Sounds to me like your 1st gear syncro is out, or the shift fork is messed up. My first guess would be the syncro, my truck is very high mileage and hard to shift into 1st after sitting in neutral.

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1989 Ranger Extended Cab, 2.9L, 8.8/3.73 LS, 4X4
1997 Expedition, EB, 5.4L, Air Ride, 4X4
2005 Explorer, Limited, 4.6L, 4X4