The body damage sounds kinda big I would expect at least $1000 if not more if doors and quarter panels are involved due to welding and cutting of the quarter panelsand new doors, plus paint. Sounds like your tranny is dying, not a leak, although it appears to be one. Mine did this too before it died, a leak would occur whenever the car ran not just occasionally. Tranny rebuild cost $1500 plus. As for the suspension like the other guy said, probably just a sway bar endlink or maybe a loose strut. If the car has more then 100k miles and this many problems, cut your losses. I am just saying the car may not be worth fixing.

ATX MTX swap, rear drum disc swap, drilled rotors, ported intake, optim throttle body, CAI, 7.5L MAF, adj. fuel regulator, longtube headers, underdrive pulley, no EGR, low inpedence bigger injectors, 2002 Focus Swap