advice please

[alanno123]

ok so i will try to explain this as good as possible but it might be a bit long sorry in advance
i bought this 1.9 tdi passat se 130 and it had many problems
but 1 i found at the beginning was the thrust bearing on the clutch was noisy but this went away after a little time and since the day i bought it it had a rattle coming from underneath the car some where (sounds like a plate ov metal as tho a bolt has came out slightly and its rattling about) i checked all the arms and suspension (usual places) but theres nothing lose it sound like its coming from either the wheels are actually under the car but not the engine bay at all
also when i drive the clutch bites really low with a thud but doesn't pull away until you release the whole way
but sometimes its like a normal clutch bite area
also it refuses to go into 4th it goes into the slot but when you release the clutch it just grinds like it hasn't engaged properly

iam thinking knackered dual mass flywheel and clutch
and possibly 4th gear synchromesh on the gearbox
or possibly both
whats your thought any help much appreciated before i go and pay what i payed for the car again on a new clutch and flywheel
also is there a how to on the clutch i have done 1 on a focus but i like to look at others who have done it for advice and what to look out for thanx