Marty Schafer

I bought a 2000 grand cherokee limited 4.7 had bad ring and pinoin 3.73 gears in front and rear I went and put 3.55 gears in the front and rear for better highway milage ... as soon as I was done the speedometer did not work and did not gain any milage son drove it until I needed an inspection it was throwing tss code so o bought 2 for in and out speed sensor. Put them in and mph still did not work and now my transmition is shifting super hard from first to 2 and then won't go in to overdrive or 3 if someone can help pls let me know

Willys55

I believe the speed sensor on the rear axle is where the odometer gets it's signal from

SteveMongr

What is the numerical error code that was displayed and was that the only one?
http://wjjeeps.com/speed_sensors.htm

Marty Schafer

. I'm not to sure the guy at auto zone used his code reader and got the parts for me but I did 2 sensor in and out my jeep ran fine until I put new sensors in then I got the hard shift and lost over dive and mph don't work with the new sensors

SteveMongr

AutoZone generic sensors? Aftermarket sensors are known to have issues in Jeeps.
To retrieve codes turn ignition on/off four times (not to engage starter, just to ignition on). On the fourth turn leave ignition on, mileage will be replaced by codes. Write them down and report back please. Following link is more detailed regarding code retrieval. http://www.wjjeeps.com/faultcodes.htm

Marty Schafer

p0500 , p0051 ,p0700

SteveMongr

P0051 = "short detected in O2 sensor circuit, Bank 2"
Trace wires from O2 sensors on exhaust near catalytic converter. Look for melted or broken insulation. Wires often pass very close to exhaust manifolds.

P0500 = "no speed sensors detected"
Either the connection or wires have an issue. Or the speed sensors are not recognized.

P0700 = Generic Transmission trouble code. "This code indicates that the EATX (Transmission controller) has an active fault and has illuminated the MIL via a BUS message. The specific fault must be acquired from the EATX via a DRBIII tool. (Input or Output Speed Sensor failures often cause this code and are a common failure part on WJ Grand Cherokees)."

I suspect the speed sensors themselves. Was there a brand name?

dave1123

There are actually 3 sensors that the PCM uses to calculate speed and shift points. The trans input shaft speed, the trans output shaft speed and the rear wheel ABS sensors. This data is filtered thru the TCM which may need to be reprogrammed. Nothing is simple anymore.