My 1999 Jeep Cherokee has really bad vibrations at highway speeds. It has a SYE with a front shaft in the rear. The vibrations started after I went from 3.5" lift to 6.5" lift.

I have replaced the U-joints twice, and removed the front shaft to see if that was the issue but have not yet put the front shaft in the rear to see if that will help.

YouTube brought the quality of the video down but if you watch it near the rear end you may see. But let me know what you think if that small of a bend would cause like 'high' pitched vibrations.

https://www.youtube.com/watch?v=3kA9V1FiDVU

thanks,

-Mike

Not bent. Not enough to create a vib. What year did you pull that shaft from. I'm not seeing a balance weight where one should be.

Not sure, i bought it from a jeep parts guy a while back. It did measure the same length as the front IIRC. When u watch the shaft with ur eyes it looks more wobbly than the video, but not by much.

Also, I think there is a weight on it by the back right in front of the rear yoke enless that's not it. where should the weight be?

Thanks,

-mike

Any chance the driveshaft came apart when you did the lift and got put back together 180 degrees opposite of what it should be? A buddy of mine had that problem once It's an easy 5 minute fix

There should be a weight on each end. One near the axle



And one up near the cardan. If its missing one it will vib to pieces.

Okay i took two photos this morning and it looks the driveshaft has some sort of weight or something attached.

Also, I did not take the shaft apart. Idk if it ever was but this thing was smooth with 3.5". I put the 6.5" on a year ago and have been dealing with this issue for that long.

You can try disconnecting it at the yolk and rotating it 180 degrees and seeing if that helps, if not, disconnect from the TC and rotate it 180 degrees at the TC and put the rear back where it was. That'll give you three different mounting options. It may help and it may not, but, it's free.

So I put the front shaft in the rear and the vibration issue is about 70% better, I'm guessing the other rumbles are the tires and the fact it's a jeep. So either the slight bend or possibly unbalanced shaft is the issue. It's about 75$ to get balanced and will hopefully fix it, $50 for another used one but it could make things worse or a nice $300 Tom woods shaft.

This is a shot of where the driveshaft took a smack, I know it's the greese coupling but still.