2006 jeep grand cherokee transmission speed sensor location

Q: What happens when your transmission speed sensor goes out?

When theres no speed signal coming from the sensors, shifting of gears will be a problem because the powertrain control module wont control them correctly. This will make the transmission not work properly. It will either shift more quickly or roughly than expected.

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Table of Contents Show

Sensor failure:
Speed sensor removal
Speed sensor installation
WJ speed sensors
Where is the transmission speed sensor?
What happens when your transmission speed sensor goes out?
What are the symptoms of a failing speed sensor?

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Welcome to the JeepSpecs.com in-depth page of WJ Generation Jeep Grand Cherokee transmission input & output speed sensors. Did we mis anything? Please get in touch with us and tell us about it!

Speed sensors location on the 45RFE / 545RFE transmission.

The Input and Output Speed Sensors are two-wire magnetic pickup devices that generate AC signals as rotation occurs. They are mounted in the left side of the transmission case and are considered primary inputs to the Transmission Control Module (TCM).

Note:
The 42RE transmissions use a single sensor (located on the overdrive gear case, over the park gear).The 45RFE / 545RFE transmissions use two sensors, an input speed sensor and an output speed sensor. Both are the same part number.

Operation:

The Input Speed Sensor provides information on how fast the input shaft is rotating. As the teeth of the input clutch hub pass by the sensor coil, an AC voltage is generated and sent to the TCM. The TCM interprets this information as input shaft rpm.

The Output Speed Sensor generates an AC signal in a similar fashion, though its coil is excited by rotation of the rear planetary carrier lugs. The TCM interprets this information as output shaft rpm.

The TCM compares the input and output speed signals to determine the following:

Transmission gear ratio
Speed ratio error detection
CVI calculation

The TCM also compares the input speed signal and the engine speed signal to determine the following:

Torque converter clutch slippage
Torque converter element speed ratio

Sensor failure:

Failure of the Transmission Input Shaft Speed Sensor and/or the Output Shaft Speed Sensors are somewhat common on early model WJ Grand Cherokees. Diagnostic Trouble codes that may be tripped are:

P0500 – No vehicle speed sensor signal

P0720 – Low Output SPD Sensor RPM Above 15 MPH
The relationship between the Output Shaft Speed Sensor and vehicle speed is not within acceptable limits.

P0720 – Low Output SPD Sensor RPM Above 15 MPH
Output shaft speed is less than 60 rpm with vehicle speed above 15 mph (4-speed auto. trans. only).

P0721-P0723 – Sensor circuit range, performance, no signal

Speed sensor removal

1. Raise vehicle.
2. Place a suitable fluid catch pan under the transmission.
3. Remove the wiring connector from the input speed sensor.
4. Remove the bolt holding the input speed sensor to the transmission case.
5. Remove the input speed sensor from the transmission case.

Speed sensor installation

1. Install the input speed sensor into the transmission case.
2. Install the bolt to hold the input speed sensor into the transmission case. Tighten the bolt to 105 in.lbs. (11.9 N·m).
3. Install the wiring connector onto the input speed sensor
4. Verify the transmission fluid level. Add fluid as necessary.
5. Lower vehicle.

WJ speed sensors
Output speed sensor for 42RE transmission (1999-2004)	P/N 4800879 (supercedes P/N 4412879)	List price: $18.35
Input speed sensor for 45RFE / 545RFE transmission (1999-2005)	P/N 4799061AB	List price: $36.70
Output speed sensor for 45RFE / 545RFE transmission (1999-2005)	P/N 4799061AB	List price: $36.70

(Prices listed are for reference purposes only and may vary by dealer. Parts are not available from this web site.)

Joined Nov 14, 2014

2 Posts

Discussion Starter · #1 · Nov 14, 2014

Hi first and thanks for the site. I've been an avid reader for many moons now and have really never needed to ask for help till today.

My check engine light came on so I took it to O'Reillys and it came back with ERROR code P0700 and said "Speed Input/Output sensor not respoding" or something in that neighborhood. Now after looking into it on Jeepforums that's a generic code for transmission problems but I confirmed it on how it drives. Sometimes when I come to a stop and try to take off it will have a winding sound and no drive at all, like its not in 1st gear but in 3rd or 4th(does it more and more offen then not). In other instances it wont switch from 2nd to 3rd/3rd to 4th and so on...(Stuck in whatever gear its in).

Looked up excatly how to swap out my speed sensor, including the location and the correct part but when I got underneath my Jeep there was NO speed sensors in the locations I learned of on the forums... So now I'm trying to figure out where else it might be. I've checked google and it seems I cant track down the location of my current transmission. I think the problem is I do not have the same transmission that usually come with this model. Not sure if previous owner had to replace it or what. Ive got 3 no. on it T12TJ252560560, P52108421AB & 421 AB. It appears that other jeeps have the 45 RFE.

Any help would be greatly appreciated

2006 Jeep Grand Cherokee Laredo V6 3.7L

Joined Jan 25, 2013

3,502 Posts

Your Jeep has the Mercedes NAG1 trans. Only 4.7 and 5.7 WK's have the 5-45RFE trans.

Joined Nov 14, 2014

2 Posts

Discussion Starter · #3 · Nov 14, 2014

Your Jeep has the Mercedes NAG1 trans. Only 4.7 and 5.7 WK's have the 5-45RFE trans.

Thank you caulk04 for your swift reply. I've been beating my head against the wall. Now that I got confirmation on the transmission which is a Mercedes NAG1 722.6 transmission(Correct?)

Found this conductor plate. Is it the correct one for my transmission? Do not want to get the wrong one $$$.

http://www.ebay.com/itm/Genuine-OEM...Parts_Accessories&hash=item4181737eed&vxp=mtr

Joined Jan 25, 2013

3,502 Posts

I don't know much of anything about the trans. I just know it's fitted to 3.7, 3.0 and 6.1 engines in these Jeeps and it has lower gear ratios than the 545RFE.

Joined May 12, 2014

198 Posts

Theres a mercedes guy on youtube, pretty sure if you search 722.6 you will see him, and he has a video that shows exactly how to change that plate. This is not a job for beginners.
Aside from that he also outlines the whats and whys about that tranny, and if I recall correctly changing the fluid in a 722.6 can fix ALOT of shifting issues.

Where is the transmission speed sensor?

Note: The transmission speed sensor is located in the rear of a longitudinal mount transmission. For transaxles, the speed sensor is located on the long side of the output shaft. This would be the end of the transaxle that faces the front of the engine.

What happens when your transmission speed sensor goes out?

When there's no speed signal coming from the sensors, shifting of gears will be a problem because the powertrain control module won't control them correctly. This will make the transmission not work properly. It will either shift more quickly or roughly than expected.