HOW TO: Change T-case Position Sensor - Quick Method Under Vehicle

[redpoint5]

The "part-time" light was flickering on my '02 Liberty, especially when I was decelerating. I was concerned that it was engaging 4-wheel drive, but it turns out it wasn't. The sensor merely indicates the mode that the transfer case is in (when it's working properly).

The part was $64 shipped from MoparOnlineParts.com

It was very easy to change out from underneath the vehicle. The Jeep was already on stands because I was already changing brake rotors/pads. It took 1min to remove the sensor once I figured out where it was. Putting the new one back in took 10min because it was difficult to line the threads up just right without being able to see it. It was difficult to thread the sensor in when the button was depressed and resisting my effort to install. So, I found that placing the T-case in 4Lo made installation easier since it depressed the switch the least.

A vice grip was all I used.

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Location of sensor.

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Reuse the O-ring.

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The old sensor was flaky and often went open (no resistance) throughout the range of motion. Here are the resistance values it had:

2WD-------------------------1183 (very inconsistent)
4WD PART TIME --------------684
NEUTRAL(Full Time,242)--------410
NEUTRAL----------------------220
4WD LOW ---------------------open (malfunctioning)

The new sensor had the following resistance values with no fluctuation:

2WD-------------------------1182
4WD PART TIME --------------684
NEUTRAL(Full Time,242)--------410
NEUTRAL----------------------210
4WD LOW ---------------------60

The post by tjkj was extremely useful for troubleshooting my old sensor, so I'm hyping it below.

OPERATING MODE----SENSOR RESISTANCE (ohms)

2WD-------------------------1124-1243
4WD PART TIME --------------650-719
NEUTRAL(Full Time,242)--------389-431
NEUTRAL----------------------199-221
4WD LOW ---------------------57-64

 

[Elmer]

You're absolutely right, it is extremely easy to change out from underneath the vehicle. I didn't even need to jack it up. No need to tear out your center console.

I used a 3/8" drive ratchet with a 1/2" drive conversion and normal (not deep socket) 1-1/2" socket. As I've seen others mention, the hardest part was unclipping the connector. There is a release on one side that must be pushed in order to remove the connector. This can be tricky since you're doing it blind.

I found that placing the T-case in 4Lo made installation easier since it depressed the switch the least.

This is key. I attempted to thread on the replacement sensor while in 2hi, but it was damn near impossible to line up the threads. Kicked it into 4lo and it was on in a couple seconds.

 

[dude1116]

So does this come out by hand? What is the method to get the sensor out? I might do mine soon.

 

[Elmer]

So does this come out by hand? What is the method to get the sensor out? I might do mine soon.

I used a 3/8" drive ratchet with a 1/2" drive conversion and normal (not deep socket) 1-1/2" socket. As I've seen others mention, the hardest part was unclipping the connector. There is a release on one side that must be pushed in order to remove the connector. This can be tricky since you're doing it blind.

 

[dude1116]

Yeah I don't know if I was just not reading or sleeping when I wrote that.

Any issues driving without the sensor? I might just pull mine for later replacement.

 

[Snail Farmer]

It would probably be ok to disconnect it, but I wouldn't recommend pulling it out completely until you're ready to replace it.

 

[tjkj2002]

Any issues driving without the sensor? I might just pull mine for later replacement.

Leave the sensor in place unless you want to replace the t-case also.


Changing my t-case sensor is super easy as it's zip-tied to the side of my trans,no port in a Atlas for it.Maybe someday I'll splurg and get the fix from Advance Adapters to make my dash light up when in 4hi and 4low,nor really worth it at the moment for $220.

 

[dude1116]

Leave the sensor in place unless you want to replace the t-case also.


Changing my t-case sensor is super easy as it's zip-tied to the side of my trans,no port in a Atlas for it.Maybe someday I'll splurg and get the fix from Advance Adapters to make my dash light up when in 4hi and 4low,nor really worth it at the moment for $220.

Yeah same. Someone on here tried to make the argument that the position sensor affected engine coasting. But I doubt that's true. I'll probably leave it in place.

What got me to think of this again in the first place was that mine, for some damn reason, started lighting up again. After 2 years of NOT lighting up AT ALL.

 

[tjkj2002]

Yeah same. Someone on here tried to make the argument that the position sensor affected engine coasting. But I doubt that's true. I'll probably leave it in place.

What got me to think of this again in the first place was that mine, for some damn reason, started lighting up again. After 2 years of NOT lighting up AT ALL.

Actually for '02 KJ models that sensor does effect ignition timing when in 4low to add a little more HP and torque at low rpm's.Not sure about any other model years that do that but I know '02's it does.

 

[dude1116]

Actually for '02 KJ models that sensor does effect ignition timing when in 4low to add a little more HP and torque at low rpm's.Not sure about any other model years that do that but I know '02's it does.

Interesting. Might be worth the fix then. Most likely not. Thanks for the info! Much obliged.

 

[FortKnight]

Just did this job on my 2006 CRD. While I admit as others have said, 10 mins from underneath might be optimistic, it really shouldn't take you more than 20 mins.

My tips:

1) Put your TC gear selector in 4lo

2) Lay under your jeep on the drivers side, around where the front/rear door meet - With your feet towards the back of the jeep (So you're facing the back).

3) Look/reach up on top of the transfer case, you will see the sensor right on top. If you cant see it, look for basically the only wire harness leading to that area, it will be to the sensor.

4) Don't fight with trying to get the plug disconnected. Just jam a pair of knipex/vice grip pliers up there and give it a quarter turn. You should be able to loosen it by hand after that. Once its out, just pull it down with the wire still connected. There is plenty of length, and then you will be able to easily see how to disconnect it.

5) Swap the o-ring to the new sensor, and re-connect the wire.

6) Reach up, find the hole, put the sensor in it, and turn it THE WRONG WAY about 5-6 turns. This will accomplish 2 things.
a)It will help you line the hold/threads up.
b)It will back twist the wire, so when you ***** it in, the wire isnt spun up. (Basically you are unspinning the wire, so once you spin it in, its back to neutral-ish position.

7)Jam your pliers in there to snug it up.

Congrats, your TCasedash light is correct again. Don't forget to put your TC back in 2wd before driving away.