A/T won't drive after swap

[R_custom]

Hi guys, I just finished swapping a 240sx KA24E into my 90 D21 2WD. I was gonna test drive it, but it felt like it had a huge slip in the Auto transmission. I put it in reverse and the truck will kind of roll backwards, but it won't do that in drive(both Drive and reverse are slipping, but its worst in drive). I know that the transmission works coz it was in the truck before. I am sure I installed the torque converter correctly. I am trying to figure out whats the problem, but I have no idea where to start. Any help would be great.

Thanks

[Rev_D21]

How's the transmission fluid level?

[R_custom]

Yes, Fluid level is good. Just took it out for a drive, Reverse is slipping but it seems to work a lot better than drive, Drive is slipping like hell and It won't shift.

[jdansmith]

Isn't that the trans the input shaft fell out of? Did you ever take it to a trans shop and if so did they re-install the shaft for you? I do not know much about how the auto trans works but I don't think the shaft would just fall out. Could be related , if you did receive help from a trans shop I would ask their opinion on your symptom. Good luck finding an answer.

[R_custom]

Actually,I took it to a trans shop and they fixed it for free. I didn't think the shaft would just fall out either, but actually it does. I was right next to the tech when he was working on it and he seems like he know what hes doing. I will sure give those guys a call. thanks

[longtooth]

If there isnt a huge puddle I would say the converter isnt fully seated onto the input shaft or there is a error with the input shaft.

[jdansmith]

^ I was thinking along the same lines.

[R_custom]

So, I finally got to work on it today and found the problem. I have to top the ATF off, drive it around for a little with the transmission slipping, then top it again, done it for like 3-4 times and it drives and shift like it was before.
Thanks for all the help guys