Transmission Not Shifting?

Tiny
FTSESQ
  • MEMBER
  • 1999 JEEP CHEROKEE
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 98,000 MILES
Hi there. I have a '99 Jeep Grand Cherokee with about 98000 miles on it. I’ve owned it since 25000 miles, and aside from a water pump at 64000, it has been trouble free- just routine maintenance. However, yesterday the transmission started acting up. It seems like it won’t up-shift out of first, but when I take my foot off of the gas, the RPM’s drop back to idle and it coasts like it’s in neutral. It’s strange because there had been no previous slipping or stuttering from the trans, it just happened yesterday morning. The first time, it did this it only lasted for about a ¼ mile, then I stopped at a red light. When I left the light it shifted into second at around 2200 RPM’s just like normal. Then when I was leaving work, it did it again, but would not fix itself. I stopped at a gas station to check the fluid, and it was right on full. I started it to try to limp home and like magic, it worked fine. Shifted like normal. This morning, it did it again. This time, I checked the fluid with the engine running and the trans in neutral, and the fluid level was under the “min" mark, so I added about a quart of fluid, but it did not help. So, I was on the way to the mechanic when I stopped for gas. Pulling out of the gas station… You guessed it. It shifted right around 2200 RPM’s into second, and worked fine from there on out. I didn’t go to the mechanic because I was already late for work, but I’m worried now. What do you think is causing this, and more importantly, how muck do you think it should cost to fix?
Any help that you could offer would be greatly appreciated.
Thank you,
Fred
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Friday, June 11th, 2010 AT 3:36 PM

52 Replies

Tiny
1999JEEPGC
  • MEMBER
Hey I have the same problem. On the same model and year. Mine changes into 2nd at around 2500 RPM when pulling away for the first time but then works fine. It does it after I park somewhere and first put it into D.

Did you ever figure out what the problem was?
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Friday, August 13th, 2010 AT 2:13 PM
Tiny
FTSESQ
  • MEMBER
Yup! Its the speed output sensor. Was about $70 to fix.
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Friday, August 13th, 2010 AT 3:31 PM
Tiny
1999JEEPGC
  • MEMBER
Thanks.
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Friday, August 13th, 2010 AT 4:18 PM
Tiny
GARYLEONPERKINS
  • MEMBER
  • 1998 JEEP CHEROKEE
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 168,000 MILES
My son bought it for $100.00. So far the battery, radiator, has been replaced as well as the spark plugs, and plug wires, rotor and distribitor cap and oil, filter change. It starts up fine and idles fine but take it on the road and it will not shift from second to third unless you let it coast back down to 30mph and then you can feel it shift into 3rd and then into OD. Sometimes you drive it slowly building up speed and it will do okay. But once you stop it idles rough. The Fluid level is right, does not look like it has been changed in a long time. I thought maybe a vacuum hose or maybe change the transmission filter
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Tuesday, November 12th, 2019 AT 2:58 PM (Merged)
Tiny
RACEFAN966
  • EXPERT
Ok there is no vacuum to the transmission it is electronically controled. This control comes from a couple of sensors one is temp of the trans and the other is the TPS. Now if this has been sitting a long time then I would first do a trans service which is changing the fluid and filter and put in either the lucas trans additive or the lube guard additive. Make sure you get the atf +4 fluid other then that. Let me know what you want to do from there.
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Tuesday, November 12th, 2019 AT 2:58 PM (Merged)
Tiny
KPKMMA
  • MEMBER
  • 1997 JEEP CHEROKEE
  • 4.0L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 149,000 MILES
Mil came on while driving and stopped down shifting to 1st. Scanned w/ cheap scanner and found p0700 stored. Cleared code and drove for a few days until mil came on again and problem returned. Repeated this procedure several times and found that with mil off, downshift was normal most of the time and with mil on there was no downshift almost all the time. Finally had it scanned w/snapon scanner to find code p1747 stored. I know there is a specific diag. Procedure for this code, but now the mil is on all the time and when I scan it there are no codes stored. To drive it I have to shift manually. I was wondering if the pcm or tcm might be bad and am thinking of having it scanned again.
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Tuesday, November 12th, 2019 AT 2:58 PM (Merged)
Tiny
HMAC300
  • EXPERT
There is no 1747 code but there is a 1757 which will probably give you your problem. Have a trans guy use his scanner as he needs to drive with scanner connected to read governor pressures as it may be a bad solenoid or valve body problem. What this code is that there is pressure going to the governor when stopped and there shouldn't be. So it can really be a multitude of things. Causing this. But you need a pro style like the snap on one to see what is going on.
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Tuesday, November 12th, 2019 AT 2:58 PM (Merged)
Tiny
JADAMSON
  • MEMBER
  • 1997 JEEP CHEROKEE
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 230,000 MILES
I have a 1997 Jeep Grand Cherokee that seems to have a very similar problem as most people are having. My jeep will shift into 1st and second okay but when it does to third I have to rev the engine up to high rpm's before it clicks over, and usually more than one time. When its cold its worse. Now, when I try to go in reverse I have to start the car, let it warm up for a sec and then shift into reverse, sometimes its smooth and sometimes I have to rev the engine to make it jerk into reverse. The engine light is on and the trouble code is 37 and the OBDII code is p0740 or something to that effect. Please help!
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Tuesday, November 12th, 2019 AT 2:58 PM (Merged)
Tiny
BMRFIXIT
  • EXPERT
1st step with this code should be removing and replacing the output speed sensor
i would replace the input and output sensor

P0740 OUTPUT SPEED (OS) SENSOR
The OS sensor is mounted in adapter housing or extension housing. The OS sensor is an input device consisting of a speed sensor rotor and speed sensor. Speed sensor rotor is mounted on transmission output shaft. Input signal is delivered from OS sensor to TCM with each revolution of transmission output shaft. The TCM uses input signal for controlling transmission operation (shift points and TCC engagement).
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Tuesday, November 12th, 2019 AT 2:58 PM (Merged)
Tiny
JADAMSON
  • MEMBER
First I thank you for your help. If this does fix my car I plan on donating more money to help you guys out.

I do have a question though. When I looked up P0740 it talked about "Relationship between engine and vehicle speeds indicated failure of torque convertor clutch lock-up system (TCC/PTU sol)." Will the (OS) sensor fix this problem also? For $18.00 at my local Autozone it is worth a shot and I will try it at least. I just want to make sure we are talking about the same thing.

-Jason
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Tuesday, November 12th, 2019 AT 2:58 PM (Merged)
Tiny
BMRFIXIT
  • EXPERT
Remove transmission oil pan and check for burnt oil or debris. If excessive debris and/or burnt oil is present, repair internal transmission problem
if not replace sensor and road test
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Tuesday, November 12th, 2019 AT 2:58 PM (Merged)
Tiny
CRONOS1
  • MEMBER
  • 1996 JEEP CHEROKEE
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 200,998 MILES
Drove to work, drove home from work would not shift out 1st gear. No mater what I did. Later that day went to store car worked just fine. Then about two weeks later, same thing but now will not come out of 1st no matter what I do. Can you help? Thanks. MIKE.
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Tuesday, November 12th, 2019 AT 2:58 PM (Merged)
Tiny
BMRFIXIT
  • EXPERT
I would suspect a speed sensor
best to do have the codes checked
SPEED SENSOR test
Disconnect electrical connector at speed sensor located on adapter housing or extension housing.
Connect ohmmeter leads between speed sensor electrical terminals.
Rotate transmission output shaft and note ohmmeter reading.
Ohmmeter needle should fluctuate to indicate speed sensor operation.
Replace speed sensor if no reading is obtained.
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Tuesday, November 12th, 2019 AT 2:58 PM (Merged)
Tiny
GENERALMARTOCK
  • MEMBER
  • 1999 JEEP CHEROKEE
Transmission problem
1999 Jeep Cherokee 4 cyl Four Wheel Drive Automatic 150k miles

To whom this may concern, I've been a mechanic for over 35yrs. However during the early 90's I gave it up to become an O/O of an 18 wheeler.

Today (07/08/09) a friend asked me to check out his son's (James) 1999 Jeep Cherokee Laredo. It has a 4.0L 6cyl engine, 4 X 4 automatic transmission with a 14 bolt pan.

I took it for a test run and it won't shift out of 1st gear.
I dropped the pan (I noticed tranny fluid the inspection plate and trans body. Front main leak) and removed the filter. It was filthy and plugged up. I looked in the pan itself and there wasn't any chunks of medal, nor any clutch material. The magnet has a small amount of matter on it and it didn't feel sandy. The tranny fluid didn't smell burnt and appeared the color was ok.

I looked inside and didn't see any broken wires or anything weird.
I cleaned up the pan and tranny body, installed a new filter and gasket and poured in approx, 4.5 quarts of ATF+4.

Took it out for another test run and still the same problem.
As I was doing all this I was asking James how long the tranny was acting up. He danced around the question but, I finally got him to admit the tranny has been losing fluid since the 1st of the year and it d slip until he d toss in 3 or 4 quarts.

I believe the tranny is blown. However, since I haven t any test equipment to check out the electronics, it is possible a relay or a computer problem is the cause. Are there any tests I can perform w/o any expensive test equipment? I have test lights and a multi-meter.

Any help will be appreciated.

Thank you
Shal aam
AAPiY
Mike

P.S, until this economy improves, all I can afford to donate (at this time) is $5.00.
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Tuesday, November 12th, 2019 AT 2:59 PM (Merged)
Tiny
RACEFAN966
  • EXPERT
Ok here is how it works. The PCM (Power Control Module) determines the shift points and when it shifts with the help of the trans fluid temp sensor, the output shaft speed sensor, the crank shaft position sensor, the vehicle speed sensor, the throttle position sensor and finaly the battery temp sensor. There are 4 governor pressure setting programmed into the pcm for different temps and throttle openings. So what I would do first is get some answer as to how it has been running and maybe test the TPS first to see if it is reading right. Then I would check the governer pressure and temp sensor (the same sensor) in the trans here is a pic of it and if you need I can get the test procedures. Let me know what you need from here.


https://www.2carpros.com/forum/automotive_pictures/249564_Graphic_100.jpg

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Tuesday, November 12th, 2019 AT 2:59 PM (Merged)
Tiny
HICKMAN 1
  • MEMBER
  • 1995 JEEP CHEROKEE
  • 4.0L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 253,000 MILES
Sometimes it will not shift into fourth gear.
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Tuesday, November 12th, 2019 AT 2:59 PM (Merged)
Tiny
STEVE W.
  • EXPERT
Few things to check.
When was the last time the trans was serviced (new fluid/filter)?
Is it full of fluid? Do you have any other issues relating to engine performance? This question is because the TPS provides information to the transmission control module.

The transmission in your Jeep is fully electronically controlled. One of the common items that can cause this issue is a dirty transmission gear switch aka the neutral safety switch. It is possible to clean this. Write up on that process and testing-
http://www.boyandjeep.com/tech-articles/aw4-neutral-start-switch-rebuild

Next, check the trans control cable adjustment at the throttle body.
-Open hood while vehicle is off in park.
-Find TB.
-Press and hold the transmission cable release button.
-While holding cable release button push conduit into the ratcheting cable release button.
-Hold conduit in.
-Release the cable release button.
-Open TB to wide open and the button will automatically ratchet and lock into the correct place.

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Tuesday, November 12th, 2019 AT 2:59 PM (Merged)
Tiny
HICKMAN 1
  • MEMBER
Yes I appreciate your help. I checked all the things you said to do, but it still won't shift into 4th.
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Tuesday, November 12th, 2019 AT 2:59 PM (Merged)
Tiny
STEVE W.
  • EXPERT
Then you will need to use a good scan tool to run the service tests on the transmission and see where the problem is. There is no real mechanical controls to adjust or test just the electronics.
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Tuesday, November 12th, 2019 AT 2:59 PM (Merged)
Tiny
HICKMAN 1
  • MEMBER
Thanks, I appreciate the help.
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Tuesday, November 12th, 2019 AT 2:59 PM (Merged)

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