I've fitted the overdrive that came with the scrap SIII today. Only been out once so far with it on a test run, but it seems to be a good'um.
Overdrive 4th is very nice and quiet, with the engine runing much slower, but I had to drop out of overdrive for anything more than slight up hill.
Moron of the day award - guess who should have bought a new speedo cable and fitted it first...? Looks like I've just created one of the nastier little LR jobs for myself...
As I type
9 years ago