Vehicle & Technical > Discovery

The famous vibration after doing a lift?

<< < (2/6) > >>

Budgie:
If you've got a 200 Series with the LT77 gearbox then these tend to ware the gearbox mainshaft where it fits into the drive gear on the transfer box. This is due to the lack of oil getting to the shafts and the 'clunk' when taking up drive is normally heard from around the handbrake area.
Early 300's also suffered from this but there was a modification to the input gear that solved the problem around 1995.

If you're getting a vibration through the steering then the common cause is the front propshaft U/Js. You need to get under there and grab each U/J and give it a good shake. If there is any movement then it needs replacing.
The only way to check the centre spline on the propshaft is to remove the shaft at one end and see if it works.

Other causes of the vibration:

Swivel housing pre-load needs tightening - jack the front wheel, grab the tyre at the 6 & 12 o'clock position and try to move it in & out. If you have a spare person then get them to look at the swivel housing seal, if they can see movement or you can feel movement the take a couple of shims out from under the top pin. Refer to the manual for the correct pressure using a spring scale.  :wink:

Wheel bearings - same check as for the swivel but hold the tyre at 3 & 9 o'clock.

Worn suspension bushes. Panhard rod is the most common one to go.

Track Rod ends.

Exessive play in the steering box or drop arm balljoint.

Steering damper needs replacing.

Wide yoke propshafts don't stop the vibrations set up by a suspension lift and this is normally only caused when you fit a set of caster correction radius arms. The radius arms alter the angle that front propshaft works at, the diff end is nearly straight and at transfer box end is nearly binding. This sets up a 'pulsing' in the propshaft which is normally cancelled out by both U/Js working at the same angle on a standard setup. The only way to stop this is to fit a Double Cardan propshaft which lessens the angle the top U/Js are working at. The wide yoke propshafts do have more movement but still suffer from the 'pulsing' problems.  :wink:  

Have fun!  :D

nickW:
i thought it might be UJ's as the vibrations seem alot worse at certain speed as if the the uj was alright at slow rotations, and at high rotataion ie above 50mph the centrifugal force probably stopped it moving around so much, but at 40-50 its spinning slow enough to through its self alover the place, its only a thought though?

also the vibration doesn't seem to come throught the steering more through the body and chassis of the truck, maybe the rear

Budgie:
In that case then check the propshafts first, remember to chock the wheels & release handbrake before you do the rear one!  :wink:

Is it a 200 or 300 Disco you've got?

nickW:
yeah its a 200 what am i looking for on the propshaft

Budgie:
All you have to do is grab the prop near the U/J and try to move the prop in all directions (except round as there will be some rotation due to play in other parts of the drivetrain). If you feel any movement like a slight knocking in the joint then it's best to replace it. You can pump grease into it as a short-term fix if you can't do it right away.  :wink:

Sometimes you can see the movement if you look close at the yokes.

As you have a 200 then you've got the LT77 gearbox which does suffer from a 'clunk' when taking up drive, as I said about above. If yours is suffering from this, and provided it's not too bad, then you can change the transfer box input gear for the later mod'ed one that has oil holes in it. This can lessen the play between the gearbox mainshaft & the input gear.

Another place that these 'clunk' on take-up is the axle drive flanges where the halfshaft meets the hub, these are easy to replace and quite cheap as well.  :wink:

Navigation

[0] Message Index

[#] Next page

[*] Previous page