I have a 2000 XJ with a P0715 code. I was driving then all of a sudden it shifted itself into neutral while gear selector was still in D, pulled over and restarted the car and it drove off fine. 20 seconds later it did the same thing, reset it again and got it into Drive one more time before it finally would not go into any gears except for neutral and Park. I looked up the code and it says the most common cause for this code is a input or output speed sensor. I'm just unsure on where to even start on this, has anyone else experienced this problem or have any suggestions on what to do or where to start? Thanks

 

Start by checking the fluid level and see if it smells burnt.

 

Well I checked the fluid and It definitely did not smell right. I couldn't check the fluid level because I cant put it in gear to warm up the transmission. If I pull the dipstick out the fluid level is right about at where the stick starts to curve and twist, above the max line. I unplugged the TCM and tested the speed sensors via the connector prongs. The Input speed sensor read 681 ohms and I couldn't get a reading on the output speed sensor, not sure if it really wouldn't read or If I just didn't have the prongs at the right angle but it never read any ohms. I pulled them both out and the Input read the same and the output sensor read 623 ohms. I also forgot to mention that 2 days prior a shop put a new flex-plate and Torque converter on. Could either of these be the culprit or should I focus more on sensors?

 

Yes, a failed flexplat of torque converter would cause these symptoms. Pull the inspection plate on the front of the bellhousing and have a look.

Also check that the cable from the throttle body to the transmission is properly adjusted. Lookup up bleeping jeep's video.