Hi everyone.Im new here and have a Daf 50 series 1999 reg t78 abk with a 6 speed gearbox that needs replacing.180 engine. I have had it from new and would quite like to replace the gearbox because it jumps out of gears and is not easy changing down. Any ideas on the way forward? Good second hand one would be fantastic at the right price. Any thoughts would be appreciated. John
Hi mate, before you buy a new box, have you checked these?
FAQ’s for Common gearbox faults
Problem - jumping out of gear (the gear lever moves from its engaged position).
Here are some things you could check:
Remove linkage from gearbox and select gear manually. If the gearbox remains in gear, check the following:
Are linkages, tie bars and ball joints worn. Are they free from any obstruction?
Are the gaiters intact — debris from worn gaiters can jam the linkage.
Are the cab or engine mounts worn? Cab/engine movement can jam the linkage and stop it moving freely.
If the gearbox has been removed, has it been reinstalled to its original settings?
If fitted, are linkage dampers or springs worn or broken? Worn or broken dampers can allow excessive movement of the gear stick causing a jump-out situation.
If fitted, are external detent plungers and springs worn or damaged and are they set correctly?
Look up commercial vehicle dismantlers (scrapyards) on line or yellow pages in your area.
A scrappy might be your best bet (or eBay) but the problem sounds like worn selector rods to me ( not sure what gearbox it is and I’m not an expert)
They may have been all exported as it’s getting on a bit 
What area of the country are you in ?
From memory the DAF 45 and 55 had a 5 speed ZF S5 42. However the ZF S6 36 may well have been an option.
Try asking tnuk Norb