Vibration - driveline?

[maggsie]

The disco has 80000k's on the clock and has developed a vibration particularly around 75-90kph. I have replaced the three front p/shaft uni's and centrebearing. I drove the car today without the front prop and the vibration is still there plus noticeable backlash when I back off the accelerator, which was not evident before I removed the front prop. I intend changing the rear prop universal joint and I'll have a look at the rotoflex joint when I remove the prop. Any thoughts?

Regards
Maggsie
04 V8 Disco

[justinc]

The disco has 80000k's on the clock and has developed a vibration particularly around 75-90kph. I have replaced the three front p/shaft uni's and centrebearing. I drove the car today without the front prop and the vibration is still there plus noticeable backlash when I back off the accelerator, which was not evident before I removed the front prop. I intend changing the rear prop universal joint and I'll have a look at the rotoflex joint when I remove the prop. Any thoughts?

Regards
Maggsie
04 V8 Disco

The Noticeable backlash is the fact you are driving through the trans in lock. It is quite bad isn't it??:(

The vibration could be the rotoflex joint on the rear shaft, but what engine revs does it come in? Is it possible that it could be an engine mounting collapsed. If you slip it into neutral does the vibration change with engine at idle?


JC

[Slunnie]

I was also thinking Rotoflex, except they usually vibrate in the low gears such as when taking off. This is how they look when they shag up.

https://www.aulro.com/afvb/images/imported/2010/03/640.jpg

[maggsie]

I've replaced the rear uni-joint and the rotoflex looks as good as new. I'll test drive tomorrow morning and see if there is any difference. Fingers crossed!

Thanks
Maggsie.
04 V8 Disco

[DaveF]

If it is still vibrating undo the 3 donut/coupling bolts to the diff and check if there is any up and down play/movement of the shaft on the locating spigot. If there is replace the bush in the shaft. this was the solution for me after fully rebuilding the front prop shaft and balancing the rear prop shaft.

Cheers
David