Rhythmic Vibration at Highway Speed

YonderNorthwest

YonderNorthwest

TJ Enthusiast
Supporting Member
Joined
Dec 29, 2020
Messages
164
Location
Portland Oregon
Got on the highway last night and noticed a pulsing vibration. I'd say its about 1 second of vibration (more like a deep hum) followed by 1 second of nothing. I am noticing it most through my foot on the throttle. I asked my passenger about it and she felt it as well. Vibes go away at around town speeds.

Jeep has 225k on the clock. Stock height, so not pinion angle. Front and rear axle u-joints were replaced ~10,000 miles ago. I plan to climb under and take a look tomorrow. I took a look at the driveline section of the service manual and I'm guessing it's either

a.) drive shaft u-joints
b.) wheel bearings
c.) drum brakes

Anything else I should be looking for when I get under there tomorrow?

Thanks
 
It's probably A.

When was the last time you had the driveshafts balanced?
 
xXDavidCXx said:
It's probably A.

When was the last time you had the driveshafts balanced?
Click to expand...

Never? I had LSD's put into the front and rear about 18 months ago, new control arms about 2 years ago, and the axle u-joints I mentioned above. Other than that the driveline hasn't been touched to the best of my knowledge.
 
Do you know whether Spicer U joints were used or cheap Chinese knocks off from the local AP store ?
Even though the U joints were replaced 10K ago; the knock offs are known to no last as long
 
Fought with the same problem for years. I replaced all kinds of parts. I got the vibes down to a minimum after changing the skid plate oddly. The vibes were still there tho. I went with a hub conversion and absolutely love it! Easily my favorite mod besides heated seats. You wouldn’t believe how much quieter it is when you don’t hear the whole front axle turning at 65mph. A few things you should check are the pinion nuts and front output shaft nut on the driveshaft. Mine loosened up multiple times over the years. Sounds like you had a bit of work done just make sure it’s all tight.
 
Start with removing the front driveshaft.
 
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