Differential oil weight

[Ghstrydr]

I am getting ready to Change my front and rear differential oil and looking at what is recommended. I have a Dana 30 in the front and a Dana 44 rear. The chart shows I can use 80w90 in both or 80w90 front, 75w145 rear. I was going to do the latter, however is there any harm using 75w145 in both? The 75w145 is synthetic while the 80w90 is Dino oil.

 

[BLACKJKU]

I am getting ready to Change my front and rear differential oil and looking at what is recommended. I have a Dana 30 in the front and a Dana 44 rear. The chart shows I can use 80w90 in both or 80w90 front, 75w145 rear. I was going to do the latter, however is there any harm using 75w145 in both? The 75w145 is synthetic while the 80w90 is Dino oil.

If you live where it's cold alot of the time you don't want the heavier oil.

 

[Ghstrydr]

If you live where it's cold alot of the time you don't want the heavier oil.

I do live in the North East where is does get and currently is cold so I'm thinking I will go with the 75w140 Synthetic oil in both the front and rear differentials.

 

[Ghstrydr]

So I decided none of the above. We rarely see temps in the upper 90`s and I don't tow anything but a 6' utility trailer and that's short distances and seldom. This eliminates the need for 75w145. However, the temps do get very cold in the winter so I'm going to use Mobil 1 75w-90 full synthetic in both differentials.

 

[BLACKJKU]

So I decided none of the above. We rarely see temps in the upper 90`s and I don't tow anything but a 6' utility trailer and that's short distances and seldom. This eliminates the need for 75w145. However, the temps do get very cold in the winter so I'm going to use Mobil 1 75w-80 full synthetic in both differentials.

Sounds like a good choice.