Jeep info:
1990 XJ, 4.0L, AX-15, D35 w/lsd, 180K.
3" Tomken lift with stock driveline.
My XJ has recently developed a thrumming/throbbing noise from the rear end. It's a "whump-whump-whump" that is periodic, and which starts once the XJ is above 30mph or so. There's no vibration that I can detect.
Also, the noise only occurs when I'm on the gas/under load (disappears when I back off the gas).
Lift has been on for the past 5-6 years with no change, so I don't think its driveline angle or anything like that. I also don't suspect wheel balance, since that was done 2-3 months ago, and the noise isn't always happening (again, only when on the gas).
The only things I can think of are ujoint issues, or possibly the rear diff going bad. Any ideas or suggestions of what is wrong or what to look for are greatly appreciated.....
1990 XJ, 4.0L, AX-15, D35 w/lsd, 180K.
3" Tomken lift with stock driveline.
My XJ has recently developed a thrumming/throbbing noise from the rear end. It's a "whump-whump-whump" that is periodic, and which starts once the XJ is above 30mph or so. There's no vibration that I can detect.
Also, the noise only occurs when I'm on the gas/under load (disappears when I back off the gas).
Lift has been on for the past 5-6 years with no change, so I don't think its driveline angle or anything like that. I also don't suspect wheel balance, since that was done 2-3 months ago, and the noise isn't always happening (again, only when on the gas).
The only things I can think of are ujoint issues, or possibly the rear diff going bad. Any ideas or suggestions of what is wrong or what to look for are greatly appreciated.....