Hi everyone I have posted recently about the same car that I have had issues with and is probably part of all my issues.I recently had 373 gears installed,about 400 miles ago.I have been taking it really easy on the car driving like everyone's grandmother.When my mechanic installed the gears I had the differential completely rebuilt.I even got brand new spider gears from ford.The are the actual ford spider gears old new stock they call it.Right from ford.I have been noticing for a little while that when you are at a stop sign when I put it into first gear before the clutch is let out, it will clunk.I hope this isn't a sign of a bad install? Things seem maybe a little sloppy under the car.Drive train slop.It seems to be clunking more and more lately as I am going down the road shifting through each gear. Mechanic says the gears turned out perfect everything is where it should be for tolerance.If this was the case it seems that I wouldn't have started to have these issues.I am trying to solve these issues step by step because he has done other work and some things are starting to unfold.He installed a mcleod clutch and flywheel which as after that I started having knocking and some shaking coming from tranny area. He's normally good but apparently he doesn't know mustangs that well.Does my clunking sound like a bad gear job or a bad motor mount,or a tranny mount.This is getting really expensive.