2004 WJ 4.0 Automatic. I'm putting in a new-to-me engine. Everything has gone pretty smooth so far, until the re-install.

On Saturday, we dropped in the new engine, lined up the bell housing, threaded the 4 main bell housing bolts, bolted the engine to the engine mounts, and then torqued down the bell housing bolts -- in that order.

But when I went to turn the engine so I could bolt the flexplate to the torque converter, I found that it was bound up. I reached in the starter hole and tried to turn the torque converter, and found it wouldn't spin. I have put in transmissions before and I know that IF the torque converter is not seated all the way, it would bind and could even end up cracking the pump. I didn't remove the torque converter when I pulled the engine, so I assumed it remained seated and I didn't mess with it... But now I wonder if somehow when I removed the engine I could have unknowingly pulled the torque converter forward. SO I decided to pull the tranny back and see what is up.

I first loosened all of the bell housing bolts, so that the engine and tranny were separated about 1/2". I found that the engine could turn now, however, the torque converter was still stuck. So I put a tranny lift under the tranny, undid the the drivelines and crossmember and pulled the tranny back about 2 1/2". I can now turn the torque converter freely, but it sure seems to be set all the way back in the bell housing. I cant even fit my pinky finger between the back of the torque converter and the inside of the bell housing. Furthermore, it appears that the gap between the front of the torque converter and the flexplate is larger than the gap between the bell housing and the block; like with the bell housing and the block bolted together, the torque converter still wouldn't meet the flexplate. So my question is, is there anything else that can cause binding like that, IF the torque converter is all the way seated after all?

I hoped to keep everything lined up, and not have to fully drop the tranny yet, but today, I think I will... So I can inspect the flexplate and take the torque converter out to check the front pump, and make absolutely sure it is seated all the way. Anything else I should check? any possibility the flexplate is bent or something? Geez I wish I knew more.

 

Did you check to see if there is clearance in the crankshaft pilot hole? In other words, is there a bushing in the crankshaft that won't allow the hub of the torque converter to fit? I'm thinking standard transmission pilot bushing, but I've heard of other engines having different bushings also. Which flexplate are you using, your original or the new one?

What's your new engine out of?

 

I just double checked and measured. It's the same. I'm using the original flex plate. Other good news is that the pump isn't cracked. Phew! I'll reinstall the torque converter tomorrow and try bolting it up again. I'll keep checking the tc as I tighten the bell housing bolts down. Any other advice?

 

Before you install it, check the dimension from the block flange to the back of the flexplate. There should be LESS distance from the trans flange to the front of the torque converter mounting bosses. When everything is bolted up, the converter should have to move forward to bolt tight to the flexplate. On GM cars, it's about 1/4 to 3/8 of an inch.

If the engine was left standing on the flexplate, it could be bent. That will show up by a difference in the gap between the plate and the converter's mounting bosses.

 

It wasn't sitting on the flexplate. Just to make sure, I pulled it and checked to see if it was bent. It sits flat on the floor... So I think its not bent. I'm betting the torque converter wasn't set all the way in. I'm not going to have time to work on it again until Wednesday, so I'll update then.