2003 Chevy Silverado 2500 duramax won't shift into park. It will go from reverse all through the gears into 1st I checked the linkage under the dash everything is connected.

Elizabeth, Shifter mechanism or linkage probably faulty, have a good technician have a look, diagnose and estimate repair. Check the attached links,instruction and guides, Good luck
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Won shift back to Reverse or Park Stuck in 1st gear MBWorld org Forums

Sounds like the reverse band or servo has gone out. Transmission shop needed for a confirmation.

your shifting pattern seams off , as follows P R N D D1 D2,
Will it go into any gears closer to park ? did you try turning steering wheel , next I would look under at tranny linkage to see if there is something stopping it. that will require 2 people 1 in truck and 1 underneath.

Do you feel some play between the linkage parts?
If it's too much play, then that's the problem

you need to check the code that it set with a scanner and it will lead you to where to check to fix problem

Have the ecm scanned for codes. It might have a bad speed sensor or range switch.

Make sure you car is actually in PARK, Easy to do, Just disengage the parking brake (emergency brake) and attempt to push your car both forward and reverse to ensure your car isnt in neutral. If you cant budge the vehicle your good to go! If it rolls forward it may be in neutral or a forward gear. if it rolls backwards it may be in neutral or reverse. If it rolls both directions its in neutral. On that note if it moves at all skip to the third step (***) and make sure the transmissions shift bracket is in the park possition. Depending on your cars transmission model the parking gear is located all the way left to the farthest possition or all the way right to the farthest possition) One direction will put you in Park, the other in will put you in 1st gear, If your in 1st gear the linkage should be too far away from the shift plate to connect if your column says you are in park. DO NOT ATTEMPT TO START YOUR CAR WHILE IT IS IN A DRIVE GEAR AND THE LINKAGE IS DISCONNECTED IF YOU ARE ABLE TO START YOUR CAR IN ITS CURRENT STATE DO NOT MOVE THE TRANSMISSIONS SHIFT BRACKET UNTIL LATER IN THIS INSTRUCTIONAL!!!!!

* Floor shift automatic, the push pin lever (located inside your shifter/gear stick) may be malfunctioning. You have to pop the grip off and inspect the white plastic pin inside the shaft to see if it is damaged, also check inside the grip while you press the safety release (shift lock button) to ensure the internal slide mechanics are propperly working). Also check for anything obstructing the levers movement inside the floor housing.

** Column Shift. Make sure your pull pin lock is working properly (disengages the shift lock when you pull back the gear shift before you select a gear) if its broke theres two possible behaviors you'll experiance -1. You cant pull the gear shift back at all or -2. No effort or less than normal effot is required to pull back the gear shift. If all that checks out then you have to inspect the steering column linkage bar (you may have to remove some of the steering column housing to view it. Make sure the bar isn't bent or that its movement isnt obstructed.

***Automatic Transmission Linkage Check - Look under the kick panel located above the gas and brake pedals.........Once linkage is located under the dash (kick panel) disconnect it and try the gear shift. If the cable moves under the dash then reconnect it and move on to the next step.
Now block the wheels and climb under the car and disconnect the linkage from the transmission and have someone work the gear shift while you see if the cable is operating propperly, if the linkage moves (as it should) then try shifting the transmission back and fourth by hand while the linkage is disconnected., If the shift bracket feels stiff or is dirty clean it off with non corosive chemicals so you dont damage any seals. If the bracket operates smoother go ahead and reconnect the linkage and try shifting with the column again. Be sure to move the shift bracket back to the park position and make sure your shifter column is in park as well before you reconnect the linkage, if you dont you are sure to run into more issues.

Hope this helps you out! If all the mentioned area's above are in working order then your problem is with the car's transmission and you should take it to a speciallist.

Your problem probably lies in the linkage, there are nylon bushings in the linkages to the tranny that get brittle and break over time.

Check your linkages, and you will probably find what I have reffered to.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/sean_54c3a3dc48a7773c

yes it could. if they share a ground and its got some issues alot of times thins in the same place(like in a dash) share ground's if yours is loose this could easily cause that problem. have you checked your fuses yet?

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