Maytag 806 transmission o ring question

[sprog]

I'd like to leverage the power of the collective mind...

After rebuilding a Maytag 806 helical transmission (circa 1979) I noticed transmission fluid dripping from the brake package area. This started ~1 year after a complete overhaul. My best guess is that I chose the wrong o-ring material, silicone, for the lower shaft seal. I've since read that silicone may prematurely degrade upon exposure to transmission fluid.

So faced with pulling out the transmission, and replacing the o-ring... AGAIN, are there any o-ring material suggestions?

I was thinking FKM (fluorocarbon elastomer). Perhaps nitrile?

Any comments, suggestions?

Thanks in advance,
Chris

P.S. I included images of before and after it was cleaned up.

 

[lowefficiency]

It's always interesting to see how many variations Maytag made of that internal gear set over the years. They really did experiment with a lot of different techniques and manufacturing methods along the way.

For the o-rings, I believe they are still widely available from the online parts supply companies? No idea on the specific material compositions, but if in doubt, you could just get the official Whirlpool parts...

 

[qsd-dan]

Maytag used a neoprene o-ring, at least in the later years, anyway. Not sure what they were using back in the 1950's.

It's kind of an odd ball size. Best to use the real deal while a some are still floating around.

A tip on getting maximum life out these o-rings:

Once the o-ring is in place, pour a couple of ounces of transmission oil down the transmission tube housing from the top and let drip down out the bottom. Liberally lubricate the lower shaft and install it from the bottom, carefully twisting the shaft once it meets the o-ring. Extend the shaft up a few inches higher than it needs to be and pool another couple of ounces of transmission oil inside the transmission around the shaft, then lower the shaft back down to the proper position. That o-ring needs plenty of lubrication or it'll burn itself out in 10 or less years.

Over the years, I've pondered about using grease on that o-ring to extend its life but haven't got the chance to experiment with that theory yet.

Pardon Our Interruption...

 

[sprog]

Dave, Dan,
Thanks!
I'll go OEM for the next iteration.
Dan, thanks for the link. I'll follow your workflow.

I also used Red Line MT-90 transmission fluid. Could this have been a problem?

Thanks again,
Chris