No odometer and squeal from rear
I have a 1995 Ford Ranger with a 4.0 manual transmission. About 6 months ago at 109,878 miles the odometer and tripometer stopped. The speedometer still works, though. Recently, I have heard a sqealing noise when I am backing up in the morning and it sounds like it is coming from the rear differential area (at least that is where it sounds from the cab). I was going to check the fluid level in the differential, but couldn't find a port. Can anyone tell me where to find the port and any ideas about the odometer/tripometer?
Thanks in advance,