Thinks this may be in the diff?

[kippo1]

Ok regular driving any speed no grinding or vibration.

If I barely press the gas pedal say 1/4 in then I get a constant vibration until l let off gas or press it further.

Coming to a hard stop a bad grinding vibration from the front end that will go away if I let off the brakes and then easily reapply them. Now the vibration and grinding sound does not start till your at about 10 mph decelerating in the stopping process.

I have checked unit bearings, brake rotors and pads for rocks or other foreign objects, lug nuts for tightness. Now I don't remember it doing this before I put on wheel adapters and 17" moabs with new tires. Balance on tires is good.

So I have 4.5 in la lift, sye, 4.56 gears Aussie lockers, 5 on 4.5 to 5 on 5 wheel adapters,

Going to go out and try moving my yoke around and see if pinion has any play.

Just looking to see if anyone else has had this or other ideas on what to check.

Thanks

 

[831_xj]

So.. you think it's coming from front or rear? I'd say give a very thorough once over on all 8 ujoints

 

[kippo1]

Feels like the front. The sound definitely sounds like it is coming from the front. The axle joints and unit bearings were replaced last July when I regeared and did my lift and everything. If I can get my boy to sleep pretty quick I'm going to go out and do a little probing around.

 

[David_Bricker]

This almost sounds like two issues. For the 1/4 throttle vibration, I would suspect driveline U-joints. Can you remove the rear driveshaft, and run on just the front.

The grinding noise I don't have a good idea, though I would also check rear brakes. On my wife's Ram 1500 I could have sworn the left front brake was grinding - it turned out to be worn rear discs.

David Bricker / SYR

 

[kippo1]

I hope the drive shaft is still good it was new when I did my lift and regeared . I'll look into the rear brakes. I can pull drive shaft but will be sat before I can.

 

[kippo1]

Well bad news for me. The not real bad news is need to rebuild my front drive shaft. The bad news is I was checking rear drive shaft and the out put on my sye is shot. Maybe just bearing. I can grap the yoke and move it about .03 up and down. I am not happy. I have another sye new in box and another 231 in my parts jeep.

So I guess I'll pull the one out of the parts jeep and install the sye on it and slap it in mine and repair the other and keep it as a spare.

I wonder if these are the cause of both my issues.

 

[kippo1]

If your rear diff yoke angle is off by a few degrees from the angle of the double cardan drive shaft will that cause a sye output shaft bearing to go bad?

 

[David_Bricker]

If your rear diff yoke angle is off by a few degrees from the angle of the double cardan drive shaft will that cause a sye output shaft bearing to go bad?

No, it should not be an issue. The double cardan will allow for differing angles. When running a double cardan joint on for the front joint, the rear joint should be at near zero degrees. Generally, point the rear diff at the center ball of the double cardan. there is enough movement in the rear suspension of our Jeeps to keep the rear u-joint lubricated. (Specs call for about 1/4 degree to ensure the joint moves, but that's not an issue with flexy suspensions).

David Bricker / SYR

 

[kippo1]

Hmmm. I wonder why my out put shaft bearing went so hast. It's only been right at a year.

 

[highspeed]

Hmmm. I wonder why my out put shaft bearing went so hast. It's only been right at a year.

1 year since install of the SYE or the Output shaft bearing?


Could be any number of things that caused it, but like state earlier...you may have some small angle issues on the rear diff. Is the rear axle shimmed at all?

 

[kippo1]

Wil be a year next month since installing sye. No not shimmed I'll update with pinion and drive shaft angle later. I have to get back out to my buddy's shop where the jeep is now.

 

[kippo1]

I did take it for a test drive the vibes are gone but the grinding under hard braking is still there.

I also put currie Johnny joints in place of my flex joints and I could tell a world of difference from one to the other.

Here is the kicker. Since I put the Johnny joints in i have to brake really hard to get the grinding noise. I'm going to pull my front drive shaft tomorrow and see if the grinding goes away.