Fab 9 Inch
I have an Chassisworks Fab 9 inch rear-end with Strange third member that I am breaking in and want to know after the 500 mile breakend and gear oil change is it ok to switch the gear oil to synthetic (like Redline or Royal Purple). If you need more info: Rear has 4.11 gears and posi. Also what about the transmission oil. Rebuilt beefed up TH350 tranny with almost 500 miles in it too.