Gear Oil for TruTrac?

I decided to go with the TruTrac and am going to install it back in the Dart today...I have heard pros and cons about using synthetic oil with this type of rearend (because of the fact that it doesn't have clutches). Does anyone have this diff and run synthetic? I was planning on running RP 75W-140 because that's what I had used before...anyone have any input?

Thanks!
Craig
Author: admin