Engine vibration

[Oldsschool79]

Hello everyone, looking for some help with an engine vibration between 2300 - 2600 RPM.  The vibration is present in neutral and park. It is high amplitude at crankshaft speed.  I tried unbolting the convertor and running the engine, the vibration is gone. If I bolt it back, you guessed it, harsh vibration. The torque convertor is a Jegs model 2200 stall and it did not look like it needed shims. Fell right on the specs. I tried phasing it with no luck but it does seem to change. The transmission is a TH350 that was completely rebuilt with clutches and seal. There is also a new damper and flex plate. All the diagnostics are pointing to the convertor which I replaced twice with the same brand. Any help is always appreciated. Thank you in advance.

[SoupMan]

The vibration goes away in drive and reverse?

When you first installed the converter, did you make sure to get the converter all the way in? If I recall there's like 3 steps before it's fully engage. You have to spin it click, click and click. Someone here who's done it more often may be more useful with regards to that.

Did you inspect the input shaft. If the torque converter was not installed properly the first time it would have caused damage.

Make sure fluid levels are good although I doubt that will be the cause of your vibration.

[Oldsschool79]

Problem solved! So I replaced the trans mount. It absorbed the vibration and reduced it. I wasn't happy as it seemed to be masking what was going on. I pulled the convertor, inspected everything and found nothing worn or broken. Reassembled it and phased the convertor turning it several times on the face plate as I have done in the past. It finally worked. The only thing I can think of is the convertor hub was getting hung up in the crank.
Thanks for the feedback and I hope this helps others.