2000 GC error code p0720

[messingabout]

I have a 2000 Grand Cherokee, 4.0 with 125,000 miles. Today, while on the highway, but in traffic, the tranny began to slip. It felt as though the the brakes were sticking at low speed, then at +/- 60mph, the tach was at 3000 rpm. Typical tach at 60 is <2250. Almost felt like overdrive was stuck on, but it was not engaged. The car stalled at an off-ramp, but started right back up (in Neutral) seemed to run fine after that. However, upon checking the tranny fluids (in neutral) the fluid was a little foamy. I let the car sit for a while (30 minutes). Checked error codes and got P0720, low output Speed Sensor RPM above 15 mph. Am I looking at a new transmission? or is this something less drastic. Overall the car runs fine and there did not seem to be any loss in performance after restarting, but the check engine light is on and I do not want to kill the tranny. Any Help or info is appreciated. (sorry for the length of the post)
MSR

[eric umbright]

Originally Posted by messingabout

I have a 2000 Grand Cherokee, 4.0 with 125,000 miles. Today, while on the highway, but in traffic, the tranny began to slip. It felt as though the the brakes were sticking at low speed, then at +/- 60mph, the tach was at 3000 rpm. Typical tach at 60 is <2250. Almost felt like overdrive was stuck on, but it was not engaged. The car stalled at an off-ramp, but started right back up (in Neutral) seemed to run fine after that. However, upon checking the tranny fluids (in neutral) the fluid was a little foamy. I let the car sit for a while (30 minutes). Checked error codes and got P0720, low output Speed Sensor RPM above 15 mph. Am I looking at a new transmission? or is this something less drastic. Overall the car runs fine and there did not seem to be any loss in performance after restarting, but the check engine light is on and I do not want to kill the tranny. Any Help or info is appreciated. (sorry for the length of the post)
MSR

I have a '99 that just gave me the same code over the weekend while sitting in traffic from the brickyard. According to www.wjjeeps.com/speed_sensors.htmthe speed sensors are relatively easy looking to replace, and there is even a diagram included. I have not attempted yet, but they list the sensors cost (input and output, depending on either the 42RE tranny or the 45RFE/545RFE tranny
should run less than $40.00 each.