I have noticed that my rear axle has a 12 bolt diff cover. everything i can find tells me that that means i have a 10.25 rear end is that goos bad or indifferent?

 

Depends what truck its in. If its a 97/98 F250LD or 99+ F150 7700lb then IMO no its not a real great axle. Those 2 trucks are the same, just different badges. The problem with those is that they use 7 lug axles which limits you on aftermarket stuff. Now if its an older F250/350 with the 10.25 then its a better axle as its an 8 lug pattern. There were 2 configurations in those 10.25s a full floater and a semi floater. The full floater is the better as its a heavier duty axle.

 

You have the 9.75 if it's an F150 with the 5.4 and does NOT have the 7700 payload option.

 

I second what Mitch said.

The 10.25 semi floater is a great axle. It is rated, according to Ford, at 5300lbs. Not too shabby. It is VERY heavy duty for an F150.

 

the truck is a 2002 f150 4x4 with a 5.4L the gvw is 6900lbs
its a 5 lug rear end 12 bolt diff cover. how do i tell if its a floater?
and as i said the axel code is 27 and according to a link i found on another thread said that code means its a 10.25 axle

 

K, last time. You don't have a 10.25, trust me. You have a 9.75 rear axle. The 9.75 had the 12 bolt diff cover and that was the axle that was put behind the 5.4L in the non 7700lb package (WHICH YOU DON'T HAVE). My guess is that you looked at the wrong code, you don't have a 10.25 axle.

 

The easiest way to tell if an axle is a full floater is to look at the hubs. If the hub is connected to the studs/rotor directly, it's semi-floating. If the hub protrudes from the wheel a bit, and has bolts on the end of the actual hub, it's a full floater.

A semi-floating axle supports the torque of the engine, along with the weight of the vehicle. A full floating supports the torque of the engine only, while the hub/rotor assembly supports the weight of the vehicle.

-Flea