Vibration..

[John T]

What can cause diff vibration ??

I fitted new diffs last week and now have a vibration on take off and at arround 50 mph, I do have a 2" lift, but never had any vibration problems before. The only other thing I have done is fit QT radius arms.

Any ideas please.. :roll:

[Staffy]

The QT radius arms sound like they could be the cause.

These when fitted tilt the axle back to it's original angle (diff sits level rather than tilted up to the transfer box), therefore the prop is at a more severe angle than it was before, which puts the uj's under a much higher strain. Hence the vibration.

The usual cure is to change the prop.

Phil

[muddymart]

The usual cure is to change the prop.

Phil

Dont forget to get the td5 flange as well as its wider and will fit the td5 front prop with the two yokes,

im learning all the time, you should see my back room with all the parts in for the 2" lift, im going to get it all done at the same time....

Good luck !

[NY4x4]

The QT radius arms sound like they could be the cause.

These when fitted tilt the axle back to it's original angle (diff sits level rather than tilted up to the transfer box), therefore the prop is at a more severe angle than it was before, which puts the uj's under a much higher strain. Hence the vibration.

The usual cure is to change the prop.

Phil

But surley the prop is now back at the correct angle, and should have been a problem before the Qt's were fitted..

[Darren]

The castor correcting radius arms are designed to correct the steering geometry, which can be upset by a lift because the axle is tilted forward. They also solve the problem of the UJ's not running parallel with each other when the suspension is lifted, which puts extra strain on the joints, although that's not their prime purpose. However, this does mean that the whole propshaft does run at a steeper angle, which can be on the limit of operation of the original joints.

As suggested above, the solution to that problem is to fit a double cardan jointed prop from a TD5, or a wide angle standard prop, both of which are able to run at steeper angles.

[Eeyore]

Going to have to disagree here, but a wide yolk prop won't make any difference. They're designed to work through a greater angle before binding (and arguebly tolerate greater torque) - they still wear at the same rate as any other conventional prop, so any fix a wide-yolker would proide would only temporary, I'm afraid.  :(

Double-cardan is the way to go if it's the prop that is causing the proble, but considering the probelm wasn't noticed before the QT arms were fitted it would point heavily at the prop being the issue. A DC prop will halve the working angles of the working bits and this increases lifespan by severel orders of magnitude - it also irons out some of the impulse loads which is very important on diesels! Again it all helps to make the UJs last a lot longer.

Whatever you do - don't go to a general LR shop and buy one - go to a specialist prop builder like Propshaft Clinic or Dave Mac Propshafts. You can potentially save a small fortune! Having said that Devon 4x4 are fairly reasonable for props, but they still can't beat the specialists.

Hope this helps
 8)
Eeyore

[Iain C]

Agreed, probably the prop.  I bought my Disco 9 months ago with a knackered front prop, changed it, all was quiet.  Lifted it 2" and my prop UJs were shot again in under 2000 miles, symptoms very similar to what you describe.

However, I may have fitted the UJ incorrectly the first time and knackered the thing... :oops:

[Eeyore]

To be fair, you probably haven't. I've lost UJ's in less than 600 miles on a lifted vehicle (but I was trying!   ). I've had a DC prop on for about 30k miles and haven't heard a thing from it.

.....well, the mounting bolts keep working loose, but LR props seem to do that!  :lol:

Cheers
 8)
Eeyore

[lee celtic]

Try taking the props off rotate them 180 deg and put them back on might just be a balance thing

remember cheapest option first = spare beer tokens. :D

[NY4x4]

Try taking the props off rotate them 180 deg and put them back on might just be a balance thing

remember cheapest option first = spare beer tokens. :D

Sounds good to me...    :lol:

[4 landies]

Will the TD5 dc prop fit on a 200tdi aswell as a 300 if i change the flange

[clbarclay]

The castor correcting radius arms are designed to correct the steering geometry, which can be upset by a lift because the axle is tilted forward. They also solve the problem of the UJ's not running parallel with each other when the suspension is lifted, which puts extra strain on the joints, although that's not their prime purpose. However, this does mean that the whole propshaft does run at a steeper angle, which can be on the limit of operation of the original joints.

As suggested above, the solution to that problem is to fit a double cardan jointed prop from a TD5, or a wide angle standard prop, both of which are able to run at steeper angles.

Close but no cigar, I've been here before with land rover props :roll:


Coil sprung Land rover transpher box output and diff input are designed not to be parrallel. When standard the UJs have the same working andgle and are phased so that the constant acceleration/deceleration of the first UJ is canceled out by the second UJ.
If you ever pull the sliding part of a propshaft apart mark it first so that when reasembled the UJs are still correctly phased.
When lifted the UJs no longer have the same working angles, with means for a constant transpherebox output the diff will be constantlly accelerating/decelerating which causes vibration on vehicles that have been lifted too much.

<pausesforbreath>


On vehicles that are lifted and then fitted with castor correction arms the working angles of the UJs are further changed. The top UJ is at an evan greater angle and the bottom UJ has a reduced working angle causing greater inbalance than before the arms were fitted.

A double cardon joint is effectively 2 UJs phased and constantly at the same working angle so that there is virtually not vibration. This replaces the top UJ which is at a greater working angle. The bottom UJ on a lifted and arm corrected land rover has little working angle and which changes very little, so a basic UJ can still be used withough casuing noticeable vibration.
 :D

[Range Rover Blues]

What he said.

As a bodge you can remove some of the vibration from a lilfted LR by lining uup the UJs on a standard propshaft, as the lift alters the UJ phasing, but once you fit castor correctio there is now better way than fitting some sort of CV joint.

Out of interest I have noticed that the phasing of the front prop is greater on later RRC, being about 45degrees.

[barmiebrumie]

Will the TD5 dc prop fit on a 200tdi aswell as a 300 if i change the flange

Yes,  just done mine