It's really no harder than an oil and filter change. Maybe easier. I would swap the sensors as long as you have them out already. I only had the reverse problem. My logic in swapping them was that if a sensor was bad the symptom should change. But cleaning fixed my problem. I will list the steps from memory.
Remove air box top cover. You need to remove a couple of electrical plugs and 1 hose connection to do this.
Remove air filter media.
Remove 3 bolts at inside bottom of air box (note 1 is longer)
Loosen clamp, left side of air box.
Air Box can now lift out (notice grounding wire under front right bolt that grounds to trans)
1 sensor is directly under air box the other faces the battery at a 45 degree angle.
Remove the sensor electrical connector.
Remove the 12mm bolt that holds in the sensor.
Twist and lift the sensor (it is only an o ring holding it at this point)
You should find some metalic fuzz on the end of the magnetic sensor. Clean this off.
Lube the o ring with a little trans fluid and replace.
Reverse above steps to put back together.
Check this link out. Lexmex posted a picture of the sensor on a removed transmission. Also read my post at this link about different versions of this sensor.http://www.clublexus...ad.php?t=354197