Model 70 Transmission
 

What type of oil should go into the rear end/transmission of a model 70? I am rebuilding one and decided it would be a good time to replace the fluid. The oil that came out did not look as thick as 90 wt., but I don't know what it was.

Thanks

You can use Hy-Tran or 30wt oil. IMO, I'd rather use Hy-Tran.

over the 30 years or so I've been working on cub rear ends I've always noticed less rust on the parts if they had Hytran in them. I really noticed this in rear ends used for pulling where new gears were put in and you could see the effects over a period of time. the 30 wt just don't seam to cut it . above the fluid line rust would start to form on the gears during the off season as with the Hytran you didn't see that. stay away from heavy gear oils like 80-90 ect. you can get the generic Hytran at farm supply stores for a reasonable price

I too vote for Hy-tran. Unlike most of the fluids you could put in the tranny the hy-tran actually attracts and encapsulates the moisture. Those rears were nearly indestructable but do not do too well when moisture gets in there.