My truck is an '81 F250 4WD. It has the twin traction beam front axle(s), a Dana unit. I need to know how to identify which axle it is, Dana 35 or Dana 40. The carrier casting has some letters (A and a B, I think) and numbers (023) cast in.
The truck was built by a cousin from a number of different vehicles, and there's no way of knowing what vehicle the TTB came from, so I'm stuck with looking at the unit itself.

 

There are only 3 ttbs. The dana 44, the dana 44HD, and the dana 50. Since you have a f250 with front leaf springs, you will have a dana 44hd or a dana 50. If you know someone with a f150, look at their hubs. If your 4x4 hubs are the same size as the f150, then you have the dana 44HD. If you have larger diameter 4x4 hubs, then you have the dana 50. Your truck would have come from the factory with the dana 44HD.

 

Well, that's simple enough. No f150 handy, but a friend has an 84 f250 with a 6.9 and I know it's a HD. I'll compare it.
btw, If you know a Dean Caldwell there in Staunton, tell him Deke sez hi. Statlers forever.

 

Typically, if it's a regular cab it's the D44HD. Extended cabs got the D50. The 6.9 in a regular cab would get the D44HD.

Here's a visual ID.

 

My hub measures 3 inches. I suspect it's the 44HD.

 

I believe the D50 third members have the number 50 cast into the bottom as well.

 

look at the sticker in your drivers side door jamb, I think the D44 is a 3800 GVRW rating, the 50 is 5000 something I think..

 

Mine does.

 

Is it an 8 lug hub? If not surely somebody didn't swap in a D44. The rear is either the D60 or the Sterling 10.25 and both of those are 8 lug units. So surely you have the same lug nut count on the front as the rear?

 

The D44HD has 8-lug wheelhubs, with 9/16 studs. It uses the same 19-spline lockouts as any other D44. I think most of the parts are D44 parts, but the hubs are definitely 8-lug.

 

You are correct, I believe Autozone says the 44hd is 3850 and the 50 is 4600lbs.

 

My 86 F250 Supercab with a D50 has a front axle weight of 3,920lb. I'll have to look at what my 87 F250 RC with the D44 is rated at.

 

I am not sure exactly how that works, but it may be the rated load in that truck. In other words, possibly a regular cab truck would have higher number since it's lighter. They may have subtracted the heavier weight of a extended cab truck, so that lowers the axle's capacity.

 

I wonder if it has anything to do with the spring package on the front?

 

Springs should not change the axle weight rating. They would change how much it sagged under load, but stronger springs does not raise the axle's ability to carry a load.