Quick question to anyone who might have had experience working on driveline/ manual transmissions. I'm new to the Mustang world and rear wheel drive cars in general. I'm a reformed FWD ricer :bigthumbsup. I bought a 5spd 2002 Gt and love it! I've always done what I could as far as repairs and mods myself but my experience with rear wheel trannys is nil. I decided to upgrade my steel drive shaft with an FRPP aluminum piece. I did the install myself using the haynes manual and stuff I found online. I broke the four 12mm bolts that mount the shaft to the companion flange of the rear with a 12 point box end with some pretty heavy blows to the wrench handle with a regular metal hammer. The wheels were set on ramps, the parking brake was set and the tranny was in first. Now I have what sounds like a whistling sound coming from the trans in all gears. When I press the clutch in while I'm moving the sound disappears. Soooo long story short. Did I possibly damage my tranny (output shaft or bearing maybe) with the shock of the hammer blows? Any input would be appreciated. Sorry for the long winded post.