You don't want to change the T2 chassis transmission ratio which is 1.7 What you do want to change is the overall gear/drive/rollout ratio. You do this by changing the pinion and/or the spur gear. The pinion is the normal change and on the T2 9comapred with T1) changing the spur gear is a pain - but it does help you fine tune the ratios.
Not sure I agree with the previous post entirely, being semantic. The wrong overall gear ratio will overheat the engine, whether you are overgeared or I think (never experienced it) undergeared. You just dont change the pulleys to sort this.
The Schottky is a good point though (if your ESC needs one). I don't know how, if at all, you can test a schottky. My car has been running hot the last two meets and I suspect strongly that the schottky has gone as the gearing is right.
Find out what overall gearing ratio your club members use on your track and if you are close (say within .2 or .3, maybe a bit more) then it could well be the Schottky.
You will find a ratio calculator equation on the net somewehere - I am at work and dont have it in front of me. You need your spur gear teeth, your pinion teeth and the chassis ratio which for the T2 will either be 1.7 or I believe early T2s had the T1 2.125 ratio. If you are not sure take out the rear diff and look at the pully wheel and pull off the dust covers (cannot recall if you have to dismatle the diff to do this (easy)). If it is marked 34 then you have 1.7. I am 99.5% certain that if it is marked 32 then you have 2.125.