rear diff gear oil weight for long trip...

[mikeny59]

Going to fl. f/ny and back. Not towing this time, but will have a lot of weight in the xj, plus twenty-hours straight driving.

Should I drop the standard weight Mobil 1 synth, and go to their heavier weight 75/140? Just installed new wheel bearings, fwiw...

Also, been using 10/30 religiously since new, again would a heavier oil be better? 117k on xj and runs as smooth as day one...

Thanks,

[Runnin'OnEmpty]

Mike, I think the M1 75W-90 is fine for the trip. Although I'd go up to the 75W-140 when towing.

I'd also stick with the 10W-30; it's fine unless the engine's using some oil.....
I use Castrol 10w-30 in mine.

[stewie]

the stock weight diff oil should be fine. i havent noticed any adverse effects when traveling in either of my vehicles.

[mikeny59]

I'd like to keep the stock oil, the M1 10w30 has been good to me, no oil usage. Motor runs perfect thus far.

Thanks, guys,,,