Noticed a sort of knocking/vibration on the highway in 4th around 2000 rpms. I'm not sure what a bad driveshaft feels like but its what i would expect. I got under the jeep and noticed the front drive shaft has grease slung around where it meets the tc. I bought the 2dr 6 spd with a 4" RC lift on 35s and have read on here that I will need a new rear ds soon but why would the front throw grease? Any way, how do I check the angles on the shaft to see how far I'm out of wack? Also, what all will be needed to get the geometry back in line.

Oh, and I was looking at Tatton cv drive shafts. Anybody use them? I'm kinda on a budget.


thanks in advance.

 

Come on...driveshafts...bump...

 

From what i have heard the front is the worst as it can contact the transmission skid and pan. Never looked them but lookes at tom woods and i rubicon express and they are both around 450 each...

 

The tom woods website has proved helpful. Thanks for the reply man.

 

It isn't uncommon for the front shaft to spit grease. From the height, that joint gets pinched and eventually wear through. Could be from flexing off-road, or just from normal driving - with the JK's 4x4 system, the front driveline is always spinning, even though if does not have power in 2wd. You would need to swap to manual hubs to stop it.

To change your angles, you will want to add a set of adjustable control arms. Look at front lowers to adjust the caster/pinion, and rear uppers if/when you replace the rear driveshaft. A second set on one end will let you fine tune and move the axle forward/backward in the wheel well.

But before you run out and buy a set, did your lift come with cam bolts or a set of longer/shorter fixed arms?

Down in the write-ups area, you will find an index at the top. There is a DIY Alignment writeup in the troubleshooting section that has some good info. It does not give the same numbers as an alignment rack, but will get you some numbers that people here will understand. (the gentleman from dynatrac posted a better way to measure caster/pinion, I'll post it if I run across it again.)

 

Your front drive shaft is done if it's spitting grease. You'll need a new aftermarket - Tatton's are good quality. At 4" of lift, you should look at front control arms if your lift didn't come with them to address the caster and pinion angle.

 

you should call around to local 4x4 shops.
you can get a custom shaft built with HD parts for pretty cheap
from local places sometimes.
I went that route with my old YJ.


if you're slinging grease time for a new shaft.

 

Hmm. I'm not sure as I didn't install the lift but if I had to guess I'd bet that RC didn't supply control arms. Though it does have cam bolts. How can the cam bolts help? Are they adjustable?
The lift is a 4" rough country performance 2.2.

I was thinking that since the rear doesn't seem to be throwing grease yet, I could get by on a new front ds, a set of front lower control arms and rear uppers and hold off on the rear driveshaft.

thanks for all the help

 

Cam Bolts allow you to adjust the caster/pinion of the axle, just to a lesser extent than a set of adjustable arms. If you choose to add adj arms, you will probably want to remove the cams and have the holes welded back up.

For the rear, you will want the adj's so you can point the pinion up toward the tcase. Up front, you need to balance the pinion angle (driveline vibes) against the caster (poor handling). The cams may get you the caster/pinion you need.

 

I just put new drive shafts on two days ago and they are working well. I got mine from Dave at northridge and he gave me a good deal. You might want to call him. My front one was spitting grease but my back one looked ok. I went ahead and replaced both of them and man i'm glad I did. when I took the rear one off the the joint fell into three pieces and the bearings fell out. It was the one that seamed fine too. If you want to go the cam bolt route I have a set of cams for the JK brand new in the box sitting in my garage ill give to you cheaper than u can buy them. They will make your handling a lot better if new control arms are out of budget right now.