Not sure if backlash is the correct word but how can I determine if it is the gearbox that's causing problems and if so what can I do about it.

If I grab the front prop it has a fair amount of backlash, I know this isn't coming from the diff as its a second hand one that I put on recently and I haven't had any problems with it. With the front prop off I can grab hold of the flange on front of the gearbox that it bolts onto and can turn this a fair bit. When taking up drive I can feel and hear the clunk from it. All UJ's are fine so its definitely not them.

Is there any way I can check for wear within the gearbox? I haven't a clue when it comes to stripping it. Also not sure if its worth noting that the rear prop is perfect with no excessive play or backlash so I'm assuming the transfer box is also fine.

A few things:

remember the rear prop has the hand brake drum on. If you're checking for play, then if the hand brake is on, it won't move.

Have you checked the rear A frame balljoint for play? Can cause knocking when taking up drive.

A frame balljoints fine for now, its definitely coming from the front prop.

And yup I remembered the handbrake

As far as I know there should never be any backlash in the actual gearbox - all the gears are in constant mesh and everything gets well oiled, if oil level is neglected then you'll soon know about it when trying to change gear before any wear occurs to the gears.

Rear prop - did you take the handbrake off? Handbrake holds the rear prop so it won't move if you feel it with it still on!

As for the play in propshafts then quite a bit is often normal, when feeling the propshafts you are feeling the play in the axles because the diff in the transfer box will keep rotating. To feel the play in the transfer box you can remove the propshafts from the box then feel the flanges - turn them both together in the same direction and you should feel the play in the whole box. Always play, usually not enough to worry about mine clunks a bit if too rough and it's had a reconditioned gearbox a year ago and I've just put in a new transfer box from a 300 Disco.

Have you checked the mainshaft? Remove the inspection plate on the back of the transfer box (up and to the left of the handbrake drum, looking forwards) and you will see the end of the mainshaft and the input gear that surrounds it, chock wheels and release handbrake then rotate the handbrake drum to see the play between them. Common problem with LT77 and early R380s also I think due to oil starvation - can fit a cross drilled input gear to prevent any further wear if it is not too significant already.

Splines on my mainshaft were almost completely gone when I looked, thus the rebuilt gearbox.

Edit: If you remembered the handbrake - are you sure its not binding? Can cause all sorts of clunks if they do.

Handbrakes not binding and yeah the handbrake was definitely off when I checked the rear prop so I know there's no problem there. As I said movement on the rear is minimal which is good.
As for the front, even with the prop off if I grab the flange on the front of the gearbox it can rotate a fair bit, maybe about 1/6th or so (I'm no good with fractions), but I can basically replicate the clunk exactly as it happens.

If I checked the mainshaft for wear could that possibly be the cause of it? Gearbox oil is very recently changed as well as adding molyslip. Transfer box was topped up so the oils haven't been neglected.

i am investigating the same thing on mine,

here is my thread

http://www.landyzone.co.uk/lz/f7/lt77-lt230-checking-spline-wear-226279.html

If the lt230 is a suffix b then they were known to cause issues with gearbox output spline and an oil kit to increase lubrication was suggested.

Suffix c onwards you can fit a cross drilled gear and the gears are wider.

I believe that 300 tdi and td5 transfer boxes are a different gear.

Ashcrofts should be able to supply a cross drilled transfer box input gear.

Where can I find the suffix?

the_wolf said:

Where can I find the suffix?

Click to expand...

Below the filler plug next to the ratio sticker usually, for very early boxes it can be found on the side of the box to the left of the fill plug.