Before I hear the usual why wouldn't you "use what the Owners manual says" let me throw out who here is running anything close to a "stock" jeep, so poo poo on that argument. That being said for conversation purposes, cause its been slow these days around here, ha,ha, I'll ask who's running what in their AX5's or other manual gear boxes and T cases. Time to service both for me and Im pondering a few changes just because I can I suppose. The T case its been ATF since its birth. Im considering a 10/30 oil instead. The Trans has seen 90wt gear oil which was terrible in winter, so Ive been running a 30 or 40wt HD engine oil for the last year with fine results. But Im not thrilled running motor in it really. Im not impressed with Red lines products based off my own experiences so I'll avoid them. Ive been considering Mobil 1 Delvac SAE 50 Transmission oil which is GL1 thru 4 rated or??. Working with drives,gear boxes in industrial settings for 30 years Im really curious how one of the many synthetic ISO 100/AGMA rated lubes would do in a AX5 or 15 or other manual trans. Ive read lots of guys using that particular Mobil product in the Rams G56 manual trans with great results. As I said just a topic for discussion so fire away gents