97 f250 HD 5.8L e40d, trans shifts bad from 1-2, and feels like it slips out. i replaced the trans range sensor but still having problems. is the 3rd brake light being out a myth or real trans problem? mine is out, replaced the harness and bulbs and still nothing, also done light in side does not work when door opens. can someone please point me in the right direction

 

Yes, brake light problems will cause weird trans problems. Make sure everything is grounded properly, use jumper grounds strait from the battery, and go from there. Good luck!

 

I have to say in my recent experience the 3rd brake light being out was NOT the issue. As I was trouble-shooting similar tranny issues replacing that was the first thing I did and it didn't help. After running the codes I replaced the vehicle speed sensor and that didn't fix it. Last ditch before taking it to a shop I purchased a new transmission range sensor (sometimes called other names but is what the dealership by me called it) as well as enough Merc 5 to do a fluid flush. After the flush and putting it all back together again I went to fix the TRS and it was not 100% plugged in! I cleaned the sensor plugged it back in and no problems since. That was about 1,500 miles ago knock on wood.

 

The 3rd brakelight is controlled by the brake switch which controls converter lock-up so in theory it could cause a problem. My comment was more brake lights in general. Make sure and check accessory plugs such as trailer light plug-ins too.

 

I did not have the interior light out as jhales91 does though.

 

I did it in reverse order, just replaced the Trs yesterday from ford and no luck. I will try the brake light. Maybe it is still effecting it

 

Missed the interior light thing the first time. That really points to a ground problem.