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Changing 3rd gear syncromesh??

  In between cars....
Hi all

3rd gear syncromesh is getting kind of rough

How easy is it to change and all what bits would i need?

How hard is pulling a box apart?

try changing the lube first with some of the recommended grade, unless of course you have already done that? What mileage is it?
  In between cars....
70k mate, it most definately not the box oil, rest of the gears feel fine, but down shifting to third is kind of nasty, defo needs some attention or a new box
  PH1 172 Sport
If you havn't changed the oil its worth doing as it solved my box problems (same symtoms). Your looking at quite allot of money for a rebuilt box.
Its similar drain process to doing the engine oil, if you do a search you will find loads of info. Like caister says deffo worth doing if you havnt already, believe the correct grade is 75-80 and the box takes just over 3 litres but if you search you should find all this easy peasy.
  In between cars....
Found a thread in the how to section, 8mm square bolt on bottom, plasticy type wing nut on top of box

Will get a washer and oil ordered tomorrow, give it a go when i get a chance
yeah what he said, anything of the right grade will be fine just get the one thats most convinient/cheapest/whatever for you.
  In between cars....
castrol gpx 75/80 seems to be a winner after a quick search around?

Do you really think its going to make any difference? Why would it?
  BMW M135i
Splitting a box changing the syncro and sticking it all back together properly (the hard part) is a very complex job so unless you've done it before/very experienced mechanically i'd just chuck a new box on.

You'll be faced with this:

And the shafts have to be removed and built up on the bellhousing section of the box casing to get the detents in order to get the halves back together then get the internal part of the selector in the right place pretty much blind.

I was only changing the input shaft seal/bearing a syncro renewal is more fun as the shafts will need to be broken down, if and your doing one you might as well do them all imo.
  M235i / 172
Mine was ok untill i changed the oil, its got the castrol 75 - 80 in as mentioned above, the correct amount (untill it dribbles out of the level plug) but now it crunches in third, it doesnt really have to be a fast shift either! Duno what to do really, its new oil!
Gearbox specialist round here will strip the box and refurb it for 400 which includes labour and oil, but you have too source the parts
  audi a6 3.0tdi
originally mine was doing this but when i changed the drive shafts, engine/ gearbox mounts i did the gearbox oil as well. when it was all back together the shifting into third was fine. i actually presumed it was the mounts that solved the problem but it may have been changing the gear box oil.