not sure what i have? my truck is an 06 screw xlt 4x4 with the 9.75 rear end.
any suggestions?

 

Should be a tag on the rear end cover and it should have the gear size stamped on the tag. One tag will have the gear size on it and the other one will have the type of gear lube you should use.

 

Take a look at the axle code on the ID plate, inside the driver's door. Then do a google search for 2006 Ford truck Axle codes. One of the forums had a complete list of codes, listing both open and LS. Another option is to jack the truck up, mark a tire and the drive shaft. Then spin the tire one time and see how many turns the shaft spins. Example 3 and a half would be a 3.55, or 3 and a qrtr would be 3.73s.

 

thanks appreciate thge quick response from both of you will check it out tomorrow, thannks, william