What size number is our rear and front diffs??(2004 5.4 4x4 models)---9.75 or 8.8 ???and how i can make it sure if i go and look under the truck where to look??

 

The front differential is an 8.8, the rear is 9.75. You can tell this by looking on the toe tag on the differential, held on by a rear cover bolt. On the tag, it'll read the plant build number, something like "V****", it'll have "975" on it indicating the 9.75" axle, and it'll have the gear ratio and whether it's a limited slip or not. Gear ratio is shown as something like "3L73" indicating a limited slip 3.73 gear, or just the gear number, like "373," for an open 3.73 differential.

 

Thanks Quintin that was very helpfull because i thought both front and rear's were 9.75 and did not know to check it so i ordered 4.56 gears and now i have to cancel it..