Cub Lo Boy rear final drive oil level

[WVScott]

Good evening all.

I recently rebuilt our 57 Cub lo-boy and noticed I am getting an oil leak at both rear axle seals (closest to where they meet the wheel to bolt the rim on). They were both replaced with new seals so I was sort of surprised they they both seem to wee oil. When I filled the rear diffs I did so to the fill plug bottom, is that incorrect on the low boy? I was thinking I may have them overfilled and thus the leak.

I also noticed I have a few drips coming from the area under the throwout bearing. I did soak the new throwout bearing for a week in a pan of oil so I am not sure if the oil is just coming out of the bearing from the test run or if I have another issue. The rear main seal was replaced and it does not appear to be coming from the engine side so I don't believe that is my issue. Does anyone know if this is normal? If it is not I am wondering if I am getting some leakage from the transmission side and it is coming down the main shaft toward the motor. (The oil appeared to be motor oil however so that is why I was doubting that).

Any thoughts are appreciated.

[Crimson Tim]

Pretty sure I’ve read on here that the fill holes only work for the standard Cub where the finals are upright. I think you have to just measure what you’re putting in for the lo boy, but someone who knows for sure will surely chime in with the correct procedure shortly.

Edit: nope. Looks like I stand corrected and should have kept my mouth shut. See below for people who know better!

[WVScott]

I was thinking I may be overfilling it and thus causing my leaks but I really was not too sure. My manual said use the fill hole but it is not specific to the Lo boy.
Thank you

[Glen]

Hi,
That is the correct level to fill LoBoy final drives, up to the oil filler plug hole, on the rear facing side of the final drives.
Below is the 1957 LoBoy operator's manual, it has lots of info. There is a table of contents on page 1.
The lubrication section begins on page 21.
The lubrication guide is on page 25, and shows the places to lubricate. The pages after page 25 explain how to lube them.
It tells about checking all the oils in a LoBoy.
https://farmallcub.com/rudi_cub/www.cle ... index.html

If the seals leak, something probably needs repair. The gaskets between the seals and the housing, at the 4 bolts, may be leaking. I would check with a light and see if you can see where they leak.
The gaskets may need sealer on both sides of them. If they need sealer, you would need to clean all oil off the parts so the sealer will stick to the metal.

Below is a picture from TM Tractor Parts showing the oil fill and level plug. The housing is turned on it's side, it is the right final drive.

[WVScott]

Thank you. That seal and the gasket were replaced but I did not use sealer on it so that could be my issue. I think I will run over and get the heat turned on in the shop so I can investigate more this afternoon. THANKS

[radioguy41]

In Glen's link above page 29 contains the info you want.

Click on image for a larger view.

[WVScott]

Thanks. I ended up draining it down a little and pulling the seal/plate and gasket off toward the wheel an inch or so. After cleaning it all up, I put a thin coat of form a gasket on both sides and bolted it back up. Seems to have solved the problem without me tearing all down again and damaging the paint. Not sure why it did not seal the first time with the brand new gasket but all is good now. Thank you all for the help.

[Gary Dotson]

It’s a pretty safe bet that that seal retainer plate is no as flat as it once was, hence the need for sealant.

[WVScott]

Lol - you are correct! I myself and a bit more rounded than I was years ago.....