Why won't it go back on?

[zoomer]

I pulled my drive line out of my 71 longbed. Replaced the Mid shaft carrier bearing and all 3 ujoints while I was at it.
Transmission drive shaft when in without problem... But I can get the rear shaft to go on the splines. I've tried all 100 different spline combonations. I have taken off the cap and the retainer.. I lined the ujoints up it will go on in 1 spot about 1/4 of an inche with the joints lined and then it stops! WTH??

[BobbyFord]

Not sure exactly what you are talking about. First of all, when I mess with a two piece driveshaft, I mark all sections of the driveshaft with a metal marker so that the assembly goes back together exactly as it came apart. Driveshafts are balanced and must go back together exactly as they came apart to retain the balance. With the tires chocked and the e-brake on you should be able to put the trans in neutral and install the driveshaft. make sure to grease the slip-joint.

[zoomer]

Not sure exactly what you are talking about. First of all, when I mess with a two piece driveshaft, I mark all sections of the driveshaft with a metal marker so that the assembly goes back together exactly as it came apart. Driveshafts are balanced and must go back together exactly as they came apart to retain the balance. With the tires chocked and the e-brake on you should be able to put the trans in neutral and install the driveshaft. make sure to grease the slip-joint.

well I dropped the ball on marking it.
But it will not slip back on..

[bigmerc2003]

Did you use the same size u-joints? maybe the new ones have a larger cap?

[ScreaminZ]

Did you use the same size u-joints? maybe the new ones have a larger cap?

I believe he's referring to the splines themselves not slipping together. That would have nothing to do with the u-joints.

[fordman]

is it just dirt and grease on the inside of the female splines. maybe it being floppy on you and not going on straight. maybe its trying to start at an angle. hopefully the male splines didnt get mushroomed whiel the carrier bearing was being replaced.

[Hawkrod]

The fact that you did not mark the shaft may end up coming back to haunt you but it also indicates you may not have much experience with these. If that is true, you may not be aware that the rear shaft front yoke has a removable front cap with a dust seal inside. Unscrew the cap and instal the cap and shield on the splines and then install the rest of the yoke on the splines. I will wager that the dust shield has turned and you are not actually hitting the splines. Now the important part, You need to make sure you index the shaft. There are actually only two ways it can fit because you have to properly align the U joints or you will have massive failure. Put it together with it clocked properly and then drive it. If you have a vibration then take it off and turn it over 180 degrees and try it again. To properly phase a shaft set you have to imagine it is two seperate shafts. If you look at the rear half, you will see that the yokes welded to the ends have the openings for the bearings lined up. Basically what you now have to do is put the slip yoke on the front shaft as if it were aligned in the same fashion so that the opening on the slip yoke matches the opening on the front of the shaft. This basically means that the front yoke at the trans will be 90 degrees to the yoke at the back where it attaches to the rear end. Hope this makes sense, Hawkrod

[zoomer]

I took off the dust cap, and I've aligned the yokes. Not sure what's going on.

[zoomer]

I took off the dust cap, and I've aligned the yokes. Not sure what's going on.

[mlheppl]

By chance, when you were replacing the ujoints, did you clamp the inner spline part of the slip yolk in a vice? If so, you could have damaged the internal splines so that they will not allow the yolk to slip onto the transmission splines. Just a thought. It's hard to troubleshoot something like this without seeing what's going on.

[Hawkrod]

That is a very good point, any pressure to the yoke can cause deformation. Even a little can make it impossible to put back together. Hawkrod

[zoomer]

By chance, when you were replacing the ujoints, did you clamp the inner spline part of the slip yolk in a vice? If so, you could have damaged the internal splines so that they will not allow the yolk to slip onto the transmission splines. Just a thought. It's hard to troubleshoot something like this without seeing what's going on.

It's a good thought, but with my old shotty vice I doubt I could put that much pressure on it. I could hardly get it to squeeze the caps in.
Harbor freight you know? LOL

[mlheppl]

You'd be surprised at how little pressure it takes to pinch the yoke out of round. One way to find out for sure is to take your driveline to either a tranny shop or junk yard and try to slip your drivline onto another tranny or tranny output shaft. If it slips on, your're good and you may be just having a problem with stabbing it at a bad angle or something. If it won't slip onto another tranny, then your yoke is likely ovaled a little.

[zoomer]

Does anyone have a coupling shaft for a 71? If so how much?

[fordman]

how long and what transmission? where did you make the measurements from? slip on or bolt on yoke?