I have seen this all too often. The overdrive gearknob switch won't stay in place which is a real pain and of course means no overdrive.
I am going with a different approach though which is cheaper and whilst not as hands on as the above option should be fine with how I want to use the 2000, more of a cruiser than a sporting car.
Here is an overdive switch for a TR2 which I have used in the past on a Vitesse I owned. That's not the position for it by the way but was a good place to put it whilst I worked.
I then thought about using the location for the dimmr dwitch on the dashboard as the dashboard lights are rubbish anyway and there's no need to dim them!
Now started another saga where the car decided to fight me.
I pulled the dashboard out and removed the dimmer swicth which wasn't easy but when I fitted the overdrive pull switch it didn't really work well as a solution due to the gap around the switch. During removal of the dimmer swicth though the connectors became disconnected from the back of it so when I wanted to replace it I needed to use a spare I had.
I needed to get a little bit more clearance though and had to disconnect the tripmeter cable from the speedometer. When putting this back I actually found it was broken at the speedo end but I thought this wouldn't be a problem as I had a spare on the original 2000 speedo. The cable had actually broken with the plastic connections falling inside the speedo so the job became a bigger one.
OK I thought, I'll swap in the whole 2000 speedo but then realised it wouldn't match as it has chrome rings whilst all the other gauges have black rings because they are Pi ones. Then I remembered a brand new TC one I had bought as a Rimmer Bros clearance item a few years back. That had a black ring and the trip doesn't use a cable as it's a push button through the front of the gauge. I fitted this although it has a top speed of 120mph instead of 140mph but who's kidding anyone the car will ever see 140!.
With the dashboard back in I could return to fitting the overdrive pull switch.
I put it where I had in mind right from the start, where Triumph fitted a pull switch for a rear screen heater. This is fine as I can re-use the hole for a rear screen heater switch which I will need in the future.
So, a bit of drilling and fitting resulted in this.
A Triumph part in a correct location in the car.
Now what I need though is a gearknob for a non overdive 2000, maybe a complete gearlever too but that's for another day.