Bent Rear Driveshaft??

[TickDontPick]

89 XJ 4.0 AW4 NP242 D30/D35 STOCK

After breaking and replacing the u-bolt and straps on the axle side of my rear driveshaft, I have been getting vibrations at 55+ mph. I took her in to a local 4 wheelers shop, and they took a drive and said that it was a bend in the driveshaft causing the vibrations.

Now im not quite sure where to go with this. Do I get a SYE/CV so I dont have to worry about it in the future? Do I get my existing driveshaft repaired? Do I junkyard it, or do I just get a new driveshaft?

I would love to tackle this project myself, but I dont have any special tools nor any driveline experience. Should I leave this one for the experts??

Thanks in advance for any insight.

 

[Midnight Krawler]

Just go and get one from the junk yard. Put in new u-joints and your good to go. Just make sure its the same lenth.

 

[TickDontPick]

but do you need an impact wrench to do the job? I'm just worried about doing something wrong and causing more harm than good.

 

[87manche]

you need nothing more than basic hand tools.

 

[BrettM]

get one from a junkyard, unless you plan on lifting it in the near future, then you might as well get the SYE now

 

[RCP Phx]

Ive got 2,it's yours!

 

[BrettM]

Ive got 2,it's yours!

you should charge him $30... and throw in a free membership

 

[Ralph]

I'm just worried about doing something wrong and causing more harm than good.

Doing something wrong is part of the learning process. Sooner or later everyone screws up. When you do, chalk it up to experience and move on.

 

[TickDontPick]

You are right, this would be a great learning experience.

I read something in my haynes manual saying that you need to mark the driveshaft yoke with the pinion yoke and make sure the marks line up when you put it back on to preserve driveline angles and such, but I'm not really sure what they are talking about. Can i just bolt on another driveshaft and be good to go? Is there anything I need to keep in mind or look out for? I suppose I need new u-joints too?

 

[WB9YZU]

Removal:
Chock the wheels and/or apply the emergency brake .-make sure it won't roll over you-
Put the truck in neutural.
There are (4) 5/16" (or 8mm, whichever way you want to look at it) bolts holding the straps on the pinion yoke. Remove them, and set them asside along with the straps.
Look at it and get a mental picture.
You may need a screw driver to pry the u-joint from the yoke. The DS will slide forward slightly as the u-joint clears the yoke, and if you are not holding it, it will drop.
Let it down a little so it clears the yoke, and pull the drive shaft out of the transfercase.

Reinstallation:
Clean the slip yoke end of the driveshaft. Put a coating of ATF or other lubricant on the exterior of the slip yoke, and install the yoke in the transfercase.
Rotate the driveshaft so the u-joint is aligned with the yoke, and install the u-joint in the rear yoke just like your mental picture. U-joint caps should sit between two tabs that stick up from the yoke base.
Install and tighten straps.

There is no alignment, so don't bother with the marks. Balance of the drive shaft is shaft dependant and that should have been done at the factory.

 

[WB9YZU]

...

 

[carnuck]

You are right, this would be a great learning experience.

I read something in my haynes manual saying that you need to mark the driveshaft yoke with the pinion yoke and make sure the marks line up when you put it back on to preserve driveline angles and such, but I'm not really sure what they are talking about. Can i just bolt on another driveshaft and be good to go? Is there anything I need to keep in mind or look out for? I suppose I need new u-joints too?

Mr Hankie's... I mean Haynes, are not known for 100% accuracy. I rewrote the FSJ book with most of the errors edited out and more info put in, but they weren't interested in buying it. (or Children's... I mean Chiltons!)
When you take apart a fixed yoke driveshaft (one that bolts onto both ends and has a slip joint in the middle) you need to keep both halves phased correctly or vibration will occur.
It IS possible to make the front shaft out of phase (because it is that type of shaft), but the rear slip yoke and main shaft style won't matter (unless it was assembled poorly and rebalanced to make up for it)