Planning on a diff service on my truck this week and up until now, I thought 75/90 went in the diff... Upon doing my research, I see it's 75/140.

Do you guys really use the 140? I'm in South Mississippi so I'm sure it'll be fine. I'm just curious if you guys used any other weight.

3.55 9.75" LSD. Yes I also have the friction modifier.

 

140 rear. Rear was pretty easy.
90 front. Front...I just used a hand siphon. Drain and replace.

 

The rear calls for 75w140. I currently have Lucas Syn in there with no complaints.

 

75/140 it is then. I was just wondering how the clutches handled it... I know the bearings aren't too picky as long as they have some kinda oil on them.