I have a 2001 Navigator 4X4 with 180,000 miles. I ran it through a watery mud pit yesterday, just to see if it would make it and it went through fine. I noticed later however, after it sitting for 3-4 hours and then driving home, it wouldn't shift into 3rd/4th and so I carefully limped it home. The transmission got a little hot and started puking some fluid by the bell housing inspection cover, the fluid was clean and red, and didn't smell burnt. I checked the stick and it was dry. I let it sit over night to cool off and to dry out and made a short run just to check and get some fluids, still no 3rd/4th, but it didn't leak. Unfortunately, I didn't check the trans fluid level before I ran it through the pit, so I don't know if it was low or not. The only code it's throwing is a P0708, range sensor, which I have a new one and haven't changed it out yet. I can't get to the control solenoid plug to clean any water or mud out, no room.

My question is, do I just go ahead and drop the pan and the valve body, and replace the 2-3 shift valve right away, or is there something else I should look for first?
~Thanks!

 

You should know that you should NEVER take an auto trans vehicle into deep water or mud as the friction clutches are bonded onto the steels with a water soluble glue. That said, I suggest that you drop the pan and change the fluid and filter while looking for any trace amounts of water. If you find any water you may need a rebuild. The common cause of a fluid leak at the bell housing is the front seal failing, for whatever reason. That needs to be addressed, hopefully before the front pump or torque converter fails. I think you need to consult a transmission shop before it's too late for a minimal cost repair.
If the trans is damaged due to water the comprehensive portion of your insurance policy may cover the repair cost.

 

That's your very first step since that's the code you're getting. If the case of the sensor was cracked and water got in, then your whole shifting pattern is toast. Change the range sensor and see if it shifts normal again.

 

Huh? It's a 4WD vehicle, it's meant to do this.

 

It all depends on the depth of the water. If water reached or a lot of water splashed over the trans vent you will likely ingest water. The same goes for the differential(s) as the traction-lock clutches are the same as the trans. Water there is also a bad thing. All serious mud trucks have the trans and differentials equipped with extended vent systems for that reason.

 

I think I found the issue. I went to unplug the TRS, and I noticed that the connector for the Transmission Range Sensor is shot. Pin 5/wire TR2 and pin 3/wire TR3A are totally corroded and broke, and pin 5/wire TR2 had one strand of copper wire left. Judging by the build up of oxidation "verdigris" on it and the brittleness of the wire insulation, it didn't happen from running it through the pit (although it probably helped to finish it off). Have to order a new plug and wire it up, and then go from there. The fluid was only about a quart low and it's not leaking now.
Thanks for the input and help.

 

Good or you. I suggest that you go ahead and change the fluid and filter, looking for any sign of water while you're in there. The front seal could still be a problem.

 

you sure dodged a bullet this time.

 

As I was replacing the TRS plug, I also pulled the pan and valve bodies and found the problem. The 2-3 shift valve was stuck. The Navi is working fine now.
Thanks again, to all who commented.