AO Platinum Member
Join Date: Aug 2003
Location: London, England
I had similar on my old Sud back in 1994.... (a VERY long time ago...!).
What had happened was that a selector fork had moved and when in its detent hadn't pushed the 3rd gear fully in.
You could push the lever further and get the gear and it would stay in until you lifted off the throttle, at which point it would pop out again....
On a Sud it was quite an easy fix as their gearboxes had a removable sump plate.
Not quite so easy on a modern FWD box though... unless it is similar to the TS box 4th gear issue.
Audi TT 3.2v6 DSG
xAlfa 156 Selespeed sp3 + Brembo conversion
Fiat Cinquecento 899cc