Truck shifts into reverse during hard brake

[airplane mech 22]

I have a 2006 4.0 v6 and the transmission will shift into nuetral or reverse during a hard brake. there is no indication of this until the light turns green and I start to go backwards when stepping on the gas. I changed the transmission fluid but the problem still exists, but not as often. anybody have a clue what the deal is?

 

[Town]

So the trans gear selector (inside the 5r55 trans) is moving one or two gear positions (one or two detents anticlockwise) while the gear shifter is still in the drive position? Have you checked the gear shift cable at the driver's side of trans. Something appears to be loose or worn or misrouted. The cable would need to be moved toward the front of the vehicle and pulling the gear selector lever in the trans with it to achieve this.

On the V6 the gear shift cable attaches to the trans at the Digital Transmission Range selector (TRS) sensor. Two adjustments are required (gear shift arm to cable and the TRS to align with gear selector position). There may be a problem with the way the cable has been routed or adjusted so that there is pressure on the cable (perhapse up or down) to move the gear selector shaft under braking while not moving the gear shift lever in the center console.

Never heard of this problem before.

I have the adjustment procedures if you want to PM me your e-mail address.

Good luck.

 

[Town]

I may have been mistaken in the travel direction to go from D to N.

I think the selector lever at the trans will move clockwise from the D position (just about upright) to the N position and another detent to the R position, so the next (last) detent position going clockwise will be P. So the inner and likely outer shifter cable would be pushed toward the rear of the vehicle to move from D to N to R.

So perhaps the outer cable is not properly fixed to the trans allowing the inner and outer cable to move backward and push the gear selector lever backward one or two detents without changing the position of the shift lever in the center console.

Just guessing of course, because nothing actually makes logical sense.