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Chris (aka- Moose)
Chris (aka- Moose), Technician
Category: Transmissions
Satisfied Customers: 1764
Experience:  16 yrs. experience with auto, manual, & CVT drivelines
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I have a 2001 Dodge diesel with a 46 Re: and it will not

Customer Question

I have a 2001 Dodge diesel with a 46 Re: and it will not shift into first or overdrive when it's cold after it warms up I turn it off and restart it everything works great
JA: How old is the transmission? Have you noticed any leaking?
Customer: It's not leaking and I just recently replaced and lock out converter and all the solenoids in the valve body
JA: What is the model of your '01 Dodge?
Customer: It's an SL or a sport model it has the 24 valve motor and a 46 are you tranny and it's four-wheel-drive
JA: Are you fixing your SL yourself? What have you tried so far?
Customer: Yes I am and what I guess the next step is to a drain the fluid and check the overdrive so annoyed to make sure it's working properly other than that all I can guess is if there's a problem with the PCM
JA: Anything else you want the mechanic to know before I connect you?
Customer: No
Submitted: 11 months ago.
Category: Transmissions
Expert:  Reggie Whiddon replied 11 months ago.

Hi im Reggie thanks for using JustAnswer. Put my years of experience and training to work for you

Expert:  Reggie Whiddon replied 11 months ago.

Hello and thanks for question. You say it want shift into first, is it starting off in second and not shifting? The first thing I would do is verify a good voltage source at the transmission, because if you lose power by default it operates in second gear. Also dont drop the pan since you have already replaced the solenoid pack we need to access the pcm and check resistance of each of those solenoids at the pcm connector that way were checking the wiring and the connector at the trans.

Expert:  Reggie Whiddon replied 11 months ago.

1. Check the governor pressure sensor voltage Key On Engine Off (KOEO). It should be about 0.5 -0.7 volts.

2. Monitor the desired governor pressure. If that goes higher along with vehicle speed, the Output Shaft Speed (OSS) sensor is working OK.

3. If the OSS sensor is working OK, replace the governor pressure solenoid.

Tech Tips:The OSS sensor is used by the Powertrain Control Module (PCM) to control the governor pressure. The governor pressure sensor is monitored by the PCM, so the PCM can achieve the desired governor pressure. As the output shaft speed increases, the duty cycle to the governor pressure solenoid will come down. The pressure comes up creating the upshifts.

Expert:  Reggie Whiddon replied 11 months ago.
1. Remove the transmission relay from the Power Distribution Center (PDC) and jumper terminals 30 and 87.

2. Check for B+ on pins 8, 11 and 21 in the center Powertrain Control Module (PCM) connector.

3. If no voltage is present on any of the three pins, check for an open circuit or solenoid. The overdrive and Torque Converter Clutch (TCC) solenoid should be 25-40 ohms and the governor solenoid should be 3-5 ohms.Tech Tips:The Powertrain Control Module (PCM) turns the transmission relay off when it detects an electrical problem with the solenoid circuits. This is limp-in and causes governor pressure to go high causing the transmission to stay in 3rd gear when the transmission is in drive.
Customer: replied 11 months ago.
Ok Let's start over when it is cold wants to start in 3rd after it gets to operating temp I turn it off restart it and it shifts just fine all gears. By the way I jumped trans relay and had voltage to all three pins 8,11,21
Expert:  Reggie Whiddon replied 11 months ago.

Okay lets look at this. Have you scanned the module for any codes? Having a code would give us a good starting point.

Expert:  Reggie Whiddon replied 11 months ago.

. Check the resistance of the Output Shaft Speed (OSS) sensor. It should be 500-750 ohms.

2. Inspect the wiring harness between the OSS sensor and the Powertrain Control Module (PCM).

Tech Tips:The speedometer gets vehicle speed from the rear axle speed sensor. The OSS sensor is only used to control governor pressure in the transmission

Expert:  Reggie Whiddon replied 11 months ago.

Do you have a scan too? Voltmeter? Have you tried swapping the trans relay with another known good relay? They are a common item to fail espicially if you had a solenoid pack go out its a good idea to replace with new. the 3-4 solenoid if it is open or shorted the pcm will cut the ground to relay causing power loss. the oss if it is open you would not know it other than your shifting problem. And finally the pcm ive had multiple failures of the pcm the quad driver that turns the trans relay on fails. but being that this problem is temperature sensitive lets look at the solenoids and the sensor.

Expert:  Reggie Whiddon replied 11 months ago.

Good morning I will be on here all day will be checking in with you

Customer: replied 11 months ago.
I have changed all solenoids and both speed sensors but when I changed speed sensor my speedometer now is irratic my old sensor was better to bad I threw it away
Customer: replied 11 months ago.
I have a scan tool give me a P0753 and I have a voltmeter and an ohmmeter I have changed relays but where my problem is I get no voltage to the relay until it's at operating temperature
Expert:  Reggie Whiddon replied 11 months ago.

hi okay let me reveiw the code

Expert:  Reggie Whiddon replied 11 months ago.

Okay you say that you are not getting any voltage from relay until the truck warms up. Then you most likely have a faulty pcm we can check that by removing the relay and check the voltage on pins 85 and 86one of those will be voltage with key on the other will be a ground provided by the pcm. And for the pcm to fail and not provide that ground is pretty common. Easy to check just when its cold remove relay and see if you have voltage with your leads on 85 86

Customer: replied 11 months ago.
With The key on number 30 has 12V. and 85 ,86 and 87 are all grounds
Expert:  Reggie Whiddon replied 11 months ago.

Okay now we know our problem. YOur pcm is not energizing the trans relay.

Expert:  Reggie Whiddon replied 11 months ago.

The most likely cause of this is a faulty pcm. But to be sure you can check all the powers and grounds to the pcm if they are all good we can check for the relay command directly at the pcm if not present. YOu need to replace the pcm