3.73

[frankenwrench]

Just ran across a sweet deal on a solid front axle. Everything I need is there to swap over to my 91 f250 7.3 IDI 2wd from a 1990 f350 cc dually 7.3 idi. Here's the deal, I have swapped the 10.25 my truck came stock with for a 2001 srw with the 3.73s. the front end I will be getting has 4.10s in it and I want them to match and have found nothing for it that will fit the application. I assume since the doner is a cc dually that it is cab and chassis and I will have to move the spring perches on the front axle housing. But still want front and rear ratios to match. Any suggestions are welcome and any pointers as well, except putting 4.10 back in the rear. Unacceptable...... Love my 3.73s too much now.

 

[frankenwrench]

Also, how do I know if the gear is reverse cut or not?

 

[Garbage_Mechan]

All the Ford D60 fronts Ive seen are reverse cut. Check out Randy’s Ring and Pinion for the gears. 373 is probably the most common in F250 and F350 are.
C&C trucks are narrow in the rear but the front frame and suspension is unchanged. So that is the same width 99-04.

 

[Garbage_Mechan]

The spring perch width is not easily changed since one is cast as part of the center section. The easiest way to put 99-04 front axle under 80-97 is with a SKY off-road or PMF shackle reverse kit and a new pair of 2000-2004 front springs. The offset to accommodate the different width is built into the brackets and shackles. A very slight lift (leveling) and a much improved ride result.

 

[Garbage_Mechan]

I just noticed you said 1990 axle. Does your front and rear lug bolt pattern match now? If not the 99 up axle is a better choice.

 

[frankenwrench]

The doner is a 1990. My front and rear lug pattern already doesn't match. Not at all worried about that. Using wat I have available as well. So the fronts from regular pu and the cab and chassis are the same in this bricknose era? I will check out randys ring and pinion and see what they have. Guess I need to find the old tape measure and my mud boots and go check that out. Thanks man!

 

[Garbage_Mechan]

You have a little fab work to do to the 2wd frame. You can just put a tube through the frame for poly bushings ( check out Ruff Stuff Fab) and eliminate a lot of fab and the worthless A shaped shackles. Was all set to do that before deciding to go with RSK and 99 up springs.