98 ranger gem codes

[Collank]

No engine light. Gem codes. I purchased this 98 ranger 5 months ago and it's had problems for near 3 months. I've had it looked to be told the iac was bad so they replaced it to no avail. Missed shifts, delayed shifts, has a real hard time going into first on downshift and never does once I've drove for near 20 minutes and sometimes does it when cold it doesn't like overdrive so 50 on the highway is all she has. When it isn't down shifting the brakes become very weak and won't slow down till it downshifts if it does. Speedometer freaks out and loses calibration, wipers cut on and off, door ajar light and dome light stay on to long, 4x4 low issues. Vacuum hubs were taken off and replaced with mile marker manual locking hubs, Hella lights wired, every fluid was changed at 155k including trans and tcase it has 166k now. I've replaced rear abs speed sensor, crank shaft position sensor, cleaned maf, cleaned throttle plate, cleaned various electrical connectors, including tcase relay module. Replaced Iac pigtail connector. I pulled the gem and it has 2009 stamped on it so it's been replaced once before. It looked clean and corrosion free as did all the connectors and wires behind the radio. Is the gem bad? One shop said Iac the other said transmission and one told me torque converter. Any help would be appreciated. After three shops I'm getting impatient. They all disregard the codes it has and blame it on the 33's