2001 Ranger- Transmission, 4 X 4, other

[jpuck]

Hi all, have been reading your posts in hopes of finding some answers, but so far I'm just more confused! So if anyone has any advice or suggestions I sure would appreciate hearing it. I bought a 2001 Ranger used, it seems the previous owner probably did a lot of mud bogging in it as the front frame was full of mud. I had the transmission rebuilt because 2nd and 5th gears were out. Since I got it bck it just doesn't seem right. It doesn't have the power on take off that it did, the gears engage rougher than they did, sometimes it shifts smooth, sometimes you don't feel it at all and sometimes it starts to shift then there is some kind of pulling and it finishes shifting. I sent it back to the shop and they say nothing is wrong, Ford house says nothing is wrong. A couple weeks ago I was on the highway accelerating speed and was at about 40-45 mph, it went through 3 gears simultaneously and then let out a loud noise, I thought I tore the transmission out of it but it kept on going without any problems. And then also one time when pulling out onto a road the front wheels let out a loud noise. And then I have also been noticing this small surging coming from the rear end. During this same time I noticed a small leak under the front end. One evening as I slowed down to stop at stop signs the indicator hand on the oil guage started jerking eradically, but only in the normal range, the oil pressure did not go up or down. Then I took it to a mechanic for the oil leak, he said in was the pinion seal, said the fluid in it looked thinner than it should be and said that it showed evidence of running in 4 wheel drive. So I took it to another transmission shop for a 2nd opinion, the guy did go out for a long drive with me. He said at first he thought I was nuts because he didn't detect any problems, but then it flared up, he said there was a problem around 40-45 mph and said he was so concerned with the rougher shifting but rather with the shifting that he couldn't feel. He also stated that the harder he drove the vehicle the better the transmission drove. Then in a parking lot he checked out the 4 wheel drive. He put it in 4 X 4 L, he said it should be going through the gears a whole lot faster than it was, when he went to put it back in 2 Wheel it didn't switch back over, after another try it did switch back. Then he switched it back over into 4 wheel drive again, don't know if it was L or H, but anyways he had it up to 45 mph and you couldn't tell any difference from the way 2 wheel runs. One comment did bother me though, he said he wasn't aware of being able to tell if a vehicle had been running in 4 wheel drive by looking at the pinion. So could this vehicle be slipping in and out of 4 wheel drive? Could water have somehow gotten into whatever because of the mud bogging and be causing problems? Could I possibly have some kind of sensor going out that is causing these problems? HELP PLEASE