Installing 4:10's

Extended Power · Jul 17, 2015

Anyone have a list of all the parts, pieces, and procedures for swapping out a set of 3:73's to 4:10's in a 2003 F350?

The last time I took it in to have this done, the shop kept the truck all day, and said I didn't have the right parts...they ended up puttin the 3:73's back in...

I ordered parts from The Gear Center, and had a kit for the 10.25" rear end...was told that you use this kit for the 10.5" rear when you are installing the 4:10's.

Extended Power · Jul 17, 2015

Sorry...I had ordered the parts from Randy's ring and pinion.

suprdzlduty · Jul 18, 2015

Don't have a list but when I ordered my 4:10's from Randy's I got the install kit with them...had everything needed and then some. Maybe the shop didn't really want to do the job? Setting up new gears, correctly, isn't exactly the easiest job ever...as I'm sure you know.

Extended Power · Jul 18, 2015

suprdzlduty said:
Don't have a list but when I ordered my 4:10's from Randy's I got the install kit with them...had everything needed and then some. Maybe the shop didn't really want to do the job? Setting up new gears, correctly, isn't exactly the easiest job ever...as I'm sure you know.

Yeah, looking around I see that they recommend the Master Overhaul Kit for a 10.25", and that will have everything to install the 4:10's into the 10.5" rear.

william_ace · Jul 20, 2015

I'm pretty sure what you just stated is correct. I am contemplating going 4.30s in mine soon so if you could follow up with the end result, I would surely appreciate it.

Luke@MillerPerformance · Jul 20, 2015

Extended Power said:
Yeah, looking around I see that they recommend the Master Overhaul Kit for a 10.25", and that will have everything to install the 4:10's into the 10.5" rear.

10.25 install kit is what you need. You also may need a different carrier.

Extended Power · Jul 20, 2015

Solved the front diff problem....
Pickin up a complete diff tomorrow that already has 4:10's in it.

The carrier that's in there should be good for 4:10's and down. (3:73, 3:55, etc)
There is a different carrier for 4:10's and up. (4:56, 4:88, etc)

Gonna save up for a Tru-Trac for the front diff, and go right through the whole differential before it goes in.

Extended Power · Jul 22, 2015

Well...turns out the guy was wrong on the gear ratio...but only after unloading it, moving it into its "spot", and him driving away...
Wiping the sweat from my brow, I thought I'd give it another look over, and discovered the sticker that had "3:73" on it...I called ford with all the part numbers, and sure enough...it's a 3:73 ratio.

Good thing is, I now know I'm just going to do a gear swap, not the entire unit.
That sum bish was frickin heavy!:shocked: