Steering Wheel Vibrate problems of the 2004 Nissan Xterra

First -my steering was getting hard - I asked a tech at Nissan what possibly could be the problem. They suggested change the steering fluid first. I did and then I learned there was a recall - I would like a reimbursement of $96. 25 for the steering power fluid flush that I did not need. I was never notified and found out by calling Nissan because the problem was still happening. I took the SUV into Nissan service to do the recall repair - it was done however, I still had a hard steering problem. They looked at it again and they now said I needed a gear box which I recorded earilier with you in a previous complaint . If I do in fact need a gear box I feel that it got defective due to the recall - this is over a $2,000 repair. A very short time after my car left the service department (after they said I may need a gear box) I almost had a very bad car accident - my front tires and steering wheel began to shake and the wheel felt like it was coming off - I towed the SUV to Nissan service and I am now told that the tie rod assembly needs to be replaced at a cost of over $700. 00. Why did they not see the problem the week before? I want to be reimbursed for $96. 25 steering power flush, towing charge of $120. 00 and the tie rod assembly replacement approx. $800. 00 and I want this investigated. Do I really need a gear box? I could have gotten into a very bad accident if that wheel to fly off. Please look into this problem. Thank you - Nissan Xterra 2004 your department and Nissan needs to look into this problem - I could have died. Does it have anything to do with the 4 wheel drive?.