The car is a 1989 240SX with a CA18DET engine. I pulled the original transmission out and drained it. Most of the fluid came out black with a nice shiny metallic swirl to it. Since it had apparently already been rebuilt once, I have to assume it's shot at this point, though one can never say never. I'm sure that given the right motivation it could be rebuilt. I've rebuilt a lot of engines, and a lot of manual gear boxes, but I've never tried an automatic and would prefer not to start with this one.
He obtained a used RE401A transmission, and I started to do the swap. The first thing is that the bellhousing was different, which I assumed was either due to the SR20DET engine, or the fact that the transmission came from I believe a 1991 car. Regardless, the harnesses swapped over fine, as did the bellhousing. The torque converter on the 240 is a three bolt converter, while this used transmission had a four bolt torque converter and flex plate. Again, I assumed that this was because it was from another car, which I believe he said was a Maxima (but I doubt it since that doesn't make sense) but it IS a RE401A, and used the 240 torque converter, which I checked to ensure that it would mate with the transmission properly and slide down onto the pump input shaft and mate with the notches on the input shaft.
The issue I'm having now is simple, and not uncommon but given all the things that have changed I'm a little more concerned than normal...
The transmission and the engine won't completely mate. There is a 3/4 inch gap between the engine and the transmission. If you try to pull them together with the bell housing bolts, the engine binds and won't turn with a breaker bar. The trans is bolted up to the back mounts, and if you don't force the engine and transmission together, the engine will turn both the flex plate and the torque converter, however the torque converter bolts are not in yet.
On a lot of cars this tends to be an issue where the torque converter hasn't seated fully into the transmission, and turning the engine by hand will usually solve the problem if there is a little pressure on the torque converter from the flex plate. In this case, there isn't a change and you can fully rotate the engine without it dropping into place - assuming that is the problem.
Is it possible that the input shaft is longer on the later transmission, or will I need to drop the trans again and make sure that the torque converter is seated properly. Normally you can spin the flex plate with the crank bolt, and it will spin the torque converter (which it does) and the converter will drop into place with minimal fuss. It acts like the flex plate isn't mated properly with the torque converter, or the converter is too far out. Either way, it's not going together and after about 26 hours of fighting with this car pulling the old transmission out and swapping the new one, I'm beginning to get stumped.
I'm not getting paid to do this swap, nor do I want to be, and I certainly don't want to tell the kid that I can't fix it either. He can't afford to have it fixed otherwise, and without it, he will not have a car - period - which is sort of bad for a freshman in college.
Any suggestions that anyone can offer would be greatly appreciated. If I need to pull this thing out again I will, but I'm obviously not looking forward to it. It wasn't pleasant getting this one in...
Thanks,
Dave
