I have been getting a clunk sound when I shift from 2nd to 1st (mainly downshifting) but I also get it from drive to reverse and park to reverse. I have a th350 with 3500 stall. Trans is new and I also have a new rear end rebuild (Posi,ring/pinion axles etc) I also put in new hotchkis springs bushings/shackles). I just did a BB rebuild so basically everything is new. I did not get this sound after the rear was done or when the trans was new. It seems like it's been getting worse since I added the 430hp motor rebuild. Any ideas?