Wife's line car, '87 245 has developed whine in 1st, 2nd, 3rd and 5th, no noise in 4th. I assume this is from the layshaft bearings. All other functions are good. Question is whether to attempt changeout myself or take tranny to shop for work. Prolly 200-250K on it. No previous problems with transmission. Only one serious problem with engine---wife drove it in 105 degree temps after radiator side tank split---until engine locked up. Towed it home, took 2 week sailing trip, came home and found rebuilt head on Ebay in Florida. Bought it for $80. When it came, told daughter to swap 'em out. Afterwards, car ran better than it ever had since we bought it. So I really want to get the tranny back into it for the long haul. How difficult is it?