Transmission's third gear not working?

2007 DODGE RAM
432,000 MILES • 4.7L • V8 • 2WD • AUTOMATIC
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CHRISTIAN CHENARD
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My Canadian truck listed above 1500 with 545rfe transmission, 2wd won't go in third gear (go neutral). all this happened all of a sudden "one day the truck was driving fine, was parked for 2 days and on the 4th day it won't go in 3rd gear...
Starts fine, goes 1st to second fine and then when it's time to go third it just goes like in neutral.
Fluid looks good and don't smell burned, don't see anything wrong with valve body and no muddy stuff in the pan.
Tried unplugging main connector and drive it to see if it starts on 1st or 3rd, and it goes on 1st.
Did not find any electrical issues...
Can it be the OD clutches that are worn out?
Thanks for info.
Christ
Feb 17, 2023 at 11:30 AM
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JACOBANDNICKOLAS
  • AUTOMOTIVE REPAIR CONTRIBUTOR
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Hi,

Chances are it is a shift solenoid. However, there are several possibilities, and I need to know where to start.

Have you checked to see if there are diagnostic trouble codes? If you haven't, that is the starting point. What really needs to be done is a can-scan.

CAN stands for controller area network. Basically, the different modules are all tied together via a few wires. This type of scan will retrieve codes regardless of the module storing them.

Here is a link explaining how it's done:

https://www.2carpros.com/articles/can-scan-controller-area-network-easy

Let me know if you can have this done or if you already have done it. If you have, let me know what codes were retrieved.

I will watch for your reply.

Take care,

Joe.
Feb 17, 2023 at 9:14 PM
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CHRISTIAN CHENARD
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Ho yes forgot the code.
My code reader said,p0733 .
Which is incorrect gear ratio,third gear.nothing else.
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Feb 18, 2023 at 7:07 AM
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JACOBANDNICKOLAS
  • AUTOMOTIVE REPAIR CONTRIBUTOR
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Hi,

Okay, that helps. I have the diagnostics related, but I need to explain something.
The transmission system uses two speed sensors, one to measure input RPM and one to measure output rpm. These inputs are essential for proper transmission operation. Therefore, the integrity of this data is verified through the checks at the start of the diagnostics.


I attached everything related to the P0733. Take a look through them and let me know if you are comfortable performing the tests. If you need additional information, let me know.

Take care,

Joe

See pics below.
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Feb 18, 2023 at 5:55 PM
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CHRISTIAN CHENARD
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I Looked through pics and i don't have the scan (code reader) powerful enough, the numbers, and the knowledge to perform any of these test and teardown...maybe i can check input and output speed sensor, but i don't have the numbers i need to compare with and need pics that show which wire is what and procedures.
Feb 18, 2023 at 6:37 PM
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CHRISTIAN CHENARD
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I checked the input and output seep sensors, input tested 0.47 oms, power at 4.25v and ground continuity at 0.22oms...output tested at 0.46-47oms,power at 2.4v and ground continuity at 0.00 oms....could not do the magnet test because i couldn't take the sensors off w/o breaking the bolts.
Feb 19, 2023 at 10:24 AM