A while back I had to replace the engine in my truck. After I got the new engine put in I had no problems whatsoever with the transmission. I just had to put another engine in it recently but this time this thing is throwing a few different codes. First there was an p0356 which is gone now.

Then it threw some other code that gave some explanation that it could be taken care of by disconnecting the battery and holding the two battery cable ends together for a few seconds and then driving the truck after 5 minutes to reset the transmission or something like that.

Well, that code is gone. But now it is showing p0700. It's saying that the vehicles transmission control has a malfunction or something like that. The fluid level is fine.

But I don't know what else it could be since it didn't do anything like this after I put the first engine in. I'm at a loss.

 

Usually there is a second code with the P0700.... if not immediately, then soon thereafter...

 

Check you wiring, could be crunched/broken/disconnected during engine rnr.