I have a 2001 ford expedition just put a "new" engine in it but when put in gear it dont want to move or rev up. it does rev in park or neutral

now it will not start move lever back and forth in park or neutral no good ????? When you turn the key to the start position ,what happens ? Nothing ? I'am assuming this because of your statement about moving the gear selector from park to neutral . The first thing to do would be to look at wiring diagrams to see what all is involved in the starter electrical circuits . Then understanding how the electrical circuits work an then using a DVOM - digital volt ohmmeter to test the electrical circuits .

Free wiring diagrams here http://www.bbbind.com/free-tsb Enter vehicle info. Year , make , model an engine . Under system click on engine , then under subsystem click on starting . Click the search button then the blue link . Looking at the diagram I see the fuse that sends battery voltage to an through the park neutral switch to the starter relay . You can test for B+ voltage at pin 85 , if when in park you see B+ voltage there ,nothing is wrong with the park neutral switch. Pin 30 should also have battery voltage . Using a piece of 12 Gage wire , jump pin 30 & 87 , that is , where the relay plugs into in the fuse / relay box. If the starter an cables are good ,the starter will crank the engine over .

U have serious tranny problems. Sorry.

If it works fine when warm replace transmission filter and fluid. the filter is probably blocked and when cold gets no fluid through it. if this was helpful please leave good feed back

something to do with the nuetral safety switch and gear linkage--getta haynes manual for ajustment details

Assuming your vehicle has an automatic transmission, and if it just started doing this,your probably low on transmission fluid. if this has been going on for some time....there's a good chance the transmission has been damaged permanently. That is to say....if you have repeatedly put the car in gear and revved the engine and or driven it while it is slipping badly, it doesn't take too much of this to burn up your transmission. If the former is your case, with a warm engine in park, emergency brakes set, level ground...check your transmission fluid level on the dipstick ( it should be labeled) the checking xxxx mark at the top represents full when the fluid level is covering it. Unlike the engine oil, the xxxx represents 1 pint, not 1quart.

Theroadisalover

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replace the neutral safety switch or also try rocking the vehicle forward and back and then trying the shifter again.if it is parked tight against a curb and had rolled forward just a little bit and came to rest with the vehicles weight against one tire this will cause a bind and won't let it out of park this is especially true of 4x4 vehicles as the mileages get hire I hope this helps and good luck

brake-sahift interlock solenoid not working. check fuse first. when key is on and brake is pressed, it either activates or deactivates the solenoid so you can shift out of park. safety thing.
chrck owner manual for a mechanical overide process. maybe there is one.

Try to get free mechanic help I tried this it rly works

So your problem is that the shifter indicator is not correctly aligned? If so look under the dash at the bottom side of the steering wheel, set parking brake, move the gear selector handle and look for the moving part under the dash, this is the indicator cable, it has an adjustment on the mount usually a thumbwheel, the indicator is spring loaded to stay in the park position, use the thumbwheel and adjust the indicator back to P while handle is in park position, then test to see if it is working properly, if you are unable to adjust to proper position the spring unit may be damaged, and it is replaceable by removing the dash, then removing the indicator unit, I would just get one from a wrecking yard from a wrecked Expedition and adjust to your vehicle. Hope this helps, let me know.

Input or output speed sensor,Incorrect fluid or fluid level,neutral safety switch,or TCM (transmission control module)