groove and requires only one "o" ring. All soft parts kits for these trannys contain only one replacement "o" ring, so I have several on hand that I use to add to a double groove pin if one is used. Before pushing the pin back into position, I lube it up with transemble or any form of silicone grease, use no other sealant of any kind on those "o" rings!!!!!!!! It will not leak once it's refreshed!

Some of the pins have an internal threaded hole in the end so that a bolt May be inserted and used to pull out with pliers or fingers. That also makes it much easier to re-install since you have a few parts that all have to be juggled into alignment simultaneously.

 

[Brian K]

Geez mayben, once again I'm indebted to that well of knowledge of yours. Thanks!

I'm going to tackle this. Hell, with the help of your FAQ's in this section, I've already done shift shaft seals, helicoiled pan threads, sealed dipstick tubes, adjusted bands, and changed the pan gasket twice.

I've bench-pressed transfer cases before, including the massive np202 on my fullsize, so it looks like this Dana 20's coming off and I'll be scheduling a workday for this project. And, I'lll get to put the fancy chrysler hard pan gasket back on the pan as I apologize to it for besmirching it's fluid-holding reputation when I blamed it on this leak.

I'll shoot you a pm about your offer on those gaskets/seals. It's very much appreciated!

 

[Michael Mayben]

I was short one of the bull gear seals (it takes two) so I picked up a re-stock yesterday in town. Ihon also has the seals (along with a replacement for the output shaft bearing) on the shelf also.

I have everything you need for this project on the bench now and will package and send out asap (two seals, two "o" rings, two gaskets, and a tiny supply of transemble to smear on the seal lips and the "o" rings. Since you are not in a big hurry...I've just come into a near-virgin radiator shroud for ya instead of piecing together the one I had in process. It will most likely be tomorrow before I have time to pull the rad/shroud out of the donor that is now squatted on the parking lot, all it will need is a clean-up and a fancy paint job so it matches the rest of yore shit! And a set of four of the chrome retainers for the shroud are headed yore way also. So I'll pack everything together and get it all sent down to ya in one box.

I'm sure you can git cindy to remove the transfer case for ya...and I know she'll have to twist the nut loose for the bull gear, I don't think you are man enuff to do that!

 

[Brian K]

Mm,

wow! That is fantastic! Thanks so much for sourcing that collection of transmission miscellany!

You found a fullsize fan shroud too?!! Before you box that up, be sure there isn't anyone who is in desperate need for it more than me. I know they are pretty "unobtainium" and mine is missing the lip making it harder to rebuild. Of course, I'd love to have it, But although chewed up, mine's still doing the job -- thanks to new dog-bone mounts from IH only holding that engine up.

hell, if you're making a regular box of the shipment, I'll buy a good used rubber automatic transmission shifter gaiter if you've got one o' them in a pile too. Mine's plenty perforated making the effect of a heater on at full blast pointed toward the knees.

I mean really, who wants sweaty knees?

Thanks again mayben, you're appreciated!

 

['74Louise]

I know this is an older thread, but I am new to scouts and am encountering my first issues with transmission problems. I seem to be having a leak from the same location and am trying to make this a diy. I read your diy reseal thread and will be tackling those seals at the same time. Is there somewhere to get a set-by- step for removing the transfer case and replacing those o rings? And do they have a specific name so I can order them from somewhere? Thanks for any help.