Thanks a million for your advice I really appreciate it. I let you know how I get on soon. Cheers Sammy.
Who is Alex ?If you have to replace that gear, consider changing to the upgraded one used by the 1130s. It gears the starter motor lower so that it spins faster for the same crank speed. It reduces the power drawn by the starter and hence current, which means lower voltage drop on the supply cables. Ask Alex about it. Pretty sure he'll advise you go that way.
Errrm, well, kind of!!!That means I am already getting the new part according to the part number correct?
My TNT is 2010 so its ok it had already the newer z67 and I ordered of the correct catalogue which is 2010 !You DO need the T60 gear to work with the Z67/17. The original was 58 was it not? I can't remember, but it stands to reason that if the gear driving the sprag clutch gets smaller, the driven gear must get larger. My link above has the part numbers for the gears required for the upgrade, as specified by JohnnyO in 2006.