I have a 2001 F350 Super Duty Power Stroke, and I'm trying to figure out what axle ratio I have. The certification label (door sticker) has code 41. I looked in the Tech folder in this forum, and there are two axle code charts. The first one is in an entry that decodes the entire label, and it says:

41 — 3.73 non-limited slip, F-350 (single rear wheels)

Then there's another chart down lower that only lists axle codes, and has less of them. It says

41- 4.10

Which do I believe? Or is the second one for some other set of codes, not the ones on the door sticker?

 

My 2005 specification book (factory) say 41 is 3.37 limited slip and 4N is 4.10 might be the same for your year.

 

If you're looking at the door sticker, use these codes:

AXLE CODES:

37- 3.73

3L- 3.73 LS

41- 4.10

4N- 4.10 LS

43- 4.30

4L- 4.30 LS

48- 4.88

8L- 4.88 LS

53- 5.38

5L- 5.38 LS

 

I bought my truck used and the driver door had been replaced due to an accident. Can I get my axle ratio from the VIN or from Ford? I guess if I have to I could jack 'er up and rotate the rear tire and figure it out.....

 

Depends on the year which you didn't give.

 

Hello Paul Heitzman and welcome to FTE.

Look in the TECH FOLDER. The information for decoding your VIN, door sticker and axle tag are all there, along with some other good stuff.

 

Look at the tag on the rear diff if its there.. Under a bolt.

 

I was lucky enough to find a tag on the axle. It has both a 73 on it a 10.5 for the axle diameter and a S 409 or something like that. So I do have some info to go on. It is a standard cab 4x4 with a 137wb

 

It has 3:73 gears and prob open diff unless you see an L on there somewhere.

 

Thank you so much. I think the first "3" of 3.73 is near or under the bolt that holds the tag on. I am very happy and I think this is probably the best compromise gear ratio for me.

 

The YEAR and MODEL are what is needed to do an axle code look up.

 

I’m looking at purchasing a 2000, F650, with the 5.9 Cummins. Top speed is 62mph at 2500 rpm. How would be the best way to increase top speed to the 70-75 mph.

 

Thats pretty much a standard speed. Or it was back when I drove trucks. Brother in laws company he drivers for has all their trucks set for 62. Most of the big tires only rated for 75. No sense trying to drive on the edge with today's traffic. JMO