300 tdi transfer box gear

hi peeps,im after a bit of help again,im getting a thudding when i take up drive,i know this is the main transfer box gear that goes on the back of the gearbox main shaft,can the gear be replaced or does it also knacker the splines on the shaft,there is a lot of play when handbrakes on more than usual,just trying not to have the box ripped apart if possible.
thanks
richard.
p.s.ive also just noticed my inner wing in the engine bay is rotton,i know it needs replacing but is this an mot failure the rot is from the bottom where all thewiring loom sits.
thanks again
richard

£45 for a cross drilled input gear cluster..

is this all it will need then,and are they all the same or will i have to take the old one out and count the teeth

any ideas on the inner wing for mot mate

redhand said:

£45 for a cross drilled input gear cluster..

Click to expand...

intermediate is the only gear cluster as is 3 in 1

ftc5089 is 26 tooth input gear and ftc5087 is 28 tooth input gear ,gear box splines wear as well if input gear is worn mainshaft will be too ,fitting new gear on half worn splines will reduce clunk but wont last any longer ,inner wing will be a failure if rust is within 30cm of mount or important component ,often fail if rusty near brake servo even though its fastened to bulk head,if you have a disco 1 you need to be able to weld

jamesmartin said:

intermediate is the only gear cluster as is 3 in 1

Click to expand...

this is for jamesmartin.
hi can this be changed on its own or do i need to do the gearbox aswell,
also any ideas on the inner wing for the mot
thanks
richard

i can weld but i refuse to pay for the yearly fee for the gas.and the pub gas is crap the weld is too cold,ive already had the rear cross member hangers,both sills,n/s/r wheel arch and front body mounts done,its doing my head in now im just constantly chasing the rot.the inner wing rot is in around the middle just behind the airbox theres a whole about 2inch long by and inch toward the engine

sorry its also the near side front/passenger side

never tried with co2 ,i know what you mean my own disco 1 i built out of bits 10 years ago ,is off the road now replaced with a disco 2 i swapped a lightwieght for as is rotten in same places ,most of underneath and foot wells inner wings etc shame ,id puddle weld patches on easier and looks well after going round eges with seam sealer