I've checked the old posts and so far the only thing i have left to check us behind the 175 amp fuse for a loose bolt.. but here goes.

2000 F250 5.4 with 255k miles. Truck shifted perfectly until this week, the trans range sensor code goes on at the same time it starts hard shifting first and second. I replace the sensor and also have it serviced, drained and filter.. still the same code.

If i put it drive from a stop it hard shifts in, but if iI put it in second gear manually then its smooth, so is it a safe guess to say its because the sensor can't guess the right gear and hard shifts in drive? It DOES hard shift from park straight into first/low gear though.

Today i checked again and got that code twice, along with a hot transmission code, which may have been from putting it into second from a stop as to avoid the hard shift?

One other side effect since that code is that when i put it back in park or neutral, the rpms shoot up and stay at 2k idle. If i turn it off and on it stays at normal idle. This would lead me to believe it's not a vacuum issue but electrical one, all related to this range sensor issue?

Not knowing much about these trucks that would take me back to the first thing i wrote, that one guy kept having the code and ended up being a loose bolt that held a connector in.

When the guys did the trans service there were some shavings on the magnet but my buddy told me that's normal for this mileage so I'm torn between this being sudden degredation or just some random electrical problem and the shavings shouldn't be cause to sell immediately.

One shop told me it could be the fact my overdrive button on she shifter is ripped off and messing up the range sensor, but its been like that for years. The dealership told me 140 bucks to diagnose and could likely be a diode sensor or something within the transmission. And also the vacuum line shop wanting to charge to check for the high rpms which I'm dismissing since it's not there on startup?

Is there a way to check the clip that goes to the range sensor using a volt meter? The guys at the shop that replaced it told me they'd guess it's fine otherwise the truck wouldn't start but maybe they're just feeding off me.

Thanks for a the help guys!