Interested to seek the wisdom of the web to diagnose a driveline vibration and noise on my 2003 Disco with 87K miles.

I have what feels like a driveline vibration when the car is decelerating. More specifically:

If I partially LIFT OFF the throttle at highway speeds allowing the car to decelerate slowly, but do not lift off the throttle enough to allow for any engine braking, the car will vibrate. This is very easily replicated on down-hills where only partial throttle would be required to maintain road speed (neither accelerating or decelerating significantly).

The car runs smoothly on flat roadway while maintaining speed - partial throttle applied. As an example cruising down a highway at moderate speeds (e.g. 55-60 MPH)

If I FULLY lift off the throttle, allowing engine braking, there is no vibration. There is a very brief moment (less than one second estimated) of vibration only as the car transitions from constant speed to engine braking condition.

If I apply throttle to accelerate the car, there is no vibration.

If I disengage drive and allow the car to coast, say down a steep incline, there is no vibration (at least up to speeds of about 40-45mph). If I vary engine speed while coasting (transmission still in neutral) - there is no vibration.

When coasting to a stop from slow speeds (less than say 20mph), there is had been an audible "whir-whir-whir" - but this is now getting louder. I am having trouble determine where this sound is coming from.

I have recently replaced the front driveshaft with a Rovers North replacement (heavy duty unit for up to 2" chassis lift however my car still is stock suspension height).

I have drained and filled the front differential, rear differential, transfer case with fresh oil. While I did find some sludge and generally grungy oil, I didn't note any metal particles. I did change the transmission fluid as well.

I have greased the rear drive shaft - but not serviced the u-joint.

My next steps are to rotate tires (all show even wear with approx. 15K miles) - this doesn't seem likely...as coasting there is no vibration or noise.

Inspect the rotoflex - It would likely be original now with 87K miles.

Today, after trying to test in Lo / High - I now experience issues with the transfer case indicator light coming ON intermittently.

Thanks
Bill Kallgren

 

I have a similar 2003 Disco with 84K miles. Changed to new front driveshaft, new shocks, new brakes/rotors, new oil for transfer case, diffs and transmission, tires balanced.

There was still a high speed vibration. I inspected the Rotoflex which seems to be in great shape. I ended up changing it to a new one and the high speed "throbbing" vibration went away. The original Rotoflex looked to be in great shape..... no cracks. I was surprised a change to the new Rotoflex fixed the issue.

 

Have you rebuilt or replaced your front drive shaft, if not that is your vibration and it is about to fail which usually can take out the tranny at the same time.

 

Yes, my original thought was the front driveshaft which was the OEM unit. I did replace it with a Rovers North Unit "PROP SHAFT FRONT V8 DII 99-04 HEAVY DUTY"

It is rated for 0-3" lift which seemed a good idea as some day I would like to raise the car it a little.

The noise and vibration only seem to be getting worse. The car runs smoothly when in neutral coasting down a hill, wouldn't I still feel a vibration if the driveshaft were knackered?

My only concern with the 0-3" specification on the replacement driveshaft would be if the driveshaft is bottoming out under suspension compression putting extra stress elsewhere.

BK

 

Rotoflex coupler is a prime suspect.

 

Alright, my new rotoflex kit arrived. Easy enough to unbolt the old unit, a few hairline cracks under close inspection when bending it around - but appeared in reasonable condition, I would guess replaced by the previous owner, the bolts and rubber part looked OK. Rubber seals elsewhere for example show more deterioration.

My kit included a new seal which fits into the end of the driveshaft and slips over the differential centralizing peg (input shaft). I am guessing it has never been replaced - as this part was corroded.

I had a great row trying to pull old seal out of the end of the driveshaft...two beers of effort...lots of heat and banging away...in the process destroyed the old seal. Upon inspection of the new part, it isn't clear which is the correct orientation for fitting the replacement part. RAVE is silent on the point.

One side of the seal has a spring around the inner rubber boot, the other side the seal is flush with the housing.

Also, having had such issue pulling the old part out, is this a simple press fit or is it a shrink fit? I would prefer to install it in the correct orientation and not wreck it in the process.

Thanks
Bill

 

Guys,
Can a rotoflex be replaced with greasable U joints or a double U?

Pros for getting rid of Rotoflex?

Cons?

 

Yes here ya go:

Drive Shaft Conversion Kit For Land Rover Discovery Vehicles

 

Why would you want to. The rotoflex is quite strong, will take 3.5" lift and never just fail like a u-joint, they just gradualliy crack and c=shake over many miles and only cost $65 to replace.
By the way, don't worry about that sleeve unless your pinion bearing is throwing oil.

 

Mike,

Thanks for the advise on the sleeve. Having wrestled to get it out, I fit the new part with the flat face inserted into the propereller shart and the spring loaded side toward the differential. The seal fits over the centralizing pin more fully in this orientation.

With the new rotoflex installed, there is no change. Still have a vibration as detailed originally - am more worrisome is the now more noticable driveline noise.

The 2003 has no center locking differential - I am at a loss to on how to test to narrow possible causes. As a precaution it would seem prudent to remove and inspect the new front driveshaft (in case of infant mortality).

Are there checks for excessive end play or slop in differentials or transfer case?