92 camry problem

[Mjakaz95LE]

So tonightmy g/f and my friend decide for first time in 2 yrs to go to the argosy casino from indianapolis. We take the 92 camry w/169k and never ANY PROBS!!!! So after 75miles of driving with cc set at 75 the car does a stall like as if i let of the gas real quick... about a min later i start hearing a high pitch squealing noise gettin louder and louder so i tap brakes and it begins to go away, immediately following this i throw in neutral and begin to pull over and hit brakes.. at that time we start hearing some grinding and what sounded like metal clunking around. So now stopped we sit there on side of I74E in shock of wth just happened! so i pop hood and check tranny fluid (looks clean, level and no metal) no leaks underneath but smelled like something was burning. well car is in park and i lean on it as im lookin around bent over with flashlight and car starts to roll backwards non stop in PARK!!!

So we put in neutral and push it back about a half mile to the rest area we had just passed. As it rolls in neutral backwards it is making grinding noises.

So here goes my mechanical skills educated guess..... im going to say its the differential, i did attempt to put in drive again but it barely moves and grinds and clunks as it tries to move.

Another reason to think differential besides the obvious facts of..... 1- it rolls freely in parkwith lovely noise... 2- in neutral it grinds/clunks and only parts moving in tranny is differential...3- For 6mons + when u turn to right only it would make a clunk sound with a sort of shudder feeling at your feet

So assuming that is what it is and the fact i now have to borrow friends truck and a dolly 75 miles to pick it up and to tow it home 75miles and pop out pass axle and diff cover to inspect diff where in the hell do i get a diff and how much would it cost?

Has anyone else dealt with an issue such as this? I guess ive never heard of a camry diff going bad on a 100% stock babied car! not saying it cant or wont happen or shouldnt for that matter just that it seems odd. Ive had several friends w/gtp grand prixs that have destroyed many diffs due to adding so power.

Any suggestions, help and/or how to's on the procedure and what all is needed to R&R the diff would be appreciated, i need this fixed ASAP!!!

thanks all!