Your best to get a cooler fitted for one,next thing is some tuners can also kill the box itself, not every tuner can make these boxes last very long, also take it to a trans shop that has done quite a few of them. Search the forum or ask people that have had 4 speeds rebuilt. Bayswater transmissions and Yarra Valley are the only 2 you can use with confidence in Melbourne. Mines still going after 5 years, only broke the planateries middle of the last year and it was a $600 fix with parts and labour, nothing else was replaced as its still in great condition.