I had my transmission rebuilt 4L60 and a new OEM torque convertor replaced. Now my truck vibrates when it is idling. It also makes a noise like a rattle coming from under the truck it seems. Basicly noise is heard when vibration is taking place. What could this be? I would like to have some knowledge before I take it back to the shop. Any ideas? It is a 91 Silverado and I had no transmission problems except for the oil pump was going out making a noise off and on and the pressure test showed it was weak. No vibration before the rebuild and torque swap though.

 

Have them unbolt the converter spin one position then bolt it back . Ussually a good bet of a vib not really because of the position but many installers are bad to use the converter bolts to pull the converter forward which will resultin vibration and sometimes noise

 

So spinning it do they have to take the trans. loose or just unbolt the convertor from the flywheel. How hard is this to do? This is a well known company that did the work but when I drove off and hit the first light I felt and heard the noise, vibration. It is annoying. I plan on taking it back to have this checked out soon and I wanted some knowledge to speak with them. What happens if they do this and it is still there? Do you just keep trying to turn it until you find a spot where it doesn't vibrate. The noise is like a rattle coming from that area. I don't know why they didn't hear it and feel it before I came and got it. Thanks.