Want to make sure Im buying correct gear oil for differentials

[SuperOldSchool]

Put 75w90 in both and call it a day. The key is it’s fresh with additives and clean.

I put Amsoil Severe Gear 75w90 in both boxes at 39k and will do again at 100k

No need to overthink this one.

 

[wjburken]

No need to overthink this one.

But, overthinking is what we do best here. Just ask @Rocket Man and @iamdub. They have both done PhD Dissertation level research into this exact topic because Inquiring Minds want to know!