I have noticed the usual clunk does not happen when going backwards,
and I have just got stuck reversing out of a snowy drive !
What should i check first and what are the common probs ?
88 mk2 golf.
Only eats snow going forwards[xx(]
Check your under bonnet vacuum lines, esp the Light green one that disappears under the front left wing & your reversing light switch.
I had the prob before but just turned out to be the reversing light fuse.
Is there a way of checking the system buy putting the car in reverse and looking to see if the diaphram has moved or does this only operate when the wheel are actually turning ?
What colour wires shoud i check in the revsing switch ?
Q) Is there a way of checking the system buy putting the car in reverse and looking to see if the diaphram has moved
A) yes you can check it that way but the engine has to be running to create the vacuum,
you might also want to check your vacuum non return valve (fitted ubder the bonnet between the inlet manifold & the green vacuum pipe)
Q) What colour wires shoud i check in the revsing switch ?
A) good question, all of them I would think!
btw, the gearbox mounted Syncro reversing light switch was dropped withour replacement on 01-06-2007 and is no longer available from VW,
but I have some rebuilt ones here (rebuilt with new springs, conntacts etc) which are for sale on an exchange basis at 50 eu each + postage
If it looks like the switch is at fault i may need one from you!
I managed to pull the head of an EV engine last night so hopefully it will recondition ok.
Looks like ive got a busy weekend 
Or I will rebuild your switch with new pins/springs etc for the same price.
i noticed that 4wd didnt engage while reversing in snow with my car too.
is that meant to be normal??
The reverse Rear wheel drive normally engages within about 3 to 6 feet or so of driving backwards, usually you will hear (and possibly feel) a bonk from the rear end, this is the freewheel mech being locked out and the reverse rear wheel drive engaging.
Given the age of the reversing light switch and the fact that they operate every time you change gear (not just into reverse) it is usually this which is faulty, followed by the exposed vacuum pipes & wiring mounted on the rear diff,
There is also a relay mounted on the fuse/relay box P/N 191 957 917A it is mounted either in position 18 or 20
Just a thought,
If the free wheel isn’t working in reverse would it be possible to wire up the rear diff with a switch , so if you need 4wd going backwards you push the switch and power goes to the solenoid on the diff to engage drive.
This may be a bodge but if the electrics are realy bad would this be a solution to the problem by being able to operate the diff manualy ?
Thanks a lot for the replies. Much appreciated, will give it a shot!
Problem fixed 
Blocked vac pipe, the green one !
Wow, I was just about to post a thread asking about that clunk while reversing. I’m glad it’s normal. I can relax now.
Also glad to know that you know how to rebuild the reverse switch, since I’ve noticed that it’s waaaaay different from any other 020 Reverse switch.
Hi Folks…I’ve got a similar problem. The reverse lights didn’t work and I had no 4×4 in reverse.
I took the switch apart and fixed it so the reverse lights come on now…I made sure all the other connections inside the switch were working properly too, so I know that’s not the issue.
I’ve given the light green pipes a BJ and they all seem to be passing air, so they’re not blocked. The 4×4 does engage in reverse, but only 1 in 10 times…and usually not in the snow when I need it most
have you checked the relay which is located in the centre console?
take off the console, find the relay, and check if it ticks when you select reverse and ticks of again when you put it in first
You might also check the 2 electrical connections on the rear diff