With my truck I found that when I pulled the tranny (without the weight of the transmission as a counter balance) the engine tipped forward; not by much but it was enough. I spent two days trying to get the tranny on before I got the brainstorm to stick a little screw jack under the front of the engine and prop it up so that the trans and engine lined up. If they aren't parallel and centered you will never get that transmission on.

'89 P'up, 2.6 I-Tec, 488,000 miles and done... gone to the great beyond