F150 rear axle gear change

[TecheMan]

I have a 1998 F150 4.6 V8 with 3.55 gears. Been doing some research trying to find out if I have 8.8 axles or 9.75. And also what parts do I need to complete the job?
Thanks TecheMan

[spadoctor]

If its 4WD you need to do the front diff also

[time2roll]

Any good transmission or differential shop will know what you need.
My guess is 10 bolt 8.8 is behind the 4.6L.

http://www.ringpinion.com/Default.aspx

[MitchF150]

Sport45 wrote:
What's the axle code on your door sticker?

I think the axle code will only give you the gear ratio. Not the physical size of the rear end..

If a regular F150, the 4.2 and 4.6 equipped trucks came with the 8.8. 5.4's got the 9.75.

Count the number of bolts that hold the cover.. 10, it's the 8.8. 12, it's the 9.75.

Also, the 8.8 is basically a round cover. 9.75 is kinda oblong..

If you have a 7 lug of that era, it's a 10.25 semi float rear end and has 12 bolts holding the cover on too.

If the tags are still on one of the bolts on the cover, it'll show "8 8" or "9 75" stamped on the tag.

Mitch

[TurnThePage]

Ooops! Double post!

[TurnThePage]

The standard 4.6L F150 had the 8.8" diff. But you mentioned in an earlier post that yours is the heavy duty model, which I think has the 7 lug wheels. I don't know, but I would bet a lot it's not an 8.8.

[Sport45]

What's the axle code on your door sticker?