Hello everyone!

I have an 06 XL with an M5OD behind a 4.2, 2WD, and a problem. It seems the reverse (backup) lights come on when I'm driving. A little experiment in the driveway suggests this can happen in 5th gear, as well as reverse (as intended). I've owned the truck for just under a year and discovered the problem only last week, when a friend was following me on the highway, and noticed the issue.

I've spent more than 2 hours searching the site, and the 'net, and come across only a couple of posts on the 'net with no resolution. Might there be some experience on this board?

I love the truck and can't sleep at night knowing the backup lights are on while I'm cruising down the highway at 59 mph getting 23 mpg...

Any advice would be warmly appreciated!

 

https://www.f150online.com/forums/tr...ht-switch.html

That's where the backup light switch is.

 

Well, I found the light switch and I replaced it. Thought maybe that would do it? Of course it made no difference.

A bit more experimentation and it seems that the reverse lights will go on in 5th gear but only if the shifter is pushed all the way towards the dash. If I wiggle it side-by-side the lights stay on. If I pull it back a bit, but not all the way into neutral, the lights go out. I haven't tested this driving yet.

So something must be worn inside the transmission.

Does anyone have a source for diagrams/illustrations for this transmission? My Haynes manual simply says "consult a qualified professional".

 

I would say consult a qualified professional, but that's not how I do things...

There are a ton of resources on disassembly and diagrams. This tranny has been around forever.