Drive Shaft install question

[Jamminjohn]

I tried installing the drive shaft this weekend and I was unsuccessful.

This is a 72 K5 4x4 and it seems like its a couple inches to long?
Is there something I am doing wrong?
The motor and trans are installed in truck now.
Do I need to loosen the motor mounts and move the motor/trans forward a little?

This drive shaft did come out of this truck, I wasn't the one to take it out tho.



thanks

[cleszkie]

If the driveshaft is too long when the truck is on the ground, you have a problem. The driveshaft needs to be shortened. If the truck is on a lift, or the rear end is allowed to fully sag, the rear end will rotate towards the transfer case a bit and effectively shorten the distance between the axle yoke and t-case output yoke. This is still a problem because if you get that driveshaft in and you ever end up with the rear in full sag, the driveshaft will be in compression and pushing on the transfer case and axle yokes. I have seen transfer cases damaged in this way.

Did you by any chance do an axle swap? A larger axle will have a longer pinion snout and will require a shorter driveshaft.

[Moreyel]

Could the tail shaft of the tranny be different?

[Jdubs71]

Did you change the set up? Tranny and t case or maybe axles?

[72freak]

As long as all of the running gear is the same and mounted in the same location it should fit. Are you having trouble getting it up in the transfer case? Post a picture of how far it is going in.

[Jamminjohn]

Here are the pics!

[jeffro308]

Is it equipped with a carrier bearing?

[Jamminjohn]

Originally Posted by jeffro308

Is it equipped with a carrier bearing?

I'm sorry, I don't know what that is

[72freak]

Originally Posted by Jamminjohn

I'm sorry, I don't know what that is

Is it a 2 piece drive shaft? The carrier bearing is the mounted point between the 2 parts of the drive shaft.

[Jamminjohn]

It's a 1 piece

[jeffro308]

If you ran out of slip in your slip-yoke you might have too much grease at the end of the splines. None of the pictures shows how much you have left on the splines. I'd pull the slip yoke off and remove the excessive grease. Be sure to line it up right going back together and grease it when your done. Just a suggestion without having seen it.

[Jamminjohn]

Can you tell me if this is the slip yoke and do I need to loosen that bolt to get it out?

[jeffro308]

Originally Posted by Jamminjohn

Can you tell me if this is the slip yoke and do I need to loosen that bolt to get it out?

That's a fixed yoke. You must have a slip yoke on the driveshaft. That's the one I'm talking about.

[Jamminjohn]

Here is the drive shaft and it opens up like a shock.
The pic with the arrow: Is this side the slip yoke?

Do I have the right drive shaft?

PO gave me 2 drive shafts.

[jeffro308]

Originally Posted by Jamminjohn

Here is the drive shaft and it opens up like a shock.
The pic with the arrow: Is this side the slip yoke?

Do I have the right drive shaft?

PO gave me 2 drive shafts.

The arrow is pointed at the slip yoke. It looks like it's using all the travel so my grease build up theory is incorrect. I'd say it's too long by an inch or two. If you were able to force it in you might damage some stuff if it slams to the bottom of the travel while driving. You could have a driveshaft shop take 2 inches off for probably a hundred dollars. Was anything modified since that driveshaft was removed? Was it like that when you bought it? This is a strange thing.

Oh, the bottom picture is a front driveshaft.

[Jamminjohn]

I bought it this way, Is it possible that the motor is mounted to far back?
It sure seems like it to me, But I have no idea.

[jeffro308]

Originally Posted by Jamminjohn

I bought it this way, Is it possible that the motor is mounted to far back?
It sure seems like it to me, But I have no idea.

If your distributor will go in I'd say the engine is probably in the right place. My 72 blazer has a v8 and it's tight. The previous owner may have made some changes. If you bought a disassembled project you may run into some issues with fitment.

Those rear springs look fairly new. Is it possible that the rear axle has been shifted forward a little? Is the locator spring centered in the spring? Could the springs be backwards?

I'd recommend that you join a 4 wheel drive club or something and befriend some people there locally with some more extensive general mechanical knowledge.

[jeffro308]

Here's a picture of some typical drive shafts at

http://www.dennysdriveshaft.com/c4_4x4_driveshafts.html .

The slip-yokes are the shiny bits on the left of the shafts.

[Moreyel]

It's not far off at all. Looks to me like Jeffro is right. The slip yoke only needs to go about 1/2" in. Since that's the fixed end, you'll see where the other end is splined so the driveshaft can shorten and lengthen depending on terrain, driving conditions, etc. you wouldn't be able to do anything with a fixed driveshaft, short of driving straight down a level road.

[BKSS67]

You have round U Bolts and you should have square "U" bolts on the rear axle.

It looks like the PO tried to compensate for the mismatch with some type of insert on top of the leaf spring pack.

[Chulisohombre]

Something aint right there. Is it a lifted truck? If you tried to put the shaft in like it is it won't fit. You have to push the end in first so the end that moves is in as far as it goes and then pull it out as needed to fit the yoke. My 4 wheel drive has round u bolts but sideways and hold the axle tube itself and clamps from the top of the spring. Axle looks correct. Is it centered in the wheelwell?

[Jdubs71]

Any chance the 52" rear springs were swapped out for longer ones? That would likely offset the rear axle, but would be noticeable if the body is mounted to the frame. FYI your rear leaf spring u bolts should be the square type when mounted from the top to bottom like that. Those ones would mount around the axle tube like chulisohombre said. I wouldn't take any chances when it comes to the drive train. I don't think the u bolts Would suck down as tight in that position. The piece sitting on top of the spring pack, and the saddle around the axle tube is correct with square bolts. If you keep the round u bolts you will need a plate that goes on top of the spring plate and run the u bolts up. If you go that route i may have a set of spring plates. Let me know.

[Chulisohombre]

Unless that top mount on top of the spring is rounded like the spring it can put off if their is too much torque or the ubolts loosen up. Looks like the newer setup from newer blazers. But would require square ubolts. I don't like this setup just because the ubolts can catch on things as you drive over them. But I take mine off road which makes a big difference in the rocks.

[jeffro308]

It looks like you have some research to do. The previous posters have good points. I can't add anything absent the ability to talk with my hands.

[Chulisohombre]

If those springs are lift springs like they look like they are, they can be in backwards and there is a difference of about two inches where the center pin is on the spring to love the axle Back two inches. Check that as well. The slip yoke is definitely All the way in in the pic you posted. It may be possible you have a shortbes driveshaft there. Looks exact To the blazer but a few inches longer. You need to get that one cut or a new One made to center on the slip yoke between open and closed. The other one in the last pic with the cv is your front shaft.