Had a great time this weekend swapping out my front differential. Now I did this because I broke the spider gears and found the Dana 30 for cheap do now I have spare parts. I took off the front drive shaft and noticed a lot less vibration as I drove. Once I hooked it back up I got it all back again. Now, the ujoint is new in the yoke but the shaft it's self In the middle where it extended tends to have a little wiggle which I think is the problem. How to fix this??? Aftermarket shaft ??

 

If there's a salvage yard near you, just grab a spare shaft for cheap.

 

Agreed, then youll have a trail spare if need be in a pinch.

I just grabbed a boneyard d30 shaft and have it sitting on the counter. There is no play in the extendable yoke at all so that seems like it would be the problem with your vibes. If you are in a winter climate and need 4x before you can get a shaft there is something to try that may help rid you of some if the vibes. Ill probly get flamed for this but oh well. Ive had good luck just simply removing the shaft and re installing it 1/2 rotated. Idk why and idc why but on two different occasions in different vehicles this has worked for me.

Pic is for outlaw
See i didnt guess this time. Lols

 

The odd part is that this is my 2ns different drive shaft I got and at first it didn't have any play in it. Within time, it has it now..


Not sure if this has any affect but im on a 6.5" lift on 35s, 1.5" TC drop

 

Adjustable upper control arms or stock?

 

adjustable upper and lower

 

Your problem is the front pinion angle. Going through this now. If the pinion angle isn't almost dead in line with the driveshaft (pointed straight up at the shaft during ride height) then the pinion u joint has to work and in return you get that wiggle in the slip joint of the driveshaft and vibes occur. Just did a 2000 Cherokee 4.5" lift and did new lower arms but stock uppers. Well the pinion was pushed down and now my dshaft vibrates bad. Changed it with a boneyard one with good I joints and its worse. The new shaft has 0 wiggle in the slip joint. My fix is I'm gonna purchase upper control arms and fix the pinion angle

 

Ok in the morning im going to snap some photos if it

 

Well i forgot to ask about long arms or not but here is the control arm measurements i used for 6.5" with the RC drop brackets.
the arms are damn near level with the ground and the shaft is straight.


I did add 1/8" to the lower and 1/4" to the upper arm measurement because my rear is a heavy 7" over stock.
Its all in the pinion angle like the other poster said, you want the shaft as straight as possible or that cordon joint will wallow out the yoke and loosen it all up.

 

The "rotating" of the shaft worked due to "phasing" of the U-joint. As a U-joint wears, it creates a wear pattern from riding on the yoke, by switching this "pattern" around it can create a vibration or remove one. I know it sounds weird but its the best I can explain it without physically showing you. Lol

 

So here is my front shaft angle. Now that you mentioned it I can see it's off

 

How can I better the angle? By extending the lower control arms to push forward?

 

Yup
But you may need to shorten the uppers some also to keep the tires centered in the wheel well. Start with the lowers to get the pinion straight then take a look at where the tire sits in the wheel well.
When your done get an alignment to have any caster or camber issues fixed so it'll drive right.

 

So what's the best option if spines on front slip joint are worn?

 

What's the easiest way to adjust the upper arms?do I jack up the front and then unbolt it from the axle?