Re: Cross Shaft/Selector Shaft Seal

Posted by BH On 2011/12/12 21:47:01

Gator -

Thanks for the additional info.

My FAQ wasn't intended to be entirely conclusive, but can't be as I don't know of any supplier doing lab tests using an Ultramatic. It's merely meant to show that either Dexron or Type F will work, though they have somewhat different properties. Given the available info, the choice depends on what friction material are in your unit and how it behaves.

While I'm inclined to use synthetic wheel bearing grease (next repack), I just don't see sufficient advantage to synthetic lubricants for engine, transmission, and differential in antique autos.

Admittedly, synthetic fluids do last longer, but I've found them to be more prone to leak in vehicles that weren't designed with a synthetic product in mind.