What is the second drive gear for

You have too much fluid in the transmission. Park on level ground. After a 15 min drive. Leave engine running. Set parking brake. Transmssion in neutral. Check tranny fluid. A cup or more over will cause this. Better to have less than too much. Drain at least a full 1 leter bottle. Go for drive check it again. As above.

Depends if you have a regular 3 speed automatic, or a 3 speed with overdrive.
Put it in drive, it will start out in first gear, then shift into second at about 15 MPH, into third at about 30-35 MPH. With overdrive, fourth gear will kick in at about 45-55MPH.

yes its inside the unit

check shifter lever for adjustments

Try putting the transmission in low or 1st gear manually shift it down and try taking off as you accelerate shift it manually to 2 then drive. Did it take off like it should when you put it into low and then shift up or did you feel more power when it was in low if so it sounds like the transmission is not going into low gear but taking off in maybe second gear or even drive. When it takes off in any other gear but low it will start slow and sluggish and as you begain to gain speed it will start feel normal but thats because the speed matches the gear you in at that point.If my assistance was helpful please take the time to rate my assistance thank you.

it might be that your gear oil needs to be changed..it is supposed to be changed every 96,000kms or every 48 months...which ever comes first....

Take it in for proper diagnosis - that's not supposed to happen in an 'ALL WHEEL DRIVE' - all WHEELS ARE SUPPOSED TO TURN.

The clutch bearing is supposed to have a groove on the inside where it slides on the shaft That groove is supposed to have a heavy grease applied to it to prevent the bearing running dry on the collar it slides on.Regardless of your driving style, that grease is intended to remain there for the life of the clutch, (generally every clutch I have ever replaced still had some remaining lube there unless the bearing itself failed from a material defect which caused it to overheat and cause that grease to then run out of the retaining groove) I'm not there and can't see the old parts, but in my opinion the first clutch may have failed partially because of your lack of skill in using a stick shift vehicle but the second failure obviously is not your fault if the information you have posted is correct.
Good luck

Test the transmission module. It controls everything the transmission does, the timing of shift points, gear selection, overdrive, etc

if you are going to fast and down shift of course its a grind maybe your suppose to be on 4th gear not third gear so that means you need to shift to 3rd.