Will not shift?

From full stop acts one of two ways it'll either start slipping until I let up on the throttle or the clutch pack engages late and grabs hard. It's also acting up when maintain higher speeds. Especially around the 40 to 50 mph. It feels like it is jumping back and forth from what I'm assuming is third and fourth gears. People told me to replace the park neutral safety switch. It did seem to subside the issues for a couple drives but it came back. It may have been coincidence or it may be that I don't think the transmission fluid I don't think got to temperature. Could this be a solenoid? If anyone can help I'd greatly appreciate it.

Hello, I have a 2000 F-150 4x4 108,000 miles auto trans. I was headed to work yesterday and when I got on the highway I pushed the OD button. As I was going I noticed it didnt shift into OD I didn't think much about it until I went to pass a car it kicked into passing gear and wouldn't shift back into drive. Then when I stopped and took off again it wouldnt shift out of first. I moved the shifter to second and it shifted but wouldn't go into drive when I shifted it to D it stayed in second. When I stopped and put it in park the RPM's redlined and I shut it off. When I started it back up everything was fine on the way home it seemed as if the throttle wasn't quite as responsive as it was before. It seems to take a while to idle down and when I turn on the defrost the idle jumps up about 400 rpm then comes back down. I am thinking it is the TPS but that doesn't explain the tranny problem. I am a weekend grease monkey just need some place to start Thanks P.S no check engine light

I will go and see what they say and let you know. Thanks again

Went to Autozone and had a scan I believe the code was p1201? It came up TPS not consistent with MAF. I put a TPS on it and imediately noticed a difference. Thanks for your advice I didn't know that the computer would show a code even if the CEL does not come on. I will definately use you guys again and have recomended you to 3 people already. Have a great day. Brandon

I finally bought a vehicle I decided on a listed above. What i'm wondering is it shifts. Not really hard. I can feel it shift from 1-2 or 2-3. Feels like it pulls quick it's hard to explain. Smooth shift after that. I can feel a bump into gear. Fluid is right up there where it's supposed to be. Not burnt at all but I have no records. Looks clean. Thinking about changing the fluid. Something to worry about? I think it's the 4R70W transmission. No check light or codes. I just don't like that shift. I've been really babying it.

Thank you. I think I will get the fluid changed and keep an eye on it. Thanks for the advice sir. It's been a couple months how long before it get worse if it does? I suppose it's hard to say.

It's been awhile since I posted this, but the problem was a broken spring.

I posted last November about kind of hard shift from 1 to 2. It was an easy fix (accumulator spring). Now I have noticed a late shift a few times. I'm going 55 down the road and suddenly I feel the truck shift. Not down shift but seems to be going into gear at 55? How do these trucks shift? 4R70W