Jeep Cherokee Rumble

[Nick1994]

Trying to solve my 96' Cherokee 4.0L 4x4's highway rumbling that it's had for years.

Going over 65 brings it on, it sounds like bass, like a subwoofer. Gets louder with speed. Sounds like it's coming from somewhere in the front half of the Jeep maybe? It'll do it on jack stands with the rear wheels/drums off.

-New from dealer OEM motor/transmission mounts
-New wheel bearings
-New front axle bearings
-All new U-Joints for both driveshafts, from a driveline shop and both balanced there.
-Have replaced the rear axle since it started doing it.
-New output bearing in transfer case
-New tires
-New catalytic converter
-Have replaced transmission fluid and transfercase fluid.

Here's a video of it, nothing to see, only audio. Unfortunately there isn't a lot to hear if your speakers don't have bass. About 6 seconds in it downshifts (that's the engine sound). I speed up from 65-80 or 85 then back down to 65 in this video.

Has AW4 automatic. Can a bad flex plate do this? Transmission? It shifts great, bass does seem a little louder/harsher when accelerating but is not really RPM dependent, it's speed over 65.

Any help is appreciated.

 

[Skippy722]

I would put my money on drone or everything aligning just right to hit a resonant frequency.

 

[SwampSurvivor]

Put a small amount of pressure up or down on the transfer case lever. Not enough to shift it, just enough to take the slack out of the worn out plastic bushings.

 

[jeepman3071]

Originally Posted by Miller88
Put a small amount of pressure up or down on the transfer case lever. Not enough to shift it, just enough to take the slack out of the worn out plastic bushings.


+1

Also were the front axle shaft u-joints replaced?

 

[JLTD]

No bass (as you mentioned) on phone speakers, so didn't hear it....possibility it is some wind intrusion noise?

 

[Sunnyinhollister]

front axle shaft u-joints?

 

[mk378]

I thought the only noise that Jeep owners cared about was the unexpected quiet after a part fell off.

 

[t1snwrbrdr12]

Pinion bearing(s)? I haven't watched the video, though.

 

[t1snwrbrdr12]

I listened but I'm not really sure what I heard, sorry. But if you have good wheel/hub bearings, new axle u joints, there aren't really any axle bearings on that front end, carrier bearings aren't really speed dependent noises, I'd have to guess pinion or front driveshaft/transfer case noise.

Is it lifted or anything to have affected driveline angles? Driveshaft joints didn't usually wear out on any jeeps id ever worked on, and I worked on some with 300+k miles.

 

[Nick1994]

Stock height, not lifted

 

[Skippy722]

Ooohhhhh a clean unmolested Cherokee!

I'm sorry but it is clearly totaled. I will be down to pick it up for you though

 

[dlundblad]

Removing the front driveshaft is also an easy test to see if it's driveline related.

I had this issue with my Jeep, but it was a faulty rzeppa joint. Would only make noise at highways speeds.

 

[Nick1994]

Originally Posted by dlundblad
Removing the front driveshaft is also an easy test to see if it's driveline related.

I had this issue with my Jeep, but it was a faulty rzeppa joint. Would only make noise at highways speeds.

I think I did that once. It makes the sound with the rear on jack stands.

 

[dlundblad]

So it's either something at the transfer case on back or motor mounts maybe. Unlikely since they're new and OE but possible nonetheless.

Any chance the rumble is from the tires? My Jeep's AT's change their tune depending on speed and are very vocal in the rain.