Rear End ? Driving me Nuts!
02-26-2012, 10:28 AM
#1
Senior Member
Thread Starter
Rear End ? Driving me Nuts!
I used Mobil 1 75-90 wt in my rear end (yes, w friction modifyer). Had someone tell me I HAD to use 75-140 or I would ruin my gears. I don't tow much (650lb quad (750!!
) and trailer less than 1k lbs total.
I realize (now) the spec was changed by Ford to 75-140....What you all think?
) and trailer less than 1k lbs total. I realize (now) the spec was changed by Ford to 75-140....What you all think?
02-26-2012, 01:21 PM
#2
I found out the same thing when I went to change my output shaft seals that have always weaped and finally started gushing. I'm guessing ford went with the lighter weight for fleet fuel economy and changed it as a result of the leaking seals. I would go with the heavier weight as I'm sure that ford wouldn't have back tracked from the original recommendation unless there was a problem with it.