Drive shaft length for 14 bolt FF swap

[Redfred]

I don't think there is a definitive answer to my question due to the many possible applications so I will just ask if anyone could share info from experience. I'm taking out the rear 10 bolt in my 85 K10 and swapping with a 14 bolt FF. The truck is a standard cab long bed and has a TH350 and a lift with 5 3/4" blocks in the rear.

I know the 14b has a longer pinion length so I'm assuming that my existing 1/2 ton drive shaft will be too long. I already plan to pick up a 1310/1350 u-joint but the issue of length dawned on me just recently. So is it a unanimous "no" for compatibility or has this been done without having to replace or cut down the 1/2 ton drive shaft?

 

[big dan]

I used my factory shaft with a conversion joint on my 85 k10 shortbed with a 4 inch lift. Ive read the the pinion snout is an inch or so longer on the 14b but Ive swapped 4 into 4 different k trucks without ever having to swap the driveshaft.

By the way, if your k10 shaft is factory 1985 it is not a 1310. I think the joint is called an s44 but regardless the part number for the conversion joint is 447

 

[Redfred]

447? I don't know how I missed that. Im glad you threw that in there before I ordered the 1310. I found this thread and I thought I understood until post 15. He is adamant that a 1330 doesn't work. Isnt the 447 a 1330 on the 10 bolt side?

http://coloradok5.com/forums/showthread.php?t=82988&page=2

Since you've done 4, I believe what you said so im going with the 1330/1350 but that dude in post 15 is so adamant that the S44 is it, not the 1330. So I guess there is a 1310, 1330, S44 and 1350 but searching the web, all you hear about is primarily the 1310, 1330 and 1350

 

[rebelgregory]

Factory shaft or CV? Personally, I had a CV made when I had a 10 bolt. Wouldn't work with the 14 bolt. But I used WFO Concepts spring perches and plates to move the axle back 1" and the CV worked.

 

[big dan]

the 447 joint is an s44/1350 conversion joint. I don't know that gm ever used a 1330 series joint in the 73-87 trucks.

 

[campfire]

I got luckier yet. I removed the 10-bolt from my 1984 Suburban and replaced it with a newer 14BFF from a 1997ish G3500 Express Van. When I did my swap, I found (to my surprise) that the yoke matched up. No modifications or u-joint replacement required. I took my stock driveshaft and bolted it right up. Didn't even bother removing it. Not sure what other 14BFF axles come with that yoke, but Autozone shows them using the same u-joint, so it must be somewhat common. May be worth checking into if you haven't bought your axle yet. I'll also note that the E-brake cables that match that axle (drum brakes outside the hub rather than inside) use the same cable ends as the stock Suburban axle (just longer). Overall the swap was much easier than I had expected from my reading.

I don't know of anyone else on here who has done it this way, but you can see a couple pictures of it in my Suburban thread.


Part number data copied from Autozone.com:

1984 Chevrolet Truck K10 1/2 ton Sub 4WD 6.2L Diesel 8cyl Part Number: 2-0053DG
Alternate Part Number: 231

Link 1

1997 Chevrolet Truck G3500 1 ton Van 5.7L SFI 8cyl Part Number: 2-0053DG
Alternate Part Number: 231

Link 2

I'm don't have a direct cross-reference from Autozone's website (of course ), but looking at their spec table and this chart leads me to think I have a 1350 u-joint. That doesn't sound like what others are running, but that is what the catalog says. I do wish Autozone would give cross-reference numbers directly...

 

[kennyw]

If you have a factory driveshaft with the stock axle and 5.5" lift, the driveshaft is too short since the lift moves the axle away from the tcase. The longer pinion of the 14FF will actually help fix the issue but may still be on the short side of ideal.

1310, 1330, and 1350 are Spicer corporation specs for u-joints, S44 is a different spec all together from another company (possibly metric?).

 

[Redfred]

If you have a factory driveshaft with the stock axle and 5.5" lift, the driveshaft is too short since the lift moves the axle away from the tcase. The longer pinion of the 14FF will actually help fix the issue but may still be on the short side of ideal.

1310, 1330, and 1350 are Spicer corporation specs for u-joints, S44 is a different spec all together from another company (possibly metric?).

To be honest, I'm assuming it's the stock drive shaft but it could have been replaced. If there's one thing I've learned from owning a 30 year old 4x4 it's to never assume any part of it had never been changed/altered. Long story.

Guess we'll see once I swap them out. I feel optimistic since Big Dan was able to use the existing shaft 4 out of 4 times. At least you guys straightened me out on the u-joint thing.