Ok so hear is the low down..

Buddy of mine drives a 98 audi a4 2.8L 30 valve engine quattra.

He was on the highway when this happened, Be said the car made a loud sound like he hit a deer or blew a tire(no signs of either) and the car stalled right when it happened. He coasted to side of road where the car would no longer move in any gears but engine starts normal with out any issues and runs fine (checked myself engine has misfire code come up But does not effect engine run time)
When i got there the car moved fine in reverse and drive, rolled freely in neutral and made no noise during moving. I Jacked the car up put it on 4 jack stands and put it into drive. I heard a rolling noise like something metal rolling around and it kept catching and making the passenger side wheel almost stop but kept moving till the car settled and just made the rolling noise and kept its idle speed. (I used my foot to stop both wheels one after the other and the noise persisted after both wheels had fully stopped and the trany was still moving.

I am a little worried that maybe a bolt or something broke loose inside the transmission or perhaps a bearing fell apart. Some of the things i think it might be are as follows.

1. Main drive shaft spinner bearing.
2. Passenger side dif bearings.
3. Object fell into fly wheel area and is stuck.
4. Bolt broke off inside trany and is floating around catching.
5. Inner cv joint on passenger side of car.
6. Trany is nuked

Any help would be great my friend has little to no cash, Also the brake light switch fault showed up and i am getting him to replace it. (cleared the fault and problem persisted and did not show again.) (he lost half his brake fluid showed signs of it having sprayed out from under the hood and over the fender while hood was closed.)