Re: Differential oil. Best modern oil weight

Posted by Owen_Dyneto On 2017/1/18 18:28:39

With a proper seal, properly installed, and a shaft in good condition, your pinion seal should NOT weep.

As to gear oil, the multi-vis SAE 85W-140 type finds favor with many of us who don't want to change between summer and winter viscosities, I use it in both the '34 and '56 and have for decades. Brand is probably unimportant but I use Valvoline. But regardless of what your viscosity or supplier choice is, just make sure it's rated as Extreme Pressure, or EP, or hypoid gear type.

Replacing a rear pinion seal is a topic that's covered here very frequently. Rather than go thru it again, why not use the search function? You'll find excellent guidance on doing the job. If you want to use a heavy hypoid gear oil in hopes of minimizing the weeping, highest you should go is SAE 140, but not a great choice for cold weather operation. And I doubt it will cut down significantly on your leak.