Thread: crazy drive line vibration

I had a harmonic vibration that came in after 60 KPH was 'orrible at 80 KPH and was gone by 100 KPH. Turned out that one of the mechanics at my dealer had reassembled the front propshaft in the wrong alignment.

fixed the alignment of the shaft and no noise/vibration.

If you haven't had any driveline work lately it's not the same problem but may be worth a look at the joints.

Diana

Defenders get worn drive flange bolts( mainly on the front) and the uni s suffer from high rates of wear.
Check the uni alignment by all means.
Also check the diff and transmission drive flange splines for wear and loose retaining nuts especially.
A tail shalf which has been hit off road and and slightly bent will cause problems too.

Another point of note is both uni jionts must run at the same angles.
A suspension lift or rotated drive line will upset this a cause exactly the above vibs on the float when backing off.

Originally Posted by 101 Ron

Another point of note is both uni jionts must run at the same angles.
A suspension lift or rotated drive line will upset this a cause exactly the above vibs on the float when backing off.

Correct for rear only, but not at the front for coil sprung rovers.

so far i have had a closer look at the front shaft and replaced the front unis the front shaft is out of a early rangie as the defender shaft had seized on the slip joint and could not be repaired it had this problem before fiting the front shaft from the rangie so i dont think its the shaft im going to smash a new set of rear unis in it seing there prety cheap and see where that goes. have replaced one rear uni a few months ago with a secondhand one out of the old front shaft because i was in a bind and had to go away before i could get a new one and noticed the rear shaft was out of phase by one spline on the slip joint so i put it back in phase my under standing is only the front shafts are ment to be out of phase after a drive tonight its feeling like it may be the rear but its very hard to tell as it only does it for a second when backing off from 100 plus and no vibe on acceleration

Originally Posted by 460cixy

so far i have had a closer look at the front shaft and replaced the front unis the front shaft is out of a early rangie as the defender shaft had seized on the slip joint and could not be repaired it had this problem before fiting the front shaft from the rangie so i dont think its the shaft im going to smash a new set of rear unis in it seing there prety cheap and see where that goes. have replaced one rear uni a few months ago with a secondhand one out of the old front shaft because i was in a bind and had to go away before i could get a new one and noticed the rear shaft was out of phase by one spline on the slip joint so i put it back in phase my under standing is only the front shafts are ment to be out of phase after a drive tonight its feeling like it may be the rear but its very hard to tell as it only does it for a second when backing off from 100 plus and no vibe on acceleration

Correct, rear prop shaft has the joints in phase. A possible cause of the vibration is failed or loose engine or gearbox mounts, either transmitting vibration or allowing something to touch as the engine assembly moves, going from drive to overrun.

John