Farmall Cub

There are 2 bolts loose where my right (long) axle tube meets the transmission housing. These two are on the back side, about half way up. As a result, I run low on transmission fluid all the time. I would like to repair this and have a little experience with helicoils. Can I make the repair this way? What size bolts are these? They look like 3/8 fine thread. If the helicoil goes in too deep will it bump into anything? I know I can break them off but I usually do not do that. Also, can I do the drilling/tapping through the axle housing flange or would I need to separate that? It looks to me like I can drill through both without taking the tractor apart. Not sure if this is a common problem. All advice greatly appreciated. I am planning the Spring tuneup and would like to resolve this issue. Thank you.

I'm not sure wht the two bolts being loose would cause the transmission to be low. I don't think thoese go all the way into the oil. Maybe you have enough play that the axle can move enough that is has blown the seal in the side of the transmission? You probably should pull the housing off and check it out before replacing those bolts. My guess is you need a seal. Also be sure to look for a groove in the shaft where the seal rides, you don't want to replace the seal only to find it still leaks.

It looks like those bolts are 3/8 - 16 x 1 1/8" long

As Daniel said, the bolts being loose shouldn't cause a leak. There is a seal in the transmission that is leaking. The axle tube should be dry (no oil getting into it). Also, are you sure you don't have too much oil in the transmission? There is a level plug on the lower left side, it only holds about 3 pints.