I've read a couple/few posts from people with F350s that are "supposed" to have 37-spline axle shafts in the rear, but don't.

I know what the "book" says about it, that F350s have larger diameter and more splines than F250s.

Has anyone confirmed they indeed have 37-spline shafts? The only posts I've seen where people have pulled them, have 35-spline shafts.

 

I would like to know the definitive anwser as well. There are potential implications for me when I install a lift kit and new gears.

 

The guys at randy's ring and pinion state that all the Sterling 10.5's are 35 spline - I think the confusion comes from the improper alignment of the columns in the "book."

The 37 spline should be the DRW Dana 80 I believe.

 

I do believe you are right. Only the duallys have the Dana 80.

 

Well, one poster confirmed he had 37-spline shafts, in another thread; however, it was a 4.30 ratio (V10 truck). I know, per the book, the 4.30 ratio trucks have a Super60 front end (V10 trucks), so another part of my question, or reason for my question, is I'm wondering if the V10 trucks with 4.30 have a Super60 front axle and 37-spline rear axles; whereas diesels and gas trucks with 4.10 down ratios might have the 35-spline rears. I'm really hoping that more people with 37-spline rears chime in, so I get get a better idea of why some have one and others have the other. There is only one poster that I've read of with a 37-spline rear, all others had the 35-spline, and I'm trying to figure out why. It's actually got me wondering if I should pull my own rear shafts, but I have an F250, so I should have the 35-spline shafts (should be no reason to pull the rear shafts).

So, it appears it's not a mis-alignment of the book, or just Dana 80s...

 

Super60 is the wider axle on the F-450/550 in 05+ trucks

I thought it was the SRW trucks with the 11,400 GVWR had the 37 spline 10.5".

It's easy to pull the shaft to measure and count the splines. If you have the stock wheels don't even have to take the wheels off, just remove the center cap, remove the bolts that hold the axle shaft to the hub and pull it out.
Of course you'd want to chock the wheels and have the e-brake set.

 

Well, see there again, the "book" (builder's guide) states the SRW V10 with 4.30 has a Super60.

 

I have a 2006 F-350 and I pulled the axle and they were 35 spline! The 37 spline is in the Dana 80.

 

11,400lb GVWR?

 

I would love to know this also, I nhave heard they are 37 spline, but when I also contacted randy's they told me different.??? I would love it if they where 35 spline so I can install a trutrac. My gvwr is 11,200....

 

So, Randy's told you they are 37-spline?

 

If you want to swap in a Trutrac, why not just pull a shaft and see?


Quick and easy to do. If I was looking for an aftermarket LSD or Locker that's what I would do to be sure.

 

no they said it only comes in a 35 spline and they weren't aware the 350's had 37 spline axles? I have always heard on a couple of forums that the 350's have 37 spline axles and the 250's have 35 spline axles.....im almost to the point that im gonna pull the axle to check, I never knew it would come out that easy without pulling the diff.cover. But its a bit to chilly out here in beantown for me to want to do it, I will be haveing to do something soon because my rearend is still making noise( I think its pinion bearings but not sure) and I dont want to rebuild/replace a factory diff If I dont have to , I would rather upgrade to a truetrac as I dont need/want a locker.

 

Unless you have a Dana 80 in the 11,200 GVW, then you would have a 35 spline 10.5 sterling. Just pull the axle, it is real simple. Take off the 8 bolts from the axle cover and the axle slides right out. You do not need to remove the housing cover. FYI: make sure you do this on level ground. Once you release the axle the truck will MOVE! Use the emergency brake and chock the tires.

 

The thread is moving a bit, toward a different topic. The OP, me, was wondering if anyone pulled an axle to find a 37-spline. I've read a post and one person has gotten a 37-spline, so, I'm wondering who else has, so I can form a pattern (who gets them and who doesn't).

The Dana 80 may well have 37-spline shafts, but a person with a SRW F350 has stated he did too, so it can't be just the dually trucks or the Dana 80 differentials.

So, back to the original question: Anyone with a 2005+ F350 have 37-spline shafts? Or, anyone know why a 2005+ V10 with 4.30 SRW truck has 37-spline shafts?