Join Date: Sep 2005
Location: Right Side O The Pennines
County: West Yorkshire
Re: 147 Gearbox
Okay, this is funky, same thing happened to me, about 3 months ago I had to have a new gearbox because of it, the 3rd gear syncro sleev was shot, this holds it in gear when selected.
Exactly the same problem as you guys are having, it started with a crunch going into 3rd then started popping out occasionally when applying hard acceleration then finally wouldn't stay in 3rd at all.
Unfortunately in my case I left it too long ad the particles of metal ended up grinding the bores that the selector shafts sit in a funny shape, hence the new gearbox (The casing is a light alloy, not sure what but felt very aluminiumy in weight and feel).
I urge anybody who has this problem with their 147 to get it fixed sooner rather than later to avoid a big bill (it's gonna be big anyway), but mine was £850 for a secondhand box and a new clutch fitted. If it was just the 3rd gear syncro and a gearbox strip down and rebuild it would have come in about £380 I think, but don't quote me and that is at independent prices not main dealer.
Hope this helps more than it shocks.
Nero Fuoco 147 Lusso - Bianco Nuvola 147 GTA - Carbonio Brera SV - Azzurro Le Mans GT 1600 Junior