I have a 2005 Doblo1.9jtd Family. Yesterday I have had a failure somewhere between the engine and the wheels. The engine still runs and I can select any gear, however the gears won't engage. It was quite sudden although I thought there may have been a little clutch slip in the last few days. It didn't go with a bang, I just changed down at a junction and nothing happened when I went to pull off. I've just got a boxfull of neutrals.
I did smoke the clutch a little about a year ago when I got a caravan stuck but I had it checked out then and was told there was no damage.
So I guessing clutch, DMF, clutch cylinder, (hopefully not gearbox)
Before I decide which garage to get it towed to I could do with trying to narrow it down a bit. If anyone can give me a few pointers it would be most useful.

Diferential or the clutch is not engageing

There is a selector linkage that can fail, you might be lucky and it's that, do a search on the site to look for similar issues.

Check a drive shaft hasnt become unbolted, gears will engage and diff will spin power out the failed shaft.

It turned out to be the clutch. Completely worn out. Had the job done for £260 + VAT which was almost the cheapest quote I had (the cheapest couldn't do it till next week). The new clutch is made by LuK. I've looked on the web and apparently Ford and Nissan use them so I guess it's an OK make.
The one thing I was annoyed about was the recovery service. I've paid them about £150 a year for years and I've rarely had to use them. I broke down during the Christmas holiday period. There were no garages open so they towed me back home. When the garages were back open after Christmas I phoned them to tow me to a place of repair and they wanted to charge me £49. I spoke to their customer relations department but with no joy. As far as I am concerned I pay them to get me out of the brown stuff when I need them (so far three times in 17 years I think).
My annual subscription is due in August - I've politely asked them not to bother sending me a reminder.

It's standard that rescue services don't rescue you free of charge from your own home. Shame cos I wanted them to take me to Tescos and back the other day!

All I wanted them to do was live up to their promises. I've paid them well over £2000 during my membership. I pay them to do what's needed if I'm unfortunate enough to break down i.e. to get me safely home and my car to a place of repair. They did the first part but couldn't take me to a place of repair because nothing was open (neither their fault or mine). I don't think it is unreasonable to expect them to take me to a place of repair when one becomes available. I've called them out three times in seventeen years. Twice they had to tow me back (farthest was 2 miles) and once fixed the car at the roadside (which they charged me for the parts). They must have made a huge profit out of me over the years.
However because of this they have now lost a customer.