1969 F100 rear axle

[eod4647]

Fiest of many questions to follow, and hoping someone can help me out. Working off the data plate on the door I have 3.25 gears in the rea r axle. According to the tech artical it is a 3.3M axle (Ford WDM-H-S). What does that mean? Supposedly it has a "posi" in it, not sure what Ford's name for that is or if that code tells me it's a limited slip or not. I seem to recall from somewhere if I get both tires off the ground and turning one tire depending on which way the other turns you can tell if it's a limited slip or not. But I don't recall which is which...Thanks

[ultraranger]

A WDM-H tag would be for a 3.25:1 ratio, 28-spline axles, 9-inch ring gear with an open (single track) differential. --non-locking differential.

1969 was the first year for the Ford Traction-Lok differential. From 1968-back, a locking Ford differential would have been the Equalok Limited-Slip which is not as good a differential as the improved Traction-Lok. However, the '69 Traction-Lok is the worst version, compared to '70-'85, due to 4 large holes on the left half of the differential casting that makes the differential casting prone to breakage in this area.

http://www.fordification.com/tech/rearends_ford04.htm

[eod4647]

Thanks for the info. Once I get my daughter's car out of the garage i plan to check the truck over and change fluids and what not. I'll take a closer look at the rear axle at that time.