That's the problem my gearbox is only standard but it was freshly rebuilt before I put it in the car,I've only done about 2 or 3000 miles in the car so far and not really many hard miles,I've got a 2wd rear diff,I've got greens and t35 .48 but putting the .55 housing back on soon and then light blues and get it setup,it might help me a little bit that it's a mk4 escort estate shell so less weight so should help with less stress on the box lol I will try on central day and not bother with the reaction times,head gasket will be done by then aswell