1998 Ford Explorer 4WD, caliper bolts, & transmission

Yes, that is the correct mileage; no, I haven't had anything MAJOR replaced on the car; yes, I realize I am extremely lucky and this auto has far exceeded any expectations I ever had (Right on Ford!); And yes, I am knocking on wood constantly and thankful it still runs because buying a new car is not an option at this time. That being said. I was told by my mechanic two years ago that I needed to have the control arms replaced as part of routine maintenance. Instead of letting my mechanic do the work; I opted to take it to the local Sears Auto Center because I had a Sears Charge Card and that would allow me to defer the cost until later. When I picked up the car from Sears after the work was done; I noticed it was making a funny clunking noise (the trip home from Sears was less than 4 miles and did involve a short interstate ride). I noticed as I made left turns in-route home that the noise became more prevalent and even could be described as grinding. I turned left into my driveway at home and the car began to violently shutter & grind (almost as though the 4wd had kicked into "high" by itself). I was going to back out of the drive and return to Sears but could not get the car to go into reverse. I decided my only option was to turn sharp to the left and drive thru the front yard (basically making a u-turn) to return to my street. As I turned left, the grinding and shuttering continued until there was a loud thud and then the left front wheel fell off the car flattening the tire, warping the rim and sending the exposed axle into the ground of my front yard. I immediately called the assistant manager at Sears and he drove over and called a tow truck to take the car back to Sears. They told me that the caliper bolts were not replaced (or tightened) correctly. They kept the car a few days and said they had fixed it (they did pay for a rental car during this time). When I picked the car up the 2nd time; on the way home as soon as I got on the interstate and got above 60mph the car began to violently shudder. I immediately returned to Sears and made the manager ride with my. The shuddering continued on our ride and was so violent that it actually scared us both. We returned to Sears. They kept the car for a few more days (again paying for a rental car for this time) and then called to say it was ready again. After picking up the car for a third time all seemed fine but it wasn't too long (a couple of days) that I began to notice a loud skipping "cluck" when pressing the accelerator while increasing speed or climbing small hills. This skipping cluck became more and more frequent to the point that it was almost constant whenever there was an increase in power necessary to accelerate. It was almost like some one was under the car beating it with a baseball bat. I once again returned the car to Sears where they kept it a couple of days and returned it to me saying they could not find anything wrong with it. I once again had the service manager ride with me to demonstrate the problem and he said that the problem had nothing to do with what had happened to the car (with the whole wheel falling off and grinding and what not). I continued to drive the car and the problem became so increasingly bad that I finally took it to a transmission specialist. He kept the car for almost 3 months and $900 later, thought he was finally able to fix it by replacing everything that went through the transfer case & cleaning it out real good. After I picked up the car it wasn't too long before it once again began to do the skipping cluck & got to be as bad as before so I took it back to him (the transmission specialist). He kept it a few more weeks and returned it after working on it for no additional charge. That was over a year ago and I haven't had any problems with it since (this is where the knocking constantly on wood comes in). My long winded question is this. Could the front wheel falling off of the car forced the 4wd to engage in a way that would have damaged the transmission to a point of causing those problems? I never had any issues with the car until that incident with the wheel falling off & no one seems to be able to explain or understand how those could all be tied in together. The car has been operating great for almost a year. I recently had a flat tire and upon changing it to use the spare (the ORIGINAL spare) realized that the spare was actually one of the Firestone recalls. I had had the tires replaced back when they were recalled but for some reason; they forgot to replace the spare. I took the spare to a Firestone store and they replaced it with a similar tire under the recall. The original tires (& this new replacement) were actually larger than the tires I had been buying for the car. They put the new larger tire on the front of the car and I bought a new larger tire from them to match it & placed the smaller used tire I had been using opposite the flat under the car to be my spare. I asked the Firestone tech if that was acceptable to have different size tires on the (4wd) auto and they said it would be fine. On the way home the same issues began all over again - skipping clunking and almost dragging like the 4wd was trying to engage. I stopped by the ford dealership on the way home and the service tech I spoke with said that was absurd & that in NO WAY should an Explorer with auto 4wd EVER have different size tires on it & that the car would interpret that as needing to engage the 4wd b/c of the difference in rotations. I returned to Firestone and had them replace the tires with all the same size, but not without their resistance & insistence that it should not matter. This leads me back to my question and assumption that the wheel falling off the front of the car when the caliper bolt was not replaced correctly would / could cause the 4wd to interpret that same scenario because that tire was not rotating correctly. Again, could this have caused the significant damage to the transmission and how? Like I said before, no one has understood or been able to explain a connection to this. Thank you in advance for your assistance.