Driveshafts - They're not all the same!

[Bronco638]

Nothing like thinking you're got something all lined up and ready to use only for a little research to remind you how little you really know........

The Trucks:

1981 F-100
VIN: 1FTCF10E5BUA37***
MFG: 01/81
Trans: B
Axle: 17
WB: 117

1980 F-150
VIN:F15GRGD4***
MFG: 10/79
Trans: K
Axle: 17
WB: 117

Based on the VIN and the door jamb sticker, the 1981 F-100 had a 300/6 and SROD (even tough the trans code indicates a Clark Overdrive unit?). It now has a rebuilt 302. This doesn't seem to matter with respect to the driveshaft.

Based on the Marti Report and the parts I received with the truck, the 1980 F-150 had a 351M and C6.

I have both driveshafts and both yokes. I was hoping to use the original driveshaft from the F-150 because of its condition; it's still has the factory black paint. However, based on my reading of the driveshaft data from this site, it appears as if it's too short and the yoke is not the same:



The F-100 is in the red box. The F-150 is in the blue box. Would someone be kind enough to verify my findings?

In retrospect, maybe having a driveshaft made wouldn't be a bad idea.

[Gary Lewis]

Yes, I think you have figured it out.

Ford used a wide variety of driveshafts in these trucks.  Some of that is due to the length of the transmission.  Some for other reasons I don't understand.  But your two trucks had different driveshafts.

[Bronco638]

Thanks for confirming Gary. Both driveshafts are in storage but it should be pretty simple to verify. One is almost 4" longer than the other.

They use the same u-joints though. Is there a way to convert a Ford 41 and Ford 42 u-joint number to a Moog part #? I see that the Industry Designation is 1330 and even though there are two Ford Part numbers (one of the caps is 1/16" larger, in diameter), they have the same industry designation. Huh.

Looks like there is a Moog 1330 u-joint. That was easy.....

[Gary Lewis]

Our page at Documentation/Driveline/Driveshafts has a tab labeled U-Joints.  There you will find a cross-reference from the Ford #'s to industry standard #'s.

[Bronco638]

Gary Lewis wrote

Our page at Documentation/Driveline/Driveshafts has a tab labeled U-Joints.
There you will find a cross-reference from the Ford #'s to industry standard
#'s.

Yeah, thanks, I found that page. However, the Industry Standard # doesn't seem to match or I'm not doing something right.

I checked Moog's site as well as Rock Auto. Both are showing a 354 u-joint at the trans and a 434 u-joint at the diff. (for the '81 driveshaft with 4.9 or 5.0 engine - the F-100 had a 4.9 originally then a 302). The u-joints for my Flare Side (351M/C6 - original drivetrain) are completely different (no surprise).

[Gary Lewis]

Yes, now that I look at it I find it very confusing.  The Ford diagram shows one dimension, D, for the bearing caps.  But some of the u-joints have two different cap sizes.  And there's an industry standard size of 1330 with differing dimensions.  

This page shows dimensions for a Moog 354, so maybe you can compare to that?

[ArdWrknTrk]

Ford is known for "combination" joints.  

I pointed out in another thread that if you have the cap diameters and the spans there is a handy page on the Moog website that spits out the correct number.

[Bronco638]

I may have shot myself in the foot as the old u-joints are gone. And, none of the dimensions provided by Ford (found on this site) seem to match up with the Moog data. They do confirm that the 354 is a Spicer 1330 and the 434 is a Ford 1330. Not sure how much that data point is now worth...