unbearable vibration checked everything cant sort it any ideas welcome

hi
I have searched the forums and cant find anything to explain the problem
I have a 1992 200tdi defender trayback, used it last winter offroading then left it standing for 4/5 months so took it for a run to put some diesel in, few miles into trip it started a realy bad vibration under load so got home checked it over found shagged rear prop and play in front diff so thought i would spend all my savings and do it up so:
fitted new "stumpy" r380 box from ashcroft eng
2 axles second hand axles but just been fully rebuilt with arb air lockers, disco 2 diffs heavy duty shafts etc and never been fitted just bench tested
td5 transfer box
37" mudzillas
new shocks etc
2 new props 40 deg extra wide angle from bailey morris
it already had adrenaline 4x4 rear trailing arms, 4" lift, fully polybushed, qt 6 deg castor correction arms
all fitted got in and drove it SAME VIBRATION
at least it feels the same!! (maybe its something else that feels the same)
the whole cab dash wheel vibrates violently under load in any gear mainly at lower revs but still at higher revs
have changed wheels and tyres for 31's still does it
checked all mounts all ok
remove rear prop it stops so put the rear prop on my mates 90 with same lift and its ok so not the new prop
remove front prop and it seems to get a little bit better but hard to tell
wondering if the diff ratios may be different
so
not trans box
not props
not wheels
not bearings or bushes
not engine/box mountings
would love to burn it as just fed up now but spent too much to stop so must sort it
plleeease help
Thanks
forgot to add, had 2 garages look at it who know a fair bit about landys and they checked it all over and had no idea

also forgot to add
if i freewheel with clutch in at any speed it totaly stops

steering box

changed that last year but it stops with rear prop removed so tried my prop on another 90 and tried different prop on mine other motor was ok mine still vibrated so cant see it being steering box, and had it all checked and just flew through mot this week, with all new parts there is no play anywhere
forgot, put new steering bars and all joints etc this week also
but thanks for suggestion

Have you tried revving the engine up stationary?? The way you describe dipping the clutch at speed stops the vibration tells me it's engine vibration.

just read you second post so scrap that one, I reckon you driveline angles are screwed. you destroyed you old rear prop so there could be a bind/pinion angle problem that only shows under load.
The front could also be a problem as castor correction arms keep the diff pointing low, where it is good practice to correct the pinion angle then clock the king pin/castor angle

Gearbox mounting.

rear trailing arm to chassis bushes. or warped clutch or ouput flange/shaft

thanks for replies
driveline angles sounds interesting although never did it last year with old props but had all the arms etc fitted then but worth looking into, do you have any ideas how i would solve this if it is the problem (prop phasing !!) admittedly the adrenalin 4x4 rear trailing arms are 20mm longer than standard for a 4" lift so the diff is pointing straight (horizontal) neither up or down.
trailing arm bushes all poly bushed and checked, clutch etc, would it stop with rear prop removed ??
thanks for any ideas, gives me some hope of sorting it

get a cheap digital angle meter and check the diff pinion to rear of transfer box flange angle.
For correct kinematics the angles should be the same ie parallel.
Put your standard trailling arms on and see what happens

cheers Pressbrake
checked drive angles and were out
changed the trailing arms and all sorted
had adrenalin 4x4 arms on aparantly for a 4" lift which are 20mm longer than standard and they threw everything out, so now changed to sumo bars and all fine

Sorry to bring up an old thread but having the same problem. Although mine is ok with the front prop removed. With front prop in place i cant drive above 30mph as the vibration is so bad!
Would this mean that the uprated radius arms could be the wrong length? I brought it with the problem thinking it was just a worn UJ.

PM067 | Lightweight 3deg Castor Correction Radius Arms (pair) Yellow

These are the arms I have fitted. I have a 2" lift.

Arms are correct according to paddock spares. No play in diff or transferr box. Ive been told it could be a case of different ratio diff causing the problem??
I'm really confused now so any help would be much appreciated.

I had a similar issue when I lifted the nose of the rear diff. This was done by putting the rear radius arm bushed on the wrong side of the chassis (In my wisdome to gain 5mm less wheelbase or sumthing like that) Dont Ask!

The salisbury axle being a longer nose was lifted by not alot but the vibration was horrendus!!!! Adrenaline 4x4 arms well check they are the correct length I wouldn't mind betting its somthing along those lines

Doh Read Second Page!!!

All bushes look to be fitted correctly. I'm going to change the front diff the weekend and give everything a double check over. After that my only other option is transfer box. I really don't fancy that though!

Is prop shaft phasing an issue ? See the attached article that i found on another site. I dont know what landys have this issue.

Sounds like prop vibration.

sometimes when you fit a lift to a landrover you twist the axle forward a touch.

Your propshaft is designed to be at the same angle at the axle end and TB end. If they are not then you will get vibration. It dosent matter what angle the shaft itself is(so you could lift your fender 10" if you want, you would obviously need a longer shaft) but the joints must be parallel to each other.

A Double cardon jointed prop should solve the problem.

But its a lot of money if its not prop shaft vibration. I would suggest getting under your motor and see if you can see if there is a major difference in angle

Angles look fine after a quick check by eye. After speaking with the previouse owner he told me the rear axel is a 24 spline from a discovery and the front is standard 10 spline defender.
Could it be something to do with the diffs being different ratios??

Thanks for all the advice so far.