Congrats on the swap! I recently installed an 8.2 third/rear axle off a '13, and ECGS front, regearing to 4.56 and found the 85w140 recommended by ECGS was incredibly stiff in our subzero weather. Convo with them about it - they said ok to go lighter even during break-in given the local temps. So went to Lucas Dino 75w90 and much easier shifting. Gonna stick with that for front, rear and TC, as I've been hearing more and more people agreeing about non-synthetic for gears. But I may go back to 140 in the diffs for hard wheeling this summer in Moab - extra protection :rocker:Just have to say thanks for this write-up. My buddy and I tackled the rear 3rd on my 2007 this past weekend. A few "duh" moments but overall it went great. Going to stick with the 85w140 - it's what ECGS sent with the 3rd and their note with the shipment said to only use that.