matt_101

Hey guys,


I'm having a problem wiuth my 98 grand cherokee lardedo.... it's always shifted a little funny, i adjusted the kick down cable a few months ago its shifted much better since that.

I parked it last night and when i came out this morning and pulled out of the driveway, it wouldn't shift out of first gear. I've read that the TCU could be the problem, does the 98 grand have a TCU? i thought everything was done in the PCM (powertrain control module). There is a new PCM in jeep.

I checked the fluid, it looked low - so i topped it up.... but it still won't shift out of first. I'm stumped because it shfited okay last night when i parked it lol.... werid.


Where should i start looking? My kickdown cable has already been adjusted.


what do you guys think?

-TCM, how do i check this/where is it loacted on a 98 grand?
-TPS
- Transmission itself
-What else should i check?

Help very much apperciated!

matt_101

I just checked the codes and this is what i got:


P0720 Output Speed Sensor Circuit Malfunction



Where is the speed sensor on this vechile?

matt_101

I'll replace the speed sensor and update if that fixes my problem.



Anyone care to chime in here?

matt_101

So apparantly there are 2 speed sensors on this vechile...... could somebody PLEASE tell me which one is the output sensor and witch is the input?

TonyZJ

The output speed sensor in located on the left side(drivers side)at the rear of the tranmission. The input speed sensor is located in the front of the transmiison on the left side as well, and yes both speed senors are interchangable. This information is for a 1998 Jeep Grand Cherokee Laredo with the 4.0 (6 cyl). The speed sensor costs around $26.00 at auto zone. The senor screws in and out, just make sure you have a catch pan to catch the transmission fuild that will come out.

And do yer self a favor and DON'T reuse the the fuild that came out of the transmission!!! Transmission oil is cheap compared to repairing a transmission.

Hope this helps someone out.....

Got this from Google

matt_101

I ordered the sensor today...... hopefully i got the right one. I never pulled the old one out yet as i couldnt find a diagram......

Can anyone show me a picture of what this sensor looks like so i can see if i orded the correct one?

This is what the one i ordered looks like:

http://cgi.ebay.ca/SC105-Speed-Senso...DLVI%26ps%3D63

ol"blue

You have a vehicle speed sensor and a transmission output speed sensor. The attached pics might help you with the transmission speed sensor.

OverlandZJ

ol'blue beat me to it.. but i'll add this anyway. Different diagram.

http://www.jeepforum.com/forum/f310/...ensors-287793/

matt_101

The sensor i bought looks like the one pictured in that theard... ie: you slide it in and a bolt holts it in place......

but the diagram from old blue shows a different sensor that appears to be threded itsself.

lol...... guess we'll find out tomrrow, i had the part overnighted.

ct67_72

make sure your looking at the back of your tranny and not your transfer case. it may have a different sensor back there also.

jnicewan

The sensor you need is threaded, it screws into the trans in the O/D unit housing. its a couple inches behind the pan and on the drivers side, pointing slightly downward.


Here is a pic of the sensor you need.



Here is a pic of the one you do not need, I included this one just for reference. This sensor is on the back of the transfer case and its primary functions are: speedometer, speed control.

matt_101

CRAP!

guess i'm stuck with a sensor i dont need then..... special order item.


What is the name/part number of the one i need? I asked for an output speed sensor and the guy at the parts store ordered the one that i don't need......

ct67_72

the only place I have found the correct one other than my trans parts supplier is autozone

jnicewan

It is the output shaft speed sensor. Not vehicle speed but output shaft speed.
The wrong sensor, which they ordered for you does not even go on the transmission
Chrysler also calls the vehicle speed sensor something like "distance" sensor but the confusion should have been eliminated with using "output" vs "vehicle" speed sensor.
I think aftermarket might call them "transmission speed sensors" its still not "vehicle speed"

I can be kind of an *** about stuff like this, but I would tell the parts guy to take it back one way or the other. He is the one that ordered the wrong part. They can take it back, they just dont want to. You could always keep it around for a spare though I guess.

I dont know if this link will work, but I looked up the correct part at O-reilly's. You can have your parts guy try to get this part number or see if he can cross it over too.

Dorman Part # 917-602

http://www.oreillyauto.com/site/c/de...n+speed+sensor

matt_101

I picked up the correct one from the dealer, the jeep shifts like a new vechile now. Thanks guys. (especialy old blue )


- now to try and return the one i don't need. My parts guy is usually pretty good..... hopefully it wont be too much of hassel getting him to take it back.