Went to move my MCS 2005 auto and it slammed into gear, never had an issue before. It will move forward and in reverse but slams into gear. I drove down the block and it will not shift and the check engine light came on. Drove great and parked it for a couple hours then this happened. I was changing the rear back up bulb and that's when I thought I'd start it and check reverse. Just over 70,000 miles. Not good! Any thoughts?

 

Also, when I first put the bulb in I keyed the ignition and put the car in reverse, engine not running. Went to the back and no lights so I thought I needed the engine to be running and that's when all this went wrong.

 

Update,
Searching all possibility's I thought about what if somehow I messed up something putting a little bulb in? I started looking at perhaps something got shorted out installing the back up bulb...yep! New bulb installed blew the 5 amp back-up fuse in the side panel, no clue as to why. Removed bulb and changed fuse and all issues solved. WTF! How can 1 fuse cause a trans to bang into gear like a semi just rear-ended you and not allow the trans to shift gears? Anyhow problem fixed but I still have only 1 back up light working. lol

 

Oh, the marvels of modern electronics...

Check your backup light assembly, it is possible that the side that is out has shorted and that is the culprit. I have seen this happen on some of the newer cars e.g., 2012 even after replacing the bulb it still ended up having to replace the entire Reverse Light assembly.

Are your Reverse Lights part of your taillight assembly or is it the the small light assembly above the exhaust tips?

Motor on!

 

Update, I did some more research and the squid at Autozone gave me a 912 bulb and it should have been a 921 bulb. I'm guessing the blown fuse powers a bunch of unrelated stuff like the safety neutral switch ect... confusing the computer. Hope no damage was done from the couple times I moved the car. Thinking of doing a trans flush just to be safe.