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Changed the transfer case oil last week. Got back to it and found 1/2 cup of oil on the floor. I thought it was from the drain plug. Refilled and Teflon taped the drain and fill plugs being careful not to get the tape where it would be "in" the case.
Filled and just hung around for 30min. Drip, found out where the leak was from. The output shaft seal is shot.

Can this be replaced with only taking off the driveshaft flange or does the whole tailpiece need to be removed?

TIA!

You can repair it by removing the flange. Most likely the seal has worn some grooves into the shaft. You’ll want to redi sleeve it as well as installing a new sleeve. Not a hard job, as long as you have big cheater bars.

greeno wrote: ↑Sun Jun 18, 2023 5:01 am You’ll want to redi sleeve it as well as installing a new sleeve.

Redi Sleeve?? I'm not familiar with those. Its not on the IPB below. Please explain more on this.

Guess I'll have to see the condition of the output flange.

The sleeve is an aftermarket device, made of really thin steel and designed to slip over the damaged flange area and be seated with a drive collar and hammer. Simple to do.

The part of it that the collar rides on is then removed, leaving a new, smooth surface for proper sealing.

Some are also known by 'SpeedySleeve'. Google is your friend.

PoW

Redi-Sleeve is a Timken / National product: https://www.timken.com/products/timken- ... i-sleeves/

Speedi-Sleeve is from SKF: https://www.skf.com/us/products/industr ... edi-sleeve

But they are essentially the same thing, made from very thin stainless steel.

A couple of notes on the use of these sleeves:

1. Per Charles Talbert, use only with a new production seal. They do not work with the old leather OEM seals. (I don't have any personal experience using them with the leather seals, so am relying on Charles' expertise. Leather seals are a poor and obsolete design regardless.)

2. Apply some sealant to the shaft, especially on the grooved area, before installing the sleeve.

This Page helped me a great deal when I was replacing the seals on mine.

https://www.t137.com/ClintDixon/Seals/Seals.htm

Thanks all for the info, very helpful.

Here's the part numbers for the record
(Charles Talbert @M37Rebuild)

• Redi-sleeve / Speedi-sleeve number is 99212

• VITON oil seal number is SKF 21215 and must be the SKF brand

(The above #s should be for either the front/rear output shafts)

I will be visiting the local NAPA today!!

I also need to replace the seals on my 1952 M37 transfer case so I did some looking.
I used the M37 SNL G-741 parts manual which listed the number for the transfer case output flange seals (quantity 4 used) as Chrysler 927367 (CC-927367).

On the NAPA website I used that Chrysler part number 927367 and it came up with their part cross:
Pinion Seal - Rear Axle, Part #: NOS 21213, Line: NAPA Oil Seals
Spring Loaded w/ Auxiliary Dirt Lip, Inner Case, SKF Patented Bi-Directional Wave Seal, Positive Fluid Control, High Quality General Purpose Rubber, Temps from -40 Deg F to 250 Deg F.

I called SKF Tech Support (Rotary Seals Division) 888-753-3477 to verify the Chrysler to SKF cross. The person in the Engineering section verified that according to their data the Chrysler 927367 crossed to their seal SKF 21213. He said the 21213 has an extra “dust” seal/lip, but their 21210 has a single seal without the extra dust seal/lip and it would also work and be acceptable to use if you couldn’t get the 21213.

SKF: Chrysler 927367 crossed to SKF 21213 -
SKF 21213 Direct cross from Chrysler 927367 (Double-lip seal)
SKF 21210 Alternate part (Single-lip seal)

The above posts are correct. If the old seal has put a groove on the output flange shaft it will leak if you try to use the old flange with a new seal since the flange shaft is grooved and no longer “true”.

You have three options.
1. Have the flange turned down at a machine shop and use a new seal (not recommended for this case; too expensive).
2. Put a “Speedy sleeve” or “Redi-Sleeve” over the flange shaft, giving the seal a new smooth surface to seal to (but since this slightly increases the diameter of the shaft slightly it may cause a little more rapid wear on your seal – maybe. But certainly, a very viable option, except that seating the sleeve on the shaft may be a pain in the rear – might be something you can do or it may be worth having a shop do it, I don’t know).
3. Replace the transfer case output flange with a New Old Stock (NOS) flange (just make sure to check the part number for the flange you need and that you get the right replacement flange). I think Midwest Military, Vintage Power Wagons (VPW), Adirondack Dodge, and other vendors still have these for sale and they are very reasonably priced. This also ensures that the new seal “sees” the correct shaft diameter as originally designed and keeps you from buying and having to “press” the sleeve onto your old shaft.

Not saying this is the final word, just passing along information that I found.

Keep in mind the G741 series transfer cases can run almost 300F after a good highway run.

Gear oil viscosity at those temps can really thin out and might leak easier.

Synthetic oil is great from wear and longevity, but it can also sneak past seals, even new ones.

I've used Speedi-Sleeves over the years, and they do more to lessen oil leaks than just about anything else. Being only a few thousandths thick, seals don't even know they are there. They easily install with nothing more than a hammer and the included driver.

PoW

With Speedi-Sleeves (or similar) what sealant do you use to prevent oil from working between the sleeve and flange?

RTV?

None, it is an interference fit. Once you put one on you’ll see there is no need for sealant.