I changed to oil yesterday it is leaking a little. I did a very thorough job of removing the old gasket material with a razor blade so I don't think that is causing the problem. I have retightened a couple of time but I really don’t think it would be wise to get it too much tighter. I did not use any gasket sealant. Is it normal to have a slight trip while the gasket swells up?

Is it leaking from the rear end cover? Does your tractor have the rear hitch plate? Did you put the three longer bolts in the bottom holes threw the hitch plate? If you put one of the longer bolts in a different area it will bottom out and not actually tighten up against the cover plate. There could also just be some old fluid between the hitch plate and the rear cover, Spray it down with some brake cleaner, but beware some times it can soften and eat the paint.

Yes it seems to be leaking from the rear end cover at the very bottom. I did make sure to use the long bolts on the hitch. I thought about the fact that it could be oil that is stuck between the hitch plate and the rear end cover but it seems to be a little too much for that. I will spray it down to make sure. How tight should the bolts be?

If the cover has been over tightened during it's life, it will get distorted and weep/leak
I like to open the vice jaws a inch or so and and using a larger hammer, smack the cover right @ the bolt holes just enough to flatten the bulge caused from overtightened cover bolts.
It works for any metal cover.
It don't hurt to go just a tad more than flat, as the bolts will pull it flat.
Now don't get crazy here, your just trying to restore a cover to flat.
This is pretty much standard procedure for auto/truck oil pan,rocker covers etc, or any cover that gets "puckered in" from too tight a bolt.
Prolly' you will be lucky and be able to reuse your new gasket.

The cover did not appear distorted at all, it was perfectly flat. I am actually shocked it is leaking. I really hope I dont have to pull the cover to get this fixed, I dont know how I am going to save $40 worth the Hytran.

I don't like to use "sealers" on that gasket, but, I do put a small amount of grease (chassis lube) on that gasket at assembly.

If there is a small place that might leak, the grease finds it before the Hy-Tran!!

The grease will even "seal" a used gasket nicely.

Are there torque specs for the rear end cover?

Yes they are in the service manual in the tech section of the site.

Thanks, I was hoping to not have to sift through 145 pages to find it. Does anyone know off hand what the torque spec for the rear end cover are?

There's a chart in the first couple pages of the service manual that has the torque values for all fasteners, bolt grades, materials, etc.