wobbly under load at around 45mph

[Jaspermowatt]

Right, another question. I've tried searching however I am pretty useless at being concise so have failed to type something in that brings up results that offer answers.
So when I hit around 45mph I feel a kind of wobble.
1) wobble is coming from the midsection, i.e it isn't coming up through the steering wheels so pretty sure it's no wheel balancing/tracking related (could be wrong)
2)wobble goes if I push through said wobble at around 55mph
3) wobble disappears when clutch is engaged
4) happens in 4th and 5th gear
5) wobble lessens if I take foot off accelerator
6) no obvious noise that worries me
7) may be irrelevant, but when idling sometimes i feel the landy shake but if i press the clutch it goes
8) happens, up hill or downhill or on the flat

It's a 1987 land rover 90, has 19J and lt77 and.

My only guess at the moment is an imbalance with something like the fly wheel so at around 45mph it begins to resonate.
other than that, haven't a clue. I'd like to be able to sort it though so any help i'll be grateful
cheers
Jasper

 

[nobber]

What are all your mounts like?

 

[Jaspermowatt]

What are all your mounts like?

All are new

 

[vilguy]

mine had this the other week and it was the panhard rod. Check yer bushes and bolts are toit as a toiger

 

[Dippypud]

What are all your mounts like?

All are new

Gearbox as well as engine ?

 

[vilguy]

Id suggest the wobbles are 2 seperate issues, mounts (i replaced mine which stopped vibration at idle) and a bush for the 45 - 55 mph stuff. When you depress the clutch at this speed you are removing drive... slowing down which will dampen the wobble.

Exact same issue as mine had. Mine got catastrophically worse a few weeks later as it elongated the hole on the axle.

 

[Jaspermowatt]

Id suggest the wobbles are 2 seperate issues, mounts (i replaced mine which stopped vibration at idle) and a bush for the 45 - 55 mph stuff. When you depress the clutch at this speed you are removing drive... slowing down which will dampen the wobble.

Exact same issue as mine had. Mine got catastrophically worse a few weeks later as it elongated the hole on the axle.

I've polybushed everything or are you thinking a different bush?
I'll recheck the mounts on both engine and gearbox.

Thanks again

 

[james6546]

I guess you have checked the UJ's. I had a wobble at 50mph and it was one of those on the way out.

 

[vilguy]

I've polybushed everything or are you thinking a different bush?

doesnt mean one isnt worn

Main one I would check is the bushes on the Panhard rod, and make sure the holes on the bracket on the axle havent turned into ellipsoids like mine had.

 

[Jaspermowatt]

I guess you have checked the UJ's. I had a wobble at 50mph and it was one of those on the way out.

To be honest, I'd not thought about those. I didn't touch them during the rebuild since they felt okay however replace them for piece of mind...

doesnt mean one isnt worn

Main one I would check is the bushes on the Panhard rod, and make sure the holes on the bracket on the axle havent turned into ellipsoids like mine had.

I'll check but since i've only done about 80 miles since fitting I doubt (hope) the problem lies there

 

[top drive]

you have gone round and checked all your bolts are right tight on the radius arms/panhard/traling arms yeah ?

polybushing in particular can mean you need to nark the bolt tight to get a good clamp on the middle tube of the bush or the whole bush can be moving about in there.

I had a bad vibration and a knocking.

Twas the prop shafts.

6 months later i had death wobble. it was the rear trailing arm bushes....

 

[vilguy]

get your mrs to wobble the steering left and right whilst your underneath it and that will highlight any problems if its related to the front end.

 

[chris mcc]

Death wobble for me was a fooked PAS box (up and down play in shaft).

 

[Jaspermowatt]

Right so got an update.
I've been under and there is a small amount of play at both ends of the front prop. However I noticed something else that worried me a little more. The front flange coming out the transferbox has play in it - as in, if I hold the front prop and wiggle it, there is a bit of movement on the flange that comes out the tranferbox.
I am really hoping that it is supposed to do that otherwise it is screaming money and time at me...

 

[nobber]

Right so got an update.
I've been under and there is a small amount of play at both ends of the front prop. However I noticed something else that worried me a little more. The front flange coming out the transferbox has play in it - as in, if I hold the front prop and wiggle it, there is a bit of movement on the flange that comes out the tranferbox.
I am really hoping that it is supposed to do that otherwise it is screaming money and time at me...

You mean play when you twist it in the rotation of the prop (back lash) or play when you move it up/down or side to side?

 

[Jaspermowatt]

You mean play when you twist it in the rotation of the prop (back lash) or play when you move it up/down or side to side?

They play in the prop is up and down, side to side.
The play in the transfer box is multi-dimensional.

 

[cornish rattler]

They play in the prop is up and down, side to side.
The play in the transfer box is multi-dimensional.

The flange just may need tightening up

 

[Marmaduke]

Disconnect the prop and take it for a spin with the diff lock on and see if it's still there

 

[Jaspermowatt]

Disconnect the prop and take it for a spin with the diff lock on and see if it's still there

Okay I shall do that. will it be okay to go fast? Just thought that it is bad to be in diff lock at high speeds cause of wind up or does that only apply if both props are connected?
Also will I have to do the whole, reverse at the end to unwind or does that only apply when both props are on?
Sorry for my nievity but i wanna be sure I am not going to screw anything else up.
Thanks

 

[Jaspermowatt]

The flange just may need tightening up

The movement is coming from inside the transfer box so not sure how I'd tighten it without taking the box apart?