Gear oil for trans and rearends

[Rawze]

I agree.. pukas is not a good thing to add as a thickener.. and 50wt is too thin for rear ends unless you live on the extreme north pole or something.

Simply running some 80-90wt, or even better, some 85-140 in them if ya go all 48-states, or heavy-haul, would make em last quite a bit longer.

Just as a reference: I ran ~80/90wt synthetic in mine and replaced the rears due to wear at roughly 1.13 million miles finally... though they were still ok. I just did not want one laying down on me or binding up, etc. without warning.

(Synthetic or not synthetic)...
Synthetic has absolutely no advantage as far as longevity or change intervals is concerned. It is a bit more costly to use synthetic oil in the rears and tranny.

However in rear ends, and usually the tranny, ... because there is no way for them to maintain a steady operating temp,.. Synthetic is still recommended in those components. This unless you only drive in the south and do not do a lot below-freezing winter driving.