slip yoke might be fine see albuq f-1s comment. How long is the yoke? You need about 2" past the seal inside the trans throughout the motion of the rear axle.

In other news... you MIGHT want a 1330 x 1350 conversion U-joint. I have the same type in the rear of my mustang. The 1350 is 1 3/16" and the 1330 is 1 1/16"

You can easily overtighten the U-bolts. 30 ft lbs is about all they should have. Getting this right is serious business... last thing you want is an axle letting loose at highway speed.

 

I would get a longer driveshaft, bushing engaged or not. Do it once and do it right. If you have a welder and a grinder it is not hard to shorten a driveshaft if you get another one that is too long, I have pics of the shaft I made for my 47 caddy and I have always done it the same way. Low buck and works fine at 80MPH, no vibrations.

 

Well bushing engaged is doing it right. A lot of oem vehicles have 2-3 inches of the yoke exposed.

 

The only downside of having the yoke further out is it will wear out the tailshaft bushing a little faster, might vibrate a little more.

 

Yeah, Ryan, I got the 1330x1350 in there after much ado. Seems to fit nicely. I guess its off to the drive line shop tomorrow to see about a new DS. It's only (more) money.

 

Typically at ride height the driveshaft shops recommend approx. 1" of exposed trans yoke, free travel, so it depends on how long your tailshaft sticks out of the trans on whether that is to much or not, And like Ross said you want to be completely through the tailshaft bushing.

And just for info 30 ft/lbs is to much torque for that u-joint u-bolt. Here is a good chart.


Randy's Driveshaft Service - Torque Specifications

 

You might want to wait until the truck is pretty much all together so all the weight is on the suspension. The required drive shaft length could change.

 

Inland Empire Driveline Service :: Driveshafts :: Ordering Driveshafts (One Piece Driveshaft)

Mine had been ordered here and this is how they wanted it measured.

 

Yep 24 is ok and 30 is a disaster. Lol. 30 is fine.

 

It's really not OK, the chart shows 13 - 18 ft-lbs for a 1330. Excess torque/clamping force may distort the cup and prevent the rollers from functioning. The chart agrees closely with recommended torques for 5/16"-24 Grade 5 bolts.

 

The length will change with a leaf spring suspension, the rear will move away from the trans when the suspension goes down. Use ratchet straps to compress the rear suspension to get the true driveshaft length needed. I find the happy spot where the driveshaft is short enough to remove with the suspension unloaded (as if on a two post lift) for future maintenance and long enough to have minimal slop in the front yoke. It can be done differently but that way has worked for me.

I dont have pics of when I did it in my truck but here is a pic of when I did it with my caddy. With the truck I didnt have a factory crossmember so I just layed a piece of steel tube across the frame to hook the straps to. No way would I run with more than 2" of exposed yoke even with the yoke all the way in the bushing, but that is just my opinion.



Here is the spacing in the truck I am building now, output shaft is about half way inside that rubber dust seal, so there is about 1" open yoke with the suspension unloaded. When the suspension is compressed the driveshaft moves away from the trans and there is about 2" exposed (going on memory, not at home now). I used a 6" long yoke from the T56 donor car.

 

I'll be careful and torque them properly. Seems like there's very little room for a torque wrench in there tho. I'll have a closer look. I think I'll use my old drive shaft for now just for mocking up and testing things, but once the weight is on the truck I'll get a new one made and swap it out. Looks like a pretty easy job. Thanks for all your help on this fellas! I would have screwed this up entirely (along with pretty much everything else on this truck without help from this forum!

Cheers! t

 

missing the key piece of info, that the U-bolt end is 1350, not 1330 and the correct torque is 24 ftlbs.

Otherwise... agree.... I put 30 out there as a general guideline not to exceed... as it was mentioned in the thread about tightening down a 1350 yoke to a 1330 u-joint until no gap was visible... had me concerned.

 

It was discussed that he might want to convert to a 1350 if he bought a new yoke, but AFAIK he still has the Ford 1330. Last I saw anyway.

 

Actaully, if he is using the 1-4635HD as stated in the quote above he is has a 1310 with one set of large caps and one small. U-joint, 1310 w/1.125 cups one end and 1.062 other side = 1-4635HD or 5-1201X

Modern Driveline, Inc. - driveshaft