t-10 4 speed, had noise in 1st ,2nd ,3rd but not 4th gear??? pulled trans out, pulled side cover to find a few things,,at least 1 tooth from a gear and some of what looked like chunks of a thust washer??? i have rebuilt a few automatics but never any 4 speeds,,,are they hard to rebuild??/ any help or info would help.. thank-you very much....