i have a 1980 F-150 and i want to know what size rear end and gear ratio it has so i can change it out with anouther....the tag on my rear end says WDM-CK OE08
3.25 9 S/317/A

and the the one on the 1986 F-150
S810P
3.55 8 8 6f09

I just want to know what sizes they are,if they are posi and if i could switch them around with little problems.

 

WDM-CK, according to my sometimes wrong decoder:

F100/150 '79-'82. 3.25 ratio, non-limited slip, 31 spline axles, 9" ring gear.

Your tag already tells you it's a 3.25 non-limited slip, as the tag would read "3L25" if it were limited slip.

S810P:

F150 '84-'86, 3.55, non-limited slip. 8.8" ring gear.

These are two different designs. The 9" has a drop-out carrier. The 8.8" is an integral carrier. Maybe a couple of bolts interchange between the two. You would have to swap the entire axle, drum to drum, to swap it in. 3.25s to 3.55s would not be worth such an effort imo. Plus, you might have DS issues due to the length of the pinion set up, and the u-joint may or may not match what you have.

A 9" is easily changed, and you can find a carrier with the gears and limited slip or locker of your choice--for a price, of course. You can scour the scrappys or pay $500 + for a rebuilt one.

 

thank you for the help...i just didnt want to get over my head in the middle of changing it...this will just be a temp job till i can afford the gears for my 9inch.