Help ID vibration/noise @40 MPH - 50 MPH Disco 2
 

I have a 2002 Discovery 2 SE, 62,000 miles.

Scenario is when accelerating all is smooth and good until almost exactly 40 MPH, at this point (every time) a vibration and noise start. It is a low hum/buzz that sounds a lot like the tires were all of a sudden hitting the rumble strips on the side of the road although not really that loud or obvious. The hum seems to decrease significantly as soon as I am accelerating over 50 MPH although not completely.

The sound/vibration only happens when accelerating. When I let off the accelerator at any speed above 40, it completely goes away.

I can feel the vibration through the pedal/body. I cannot feel anything through the steering.

I had the front driveshaft replaced about 5 thousand miles ago.

Any idea of what this issue might be or how I could systematically figure out how to approach resolving it?

Thanks in advance

Rear driveshaft Roto-flex coupler would be a place to start. Look for cracks/wear.

May be a tire issue as well.

Either way, since you say it is not felt through the steering, I would suspect the issue is located in the rear driveline.

Scout,

Thanks for your reply. I looked at the coupler and it looked all good, no apparent wear or cracks, etc.

When I get back in town I'll have to get under for a more complete inspection. I think I may take the front drive shaft out and lock the CDL to eliminate that portion of the drive train as a test.

^ good plan

Get all 4 wheels off the ground with a lift , and check wheel bearings , if the wheels shake from the hub area , they may be worn or just loose.. then check rear diffs

Will do, thanks for the advice.

Resolution
 

Was working in the Jacksonville area and found British 4x4. Took the disco over to James, he put it on the lift right away after a test ride and checked the drive train.

In the end with some significant diagnosis turns out the front dif was mostly full of water and there were metal shavings. The dif was rebuilt, but still some vibration left. James swapped the front drive shaft, replaced only 5k miles ago and the vibration was gone. Said my mechanic got the drive shaft for a 03-04 instead of my 02.

Rides like new. Really pleased with the help I got.

Glad to hear you solved it.... now that you know it was water , be sure to check the breathers on the diffs , if there's no lines... put some lines in them , and extend the high up under the vehicle ( with the opening facing downwards , to prevent water from flowing in freely)

Ryan,
Thanks, I will look into that. Appreciate the advice.

No Probs bro.... I know the headache it could prevent ...