Replacing the Transmission Speed Sensors

jellyroll · 06-28-2006, 07:38 AM

I got a $350 quote yesterday for replacing the input and output speed sensors on my 1999 Grand Cherokee. This quote includes the $100 scanner diagnostics test.
After browsing the archives here, I learned that people have paid roughly $180 total to replace the sensors.

How hard is it replacing the sensors? Its just a bolt and a bracket?

Since I already have $100 invested, I may just suck it up and pay the $250 balance. But at the same time, I'd rather do it myself save couple bucks and learn a thing or two.

rm2001wj · 06-28-2006, 08:09 AM

It would be easier than changing a flat. See this link for sensor locations and instructions. (BTW, very little fluid leaks out when a sensor is removed.)http://www.wjjeeps.com/speed_sensors.htm

jellyroll · 06-28-2006, 09:04 AM

I did see that link but I am also going to purchase the Chilton just in case.

Thanks rm2001wj

AnDaCo2002 · 06-28-2006, 10:14 AM

I bought both sensors a couple weeks ago from the stealership for $87 and some change. It literally took less than 10 minutes to change them myself. It is soo much easier and faster than changing a flat tire.

jellyroll · 06-28-2006, 10:19 AM

Thanks for the reassurance AnDaCo2002.

This may seem like a dumb question but...

1) How do I know if I need a "WJ Speed Sensor?" What is "WJ?"

2) How can I find out which transmission I have? (42RE or 45RFE)

rm2001wj · 06-28-2006, 10:24 AM

WJ = 1999 - 2004 Grand Cherokee

It's always good to tell what engine you have. Anyway the 4.7L V8 has the 45/545RFE, while the 4.0L I6 has the 42RE. The 42RE has only one, an output speed sensor.

jellyroll · 06-28-2006, 10:39 AM

Interesting... I have a V6 4.0 but the quote I got was for (1) input sensor and (1) output sensor.

Perhaps I need (2) output sensors?

Quote:

Originally Posted by rm2001wj

WJ = 1999 - 2004 Grand Cherokee

It's always good to tell what engine you have. Anyway the 4.7L V8 has the 45/545RFE, while the 4.0L I6 has the 42RE. The 42RE has only one, an output speed sensor.

EDIT:
Just got off the phone with Jeep parts. They said that there are 2 sensors and both have the same part # Apparently they are universal.

jellyroll · 06-28-2006, 11:04 AM

One last thing if I may,

Will the output sensor on the 42 RE be in the same location on the 45/545RFE as shown on the diagram below?

Thanks again..

rm2001wj · 06-28-2006, 12:58 PM

Quote:

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

As you can see in the above quote from wjjeeps.com, the single 42RE sensor is different from the two 45/545REF sensors. They are not universal! The 42RE sensor is in a similar approximate location as the 45/545RFE output speed sensor. However, it screws directly into the transmission case instead of being held in place by a bolt.

It seems like either you and the Jeep dealership are not communicating very well or that they are trying to screw you. Maybe you should try another dealership.

BTW, the six cylinder engine is a straight or inline six (I6), not a V6.

jellyroll · 06-29-2006, 05:00 PM

I replaced the sensors and the problem is fixed! Thanks for everyones support here.

Now I need to reset the check engine light. My service manual states:
"After the system has been repaired, the codes must be cleared fro mthe PCM memory using the scan tool (i do not have) Do I need to take it to the dealer to have the codes cleared?

**10achik** · 06-29-2006, 05:26 PM

Unhook your battery for about 20 minutes.

jellyroll · 06-29-2006, 05:39 PM

I just found a few threads about unhookung the battery.
My service manual says "Do not disconnect the battery"
Not sure why it says that but it seems to work for eveyone here...

Thanks to everyone here for all the replies.

**Phil Gerard** · 06-29-2006, 07:04 PM

Quote:

Originally Posted by jellyroll

I just found a few threads about unhookung the battery.
My service manual says "Do not disconnect the battery"
Not sure why it says that but it seems to work for eveyone here...

Thanks to everyone here for all the replies.

Your service manual also says to bring it to the dealership for all service work.
Remember who wrote it.
Also, the check engine light should go out but the codes may remain until you cycle the GC on and off about 20 - 50 times. So, don't be alarmed unless the check engine light comes on and then pull up the codes yourself and save $100. Instructions in the FAQ Stickey Thread above.

Phil

**Virmagicus** · 06-29-2006, 07:11 PM

Nice work Jellyroll

jellyroll · 06-29-2006, 07:30 PM

So I unhooked the negative termainal and waited over an hour but the check engine light still comes on.
I turned the car off and on- sometimes holding the reset button by the sunroof- 3 times but the light still appears.

I will look through the instructions in the FAQ Stickey Thread that Phil mentioned.
Thanks again.