Quote: Originally Posted by RB30-POWER Back onto this hard casing issue. I think the reason, it wears/fails is due to excessive heat inside the gearbox. The R33 boxes take around 4L total, compared to the 2.4 of the MX7. 2.4L will get hot very quickly inside a high hp engine and break down quickly. Especially on BT1 chaser vehicles. I think if Nissan/Holden said change oil every 12months, the MX7 boxes would have faired a little better in age. Tempest, was your box noisy at all, before it failed? Or was it a dead quiet smooth box? was noisy, but not excessively. had a dog-gear whine to it through first and 2nd. oil was 2-3000km oil, change it regulary. there appears to be some heat damage to the gears from what i can see, so could very well explain it. see what the experts say when i take it there.

I still can't understand how people break MX7 gearboxes. I was drag racing with mine nearly every weekend when I lived in WA, had 193rwks, (ok so not as much as the 250 yours had) and up until it was stolen I had done 126 passes without a problem what so ever.

mines probably done 60passes, only 3 or 4 on slicks, but cops worse most sat nights...

193-250 is a pretty big difference, add to that the huge torque that both Tempests and Nitrons car would be making with their setups and I guess they really are pushing the boundaries...and may have found the limit it would appear. Didnt have any issues with mine when it was manual and making 243rwkw apart from frying a clutch..then again mine wasnt really a manual for that long...I got sick of gettin toasted by basically stock autos VLTs off every set of lights....

I can't believe it broke. It never got shifted hard or fast so whats the deal??? At least second didn't break- that was my last effort in the car. Some original photos have not been recovered yet.