P2 Differential noise

[RobHomewood]

In December I had my P2 differential rebuilt by a Land Rover specialist and refitted by the local Land Rover garage. I drove her home only a few miles and put her up on axle stands for the rest of the winter. When I run the engine up to temperature in situ I usually put the engine gently through all the gears at tickover speed to keep everything moving and coated in oil etc. However I am getting some quite alarming clonks and vibrations in 3rd and 4th gear which even out if I pick the speed up (both wheels turning). I havent investigated closely yet nor got fully underneath - its a bit cold at present!
Is this noise/vibration perhaps what you might expect because the drive is under no pressure and at low revs or could the drive shaft be misaligned somehow or some other defect? Your thoughts would be appreciated.

[jefflee]

Don't panic Rob, yes it dose sound awful when its in the air as there's a lot of free movement with no load,
My P2 is exactly the same but on the road its sweet as a nut.
PS. I'm a firm believer in gearing up diffs on p2s, ( usually 4.3 for 4cyl. and 3.9 for 6cyl )
I've done all three of mine, it makes them much better for modern driving.
cheers Jeff.

[RobHomewood]

Thanks Jeff, that is very reassuring.
I did toy with the idea of upping the diff ratio (currently 4.7) as there was a tempting choice of exchange units available but in the end there was little wrong with my original apart from bearings (and I am not sure Ashtons wanted to take my 1947 unit as the case is slightly longer than standard LandRover) so I took the easier choice to keep it 'original'. By the way there is an excellent Utube of the general rebuilding process on the Ashtons Transmissions website which is what sold them to me.
http://www.ashcroft-transmissions.co.uk ... diffs.html

[apkok]

On the subject of differentials, my 1947 16 came with a spare diff. I'm hoping it's the recommended higher ratio type. Should there be any markings on the casing to indicate the ratio? It would be a bit annoying if I replaced the existing diff with one of the same ratio.

[luli]

If the differential is not installed, you can count the number of teeth on the crown and the pinion and take the ratio. For instance, in my 10 the pinion has 9 teeth and the crown has 44 teeth, so that the ratio is 4.88.
On another issue, if the drive shaft is not ballanced, noise as described above can happen.

[apkok]

Thanks Luli.

[chris dancey]

In agreement with Luli, the possibility of an out of balance propshaft can cause this, also check to see if the prop shaft universal joint knuckles line up, if not this can cause an out of balance situation.