Driveshaft questions/problems

Tech11

Tech11

Well-Known Member
Joined
Dec 7, 2007
Location
Greensboro
I recently did a tummy tucker skid plate. I did a 1" body lift and a 1" motor mount lift before it, then the tt, which pushed the t case up about 2". I gained about 2.5" clearance underneath but now I have a .......new sound.

In 1st-3rd when accelerating I hear this grindy wobble vibration-ey noise. If I am easy on it and drive like an old lady I don't hear notice it.

I BELIEVE this to mean my pinion angle is off because of the tt and the 2" lift the tc got.

What is the best way to address this or do I have another problem?

If I'm right about the pinion angle, I can get a CV drive shaft (best cheapest option?) or adjustable control arms upper and lower.

Which is best to address the pinion angle. If I'm getting a new driveshaft should I go ahead and do a lift first and have the driveshaft made for the new lift AND tt?

If I need a drive shaft I KNOW I'm going to Olivers based on everything I have heard and read.

So, where am I and what direction should I go?
 
Tj or yj

You need a sye and a dc shaft either way. And to adjust pension angle if.you.have a tj you need adjustable control arms if.a.yj you need spring wedges or remount through spring perches

Sent from my HTC Incredible using tapatalk
 
Sorry, LJ Rubicon.

I looked at the pinion angles and its "tweaked" at the diff AND at the tc. I think, what say ye?

aimg843.imageshack.us_img843_5760_20100919104950.jpg

aimg842.imageshack.us_img842_4476_20100919105006northlibe.jpg

aimg685.imageshack.us_img685_1032_20100919105018northlibe.jpg

I THINK I want something like this for the RUBI.

aimg101.imageshack.us_img101_7126_rubiconrear.jpg
 
Can you adjust your pinion angle?

I would adjust the pinion down some, it looks like it is straight with the driveshaft as it sits now. It needs to be a few degrees below straight. When you apply torque due acceleration it will cause the pinion to rotate up and it will be straight then, currently it is rotating to far up.
 
I did this for mine, picture was before the pinion angle was set

ai298.photobucket.com_albums_mm279_burrellsjeep_006_4.jpg_2b5382a6b00352e072acf1fa7f83a656.jpg


XJ front drive shaft from a junk yard cut down and balanced at a driveshaft shop.
 
Can I adjust OEM arms? I thought i neeeded aftermarket. If that's the case I'm going with ironman4x4s. Could I get adjustable uca and lcas and adjust the pinion angle and NOT need a driveshaft?

The price will be about the same I believe.
 
IMO your going to need both in the long run. Cant adjust OEM arms.

But did my Drive shaft for less than a $100.

Driveshaft $25 - junk yard, or you find them on here from part outs.
Cut and Balance - $75 depending on the shop that does the work.

I would that route first, the angle is not that bad at the pinion. Just needs some tweeting, Have you went though any u joints at the pinion?
 
I've had the TT on less than a week and had one run up Daniel and a trip through the rock garden at URE. The noise DID seem louder AFTER URE.:lol:

Can I take my shaft tot Olivers and get them to make mine a CV or can I just give him the length and have one made?
 
Tech11 said:
I've had the TT on less than a week and had one run up Daniel and a trip through the rock garden at URE. The noise DID seem louder AFTER URE.:lol:

Can I take my shaft tot Olivers and get them to make mine a CV or can I just give him the length and have one made?
Click to expand...

Yes you can measure from the center of the u joint on the pinion and the flange on the transfer case and he can make you one.

Like this
awww.4xshaft.com_rubicon_RubiconMeasure_575x230.jpg


Just let him know it has a flange on the transfer case
 
Then sell my old one!? :bounce2:

SO the BEST Thing is to do the DS and not CAs.....yet?
 
I forgot. If I plan on getting a lift should I do it NOW, THEN measure for a new DS?
 
I just ordered an OME lift kit from DPGOffroad. I was told that since I did the TT and raised the TC 2" that the lift kit will/SHOULD bring everything back into proper alignment.

I went with the kit that has front and rear adj. trac bars, quick disconnects and rear sway bar links.

I also went with long travel shocks for when I get my super flexy control arms.
 
Tech11 said:
I just ordered an OME lift kit from DPGOffroad. I was told that since I did the TT and raised the TC 2" that the lift kit will/SHOULD bring everything back into proper alignment.
Click to expand...

Who told you this?

If anything lifting the Jeep is going to add to the vibration. The axles and the pinion are going to the be the same height as before and the transfer case will be higher due to the lift causing the angle of the drive shaft to be steeper and the angle on the u joints worst causing a greater need for a CV Drive shaft.
 
burrellsjeep said:
Who told you this?

If anything lifting the Jeep is going to add to the vibration. The axles and the pinion are going to the be the same height as before and the transfer case will be higher due to the lift causing the angle of the drive shaft to be steeper and the angle on the u joints worst causing a greater need for a CV Drive shaft.
Click to expand...

I asked about the driveshaft, and said since I needed to have the lift in BEFORE I got a new DS he said I MAY NOT need a new drive shaft since everything was raised EXCEPT The suspension, that the suspension lift could make everything closer to factory. Also because it's an LJ and the shafts are longer. Maybe I mis understood?
 
Thats why I suggested getting the lift before the DS was be cause the Jeep was going to get taller and the driveshaft would need to be longer. Wasn't aware yours was an LJ also, that will help a ton. I am not sure what they ment by the suspension moving up.

How much lift did you get?
 
2" OME heavy duty coils with long travel shocks.

I currently have 1" BL, 1" MML, and the TT skid plate. I'm planning on running 285/75R16s, I don't think 315s would stuff as well.
 
Tech11 said:
I asked about the driveshaft, and said since I needed to have the lift in BEFORE I got a new DS he said I MAY NOT need a new drive shaft since everything was raised EXCEPT The suspension, that the suspension lift could make everything closer to factory. Also because it's an LJ and the shafts are longer. Maybe I mis understood?
Click to expand...
Either you misunderstood or the person you were talking to was a retard. Raising the case is the same thing as adding suspension lift as far as driveshaft angles are concerned. You've gone up 2" on the case and are now going up 2 more with springs. Guess what? That = a 4" lift to the driveshaft angles. To do it right, you need the CV shaft and adjustable uppers. Gotta pay to play.

Edit: Looking at your pic of your d-shaft angle, you clearly are a few degrees low on the pinion. Adding springs will make this worse. Now, back to the original sound you were hearing. I'm willing to bet most of the sound on your hard accelerations is the trans knocking the tunnel. When you go belly up, even with a BL, there's not a lot of room in there.
 
willness33 said:
Either you misunderstood or the person you were talking to was a retard. Raising the case is the same thing as adding suspension lift as far as driveshaft angles are concerned. You've gone up 2" on the case and are now going up 2 more with springs. Guess what? That = a 4" lift to the driveshaft angles. To do it right, you need the CV shaft and adjustable uppers. Gotta pay to play.
Edit: Looking at your pic of your d-shaft angle, you clearly are a few degrees low on the pinion. Adding springs will make this worse. Now, back to the original sound you were hearing. I'm willing to bet most of the sound on your hard accelerations is the trans knocking the tunnel. When you go belly up, even with a BL, there's not a lot of room in there.
Click to expand...

Is it okay to drive around? Like yadkinville to gboro or do I need to drive it as little as possible.

I WILL need adjustable uppers? Front and rear or rear only?
 
If its knocking then its not as bad, depends on whats knocking. If its a shakin vib then becarefull driving it. Your pinion in the front will be fine.


Looking at the drive shaft again, its not that bad, Willness he has a LJ which has a longer wheel base and allows for more angle.

I didn't consider the knocking in the tunnel, which is quite possible its the issue. But thats just guessing.

Info I found:
You only want to raise the pinion and point it at the transfer case after you have a SYE and CV driveshaft. Otherwise, with the stock driveline you want both angles at each end of the driveshaft the same. See the crude diagram delow.
aericsxj.com_random_dsangles.jpg

Both angles A and B appear to be equal. In theory, this is what you want because each single cardan (u-joint) creates its own oscillations (vibes). With both of these angles the same, they should cancel each other out. The problem with this setup IMO is when you add in axle wrap, the angles change causing the vibes to not cancel each other out.

I can only recommend the proper way to do it which is do the SYE and a CV driveshaft. The CV joint (or double cardan) has two u-joints splitting the amount of angle A by half. With this setup you to point the pinion upward toward the transfer case. The pinion should be in the same plane as the driveshaft (zero angle), but to account for axle wrap you set it 1 - 3* lower. This allows the single u-joint at the pinion to operate under ideal conditions which is at no angle at all or very small angles.
 
I looked at Olivers site and they have the same thing tom woods has.

I'll leave the balancer thing on the TC side, get the double cardan cv shaft like what I posted above, and SHOULD be able to leave the control arms alone FOR NOW? right. BUT I must measure AFTEr the lift is installed.
 
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