Gear Lube for Troy Bilt Horse

[Bob in MO]

Bought a used Horse this weekend. Need to put some gear lube in it. From what I'm reading on the forums I do not want to put any GL-5 products in it. So I'm looking for SAE 140wt.
Anybody know where to get this stuff?
Most places are saying to use 85w-140 but I think it says on the container that it is GL-3, Gl-4, and GL-5 rated; is this a problem?
Thanks in advance

 

[Saxman]

Bob,
It does take 140 wt gear oil. I got mine at an auto supply store and I forgot the rating GL-5 or 4. I guess you don't want the GL 5 because of the bronze gears? Tell us about your Horse, year, engine, etc. They are great machines.

 

[Bob in MO]

Looks like its got the original 6 HP Tech. engine. The serial number is 421081. I called troy Bilt or mtd whoever they are and they said it was probably between a 78 and 82 year. Engine idles a little ruff, gonna have to take a look at that. Came with a dozer blade. Thats about it.