Gear Oil Rear Differential Question

[clemsyn]

I changed the rear differential oil of my 1976 TE37 Levin. The manual stated 90w so I put a 80w-90 GL5. I started noticing leaks on my diff and looks like a pinion seal issue. I then rechecked the level and made sure the vent was fine. Then I read an article that in early 2000 they changed the viscosity of 90W and said that the old 90W is equivalent to like a 110w. I decided to try to put a 85w-145w in it and seems to be running fine with it. No leaks.

Would this damage my diff in the long run or would it be OK using the 85-140w GL5? Can I used half 80w-90W and 85-140W to make it closer to 110w?

[tojo]

80w90 and 85w140 are both thinner than 90w when cold. The higher figure in 85w140 means it preformes ( maintaines viscosity ) as a 140 oil when hot.

If you want to use a multigrade oil , I recomend 90w < ##

If Your te37 has Limited slip diff youll need an oil With slip (lsd) additives


Got a link to that article ?

[clemsyn]

Update:

I replaced my pinion seal and leaked stopped. I'm currently using just an 80-90W with limited slip.