Driveshaft Angle

[Rickman]

I recently purchased a 97 wrangler tj, it had a 4 cylinder automatic and the guy I bought it from did a 4.0 5 speed swap. The drive shaft angle seemed to be off compared to a stock tj, it did well even on the highway. I installed a 4" lift kit with a tc drop kit, sent it to the local shop and had all the suspension dialed in but now it has a vibration so bad that you cant really drive it faster than 25-30 mph. Could something be off in the tranny/tc mount that is leaving the output shaft to high in the rear? Any feedback would help. I did order a sye kit with a cv driveshaft. What bothers me is that I have three friends with the same Jeep and the same lift with a tc drop and they all work fine.

 

[JeepNWilly]

Here is a picture of proper driveshaft/pinion angle

 

[PStov98TJ]

Different jeeps react differently to changes in suspension height. First make sure your driveshaft is at a proper angle. If it is, and you're still getting vibes, installing a sye/cv setup will likely eliminate them. Only other option is to go with a smaller lift.

 

[Jerry Bransford]

4" of lift is a tall lift, just a 1" tcase drop is seldom enough to get rid of the vibrations completely. You could temporarily drop the tcase further to get rid of the vibes. Don't screw with the rear pinion angle, it needs to stay at the factory angle until you install the SYE kit and CV driveshaft. At that time you'll need to raise the rear axle's pinion angle so it looks like the bottom drawing in the above illustration.

When properly installed and the rear axle's pinion angle is set as shown above, the SYE kit and CV driveshaft will completely eliminate all vibrations. You will be able to completely remove the tcase drop at that time.

 

[Kevin E]

Test it out with the rear driveshaft out.

 

[bobthetj03]

Test it out with the rear driveshaft out.

He can't. Doesn't have the SYE yet.

 

[Jerry Bransford]

He can't. Doesn't have the SYE yet.

Yes he can drive it with the rear driveshaft out, shift into 4Hi. Though I don't know what benefit there would be to doing it, it's well known the rear driveshaft will vibrate with a 4" suspension lift with just a 1" tcase drop.

 

[bobthetj03]

Yes he can drive it with the rear driveshaft out, shift into 4Hi. Though I don't know what benefit there would be to doing it, it's well known the rear driveshaft will vibrate with a 4" suspension lift with just a 1" tcase drop.

Wouldn't the slip yoke slide off and dump all his TC oil?

 

[Jerry Bransford]

Wouldn't the slip yoke slide off and dump all his TC oil?

No, that problem only existed with the 1995 and older Wrangler YJ. The TJ's 231 and 241 tcase output shafts are both completely sealed. You've been reading too many inaccurate catalogs that keep scaring people about that.

 

[bobthetj03]

No, that problem only existed with the 1995 and older Wrangler YJ. The TJ's 231 and 241 tcase output shafts are both completely sealed. You've been reading too many inaccurate catalogs that keep scaring people about that.

So if the rear drive shaft is removed, what keeps the slip yoke on the rear output shaft, other than the rubber boot?

 

[Kevin E]

1-1/4" nut

 

[Kevin E]

Sorry I'm thinking of my sye. My bad

 

[JeepNWilly]

Like Jerry said you can just slip out the Dshaft. I did this myself back when I had my old 4" lift and no SYE.

 

[bobthetj03]

Like Jerry said you can just slip out the Dshaft. I did this myself back when I had my old 4" lift and no SYE.

No, that problem only existed with the 1995 and older Wrangler YJ. The TJ's 231 and 241 tcase output shafts are both completely sealed. You've been reading too many inaccurate catalogs that keep scaring people about that.

Well I guess I learn something new every day. You still have to cut the clamps and remove the dust boot, correct?

 

[JeepNWilly]

Correct

 

[Rickman]

Thanks for all your advice, there was a lot of good info. I thought of pulling the rear driveshaft just to know that I know that's the problem, but the front was squealing and had some play at the tc so I pulled it and tried that. It was a definite difference, but still the same result. I'll wait for my sye kit with my new cv driveshaft and go from there.

 

[Rickman]

SYE kit showed up and as I was getting ready to drop the transfer case out I had trouble removing the rear driveshaft. The driveshaft was completely bottomed out at the slip yoke to the point where I had ti lift the jeep by the bumper to get the driveshaft out. I now think that maybe it had the wrong driveshaft which was too long. It's confusing that a stock driveshaft with a 4" lift would be that tight.