Drive Shaft install question
 

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

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

Could the tail shaft of the tranny be different?

Re: Drive Shaft install question
 

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

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

Here are the pics!

Re: Drive Shaft install question
 

Is it equipped with a carrier bearing?

Re: Drive Shaft install question
 

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

Re: Drive Shaft install question
 

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

Re: Drive Shaft install question
 

It's a 1 piece

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

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

Re: Drive Shaft install question
 

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

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

I had to take the cap off of the rotor for it to fit.

Re: Drive Shaft install question
 

Can you post a picture of your rear spring setup?

Re: Drive Shaft install question
 

Here are the pics.

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

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?

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

I am a little suspicious. The first driveshaft picture shows the leaf springs without u bolts. Jamminjohn, are you reassembling a basket case that someone else took apart? If so, who knows what drive shaft that is. It looks like it'll work fine with an 1-1/2" to 2" taken out.

Re: Drive Shaft install question
 

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.

Re: Drive Shaft install question
 

I am afraid so, It was a trade gone bad.

I went to pick up the parts for the blazer and those were the 2 drive shafts that were there. I can not confirm that they came out of the blazer(I wouldn't know why he would have them if they didn't).

The truck is lifted, I do not know what size lift. Ill have to check to see that it is center in the wheel well, My first thought would be yes.



Do I need to flip the ubolts over?

I really do feel that the motor is a little to far back, But I am not sure. I do see that there are bolt holes in the frame for the cross member to come forward 2 inches

Re: Drive Shaft install question
 

Yeah it's too far back. I believe the back holes are for strait six mounts. I must have missed that if you said it before. If that's the case the front shaft will be two inches short as well. Or will be extended to the end of the slip yoke.

Re: Drive Shaft install question
 

I went out last night to look at it and it looks like that the transmission can not move forward anymore, there are two large bolts on the side that its bolted into the transfer case. The holes are through the the side of the frame.

Ill post pics tonight when I get home

Re: Drive Shaft install question
 

If that's bolted in the right place then or has to be right. If they didn't red till the holes there or the adapter crossmember then it is sitting correct. Tomorrow ill Look and see where my engine sits in relation to those bolt holes and see if my frame has that front extra set. Measure your rear springs from the center pin to the spring eye on either side to see if they may be turned around to get a better length for the rear shaft to fit. Mine had a 2 inch offset to put the axle farther back in the wheelwell. Have you attempted to put the front in yet?

Re: Drive Shaft install question
 

Those two bolts in the side hold the drivetrain in place so it doesn't let it flex when revving the engine on hard takoffs. Otherwise on auto transmissions it can crack the case on it if its missing. It's good that it is still there.

Re: Drive Shaft install question
 

I have not attempted to put the front one in yet.
I will measure tonight when I get home. Can you tell me where "the center pin to the spring eye" is?

Re: Drive Shaft install question
 

The center pin is in the very center of the springs and is bolted through all of the leaves to hold them together. The spring eyes are the two ends that bolt to
The frame in the front and the shackle in the rear.

Re: Drive Shaft install question
 

Just read on another board that 6 cylinder and 4x4 used the same engine mount location. So your in the right location with the engine. Mine has to be the same then.

Re: Drive Shaft install question
 

Yes your engine is in the right spot for factory. I moved mine forward to those holes and had to drill out the rest as you will notice the rest are not there. There is controversy over the t-case bracket you speak of though as many hard core wheelers say that is what cracks the adapter. I have run mine without this bracket for a long time and no cracks. I run a serpentine system and electric fans and 4" lift so it was easy to move forward and OMG are things easier to work on! Now is the time if you have to adjust drive shaft lengths.

Re: Drive Shaft install question
 

I've heard it both ways as well. But if all the bushings engine trans and side are good and not wirn out it should stay pretty much still and Make the frame torque to a minimum and not let the engine twist like it does With the weaker car engine And Trans mounts. I have a 4 speed 465 trans so I wouldn't worry about it either way. I think the later 70s and 80s trans had a weaker Casting and would have to worry about it more Than our trucks. Same goes With where the later Trucks crack their frames at the steering box and Ours is thicker and doesn't happen nearly as Much. Hardcore wheeling breaks a lot Of stuff that doesn't normally have a problem under normal use. Once you start Getting Into crazy stuff it's not a matter of if but When something breaks. If I have a problem that's when I upgrade Or Change it. Three rears later is why I went 3/4 ton. Lol

Re: Drive Shaft install question
 

Sorry to steal a photo from this thread but what is the plate called on the front of the u joint where the arrow is.I have that plate spinning when the clutch is engaged and need to fix it.