Transmission Not Shifting?

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?

Yup! Its the speed output sensor. was about $70 to fix.

thanks.

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

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.

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.

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.

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!

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).

[quote:f0c05360aa="BMRFIXIT"]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).[/quote:f0c05360aa]

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

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

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...

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.

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.

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.

sometimes it will not shift into fourth gear.

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.

Yes I appreciate your help. I checked all the things you said to do, but it still won't shift into 4th.

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.

Thanks, I appreciate the help.

Thank you for using 2CarPros.com. Tell your friends, family and anyone you like about us and please return with any auto related questions, we're here to help.

okay, on the twenty fourth of this month my vehicle shifted fine. I come home washed it and pressure washed underneath it and now will not shift at all from second. will not go in to drive or third. it calls for a first and second gear sensor.

pressure washing is the enemy of today's computers . pull connections on ECM and TCM and check for water intrusion. if it does try a hair dryer on connections then smear dielectric grease on there and see what happens . do same at transmission as I am assuming this is an automatic transmission. finally if it continues look for broken wires at transmission and scan for codes. also, because it is a 4.0L check for harness hitting back stud of engine bolt and grounding out.

i had it scanned by a friend he came up with code 1747,he said it was a shorted shift selenoid b,i got 1 from a boneyard,put it in,didnt cure,could it be a shorted wire or something else,cant afford a mechanic,i must do this myself
any help will help
ty tom

Hi Tom,

Here are the diagnostic procedures.


TC-179A

1. If DTCs P1745 and P1749 are set in addition to DTC P1747, repair faulty transmission case ground. If specified DTCs are not set, go to next step.

2. Using scan tool, record, then clear TCM DTCs. Raise and support vehicle. Place gearshift lever in "D" (Drive) position and accelerate to 55 MPH using light throttle. Repeat procedure 2 more times from zero MPH. If DTC P1747 resets, go to step 4). If DTC P1747 does not reset, go to next step.

3. Conditions necessary to set DTC P1747 are not present at this time. Inspect condition of related wiring and harness connectors. Repair as necessary. If no problem is found, go to DIAGNOSTIC AIDS

4. Turn ignition off. Disconnect transmission solenoid harness connector. Using a DVOM, measure resistance between ground and solenoid No. 2 control circuit (Dark Blue/White wire) at transmission side of harness. If resistance is less than 20 ohms, go to next step. If resistance is not as specified, go to step 7) .

5. Disconnect TCM harness connector. Turn ignition on. Using a DVOM, measure voltage between ground and solenoid No. 2 control circuit (Orange/White wire) at TCM harness connector. If reading is greater than one volt, repair Orange/White wire for a short to power. If reading is not as specified, go to next step.

6. Turn ignition off. Using a DVOM, measure resistance of solenoid No. 2 control circuit (Orange/White wire) between transmission solenoid harness connector and TCM harness connector. If resistance is less than 5 ohms, replace TCM. If resistance is not as specified, repair open in Orange/White wire.

7. Remove transmission oil pan. Disconnect solenoid No. 2 harness connector. Using a DVOM, measure resistance between ground and terminal of solenoid No. 2. If resistance is less than 20 ohms, repair open in solenoid No. 2 control circuit (Dark Blue/White wire). If resistance is not as specified, replace solenoid No. 2.


Diagnostic Aids
Visually inspect related wiring and harness connectors. Check for broken, bent, backed-out or corroded terminal pins. Check for wires that are chafed, pierced or partially broken inside insulation. Repair as necessary. If no problems are found, refer to any Technical Service Bulletins (TSBs) that may apply.

© 2008 Mitchell Repair Information Co., LLC.

1996 Jeep Cherokee Sport, 4.0 six, automatic, Transmission has had no problems at all until recently will not down shift back to 1st when stopping. Manually take off in 1st then shift and goes directly to 3rd. Changed tranny filter and 4 qt. fluid. did not help.I have never had any issues with it at all.

Is the check engine light coming on?

Could be a valve body and a shift solenoid problem-have it pressure tested to find out more what's going on

check engine light is not on. tranny was also flushed at approx. 150000 miles

could be a bad governor as it will control downshifts and upshifts. you need a trans guy to help you. this is beyond fluid servicing.

Roy

thank you for your assistance. travis

Your welcome

1991 Jeep Cherokee almost 200,000 miles with an automatic 4.0 L I6. My baby runs strong but won't shift until 3,500 RPMs hen under normal acceleration. The harder I step on the accelerator, the high the RPMs climb before it will shift. This happened all of a sudden and normally shifts at around 2,000 RPMs when I'm not passing someone or pulling out into heavy traffic. Please help.

may be a shift solinoid in tranny...

Turned out to be the TPS, funny, a code for the TPS never came up, but there you have it.

I have a 1988 Jeep cherokee laredo four door with a 4.0 Inline six cylinder with four wheel drive. It had been sitting undriven for about nine months, and before I started driving it again I gave it a tune up changed the oil, plugs, wires, cap, rotor, fuel pump, fuel filter, also the map sensor. When I started driving it, it had a very high idle, so I replaced the Idle air control motor, that didnt work so I temporarally fixed the high idle by extending an old IAC valve to plug the hole in the throttle body, and disconnected the electrical connection, which gives it a low idle, when cold but it is functional. I dont know if the high idle is related to the transmission issue which is my main question. When starting from a dead stop and accellerating the transmission shifts through all the gears up to overdrive, before 30-35mph even at full throttle. After it is in overdrive, It wont downshift even at full throttle. I checked the transmission fluid and it was fine. Your help would be greatly appreciated.

When I had high Idling. It would be reving itself up. As soon as you start it? There was a hole in my air intake manifold. It never did it since I replaced it.

When I first start the Jeep, transmission shifts well. As the engine heats up, the transmission stops shifting until it reachs a point where the car won't even move. Once it cools down it will shift until car heats up again. Any idea what might be the cause?

Hi glennbenjamin, Welcome to 2carpros and TY for the donation

Do you have a check engine light?

Check the transmission fluid level and condition if okay -bring it in and have it pressure tested this will indicate what's going on with it-could be a throttle and governor pressures are low,sticking shifting solenoid, torque converter and valve body etc

Recently my jeep has developed a problem that sometimes in D automatic it will not change gears properly. I can drive it in 1/2 , 3 and then onto D/4 fine but if I pull up and try to start in D it revs but doesn't move - it almost seems like it is in 4th. The problem seems to happen after 20 min or more of driving and usually stays like that until it has rested for a while but sometimes it will start to work as normal again after a while. It seems to be getting like this more each day though.

$th gear is applied electrically using an overdrive solenoid switched by the Powertrain Control Module. If the fluid smells ok and looks ok it may be electrical in nature and the torque converter or hydraulic valves may be at fault. Sorry but it must be tested with a scan tool to eliminate what is ok, and pinpoint what the problem is. If the fluid smells burnt, it will need repair or replacement. An input to the Pcm may be at fault also. Check the fluid so if it is the worst news at least you will know they are not trying to do a repair that isn't neccesary. High mileage, 16 years old so be prepared for anything. At least you will know how to make the right decision if you have it serviced by the manufacturers dealer technician. Good luck. You could just keep it out of overdrive and use it like that for a short time also but the fluid tells the story. Goodbye