For a sudden total failure of 3rd gear in a 545RFE, I would drop the pan and look at the passenger side of the valve body (the accumulator cover). Odds are you have a blown cover. Mopar sells a repair kit (new cover, with one new piston and new screws). You don't have to replace the entire valve body. If you're lucky (and the OD clutch hasn't been too badly damaged), replacing a blown cover plate will fix it.Hi there. I'm a noob when it comes to this stuff so I thought I'd mention that first. I have exactly the same problem as jordantractor except I have a 2014 ram 1500 slot 2wd 5.7 hemi. I was hoping for some guidance before I remove the pan.i have not done the check yet of disconnecting trans harness and driving to see if it goes directly into 3rd. I have auto transmission with the manual button on the shift arm. Any help would be appreciated, it happened suddenly, no warning, and I get only code 0733. I do not get code 0750 which would indicate a bad solenoid pack, is this right? Again, any help would be greatly appreciated
Yes, the OD accumulator piston has only one spring. The others have two nested springs.Hey transengineer. You were correct about the cover plate. It was bent, I removed the valve housing and ordered the kit. Couple of questions. Does the od piston only have the single spring, the 4 others have double springs....As well, how would I know if the od clutch has been damaged? Thanks again for the help and support. I really appreciate it, learning about these things and saving the money.
Since you have no line pressure faults, I don't think low LP is your problem, but you (or your shop) can check it by getting a special tool (tee fitting) that allows you to plumb a mechanical pressure gauge into the line pressure circuit, while the LP sensor is still connected. That way you can verify that the sensor reading is accurate.Hi folks
here are the updates...
Ive re-built the tranny. The OD clutches were gone obviously. Found some more mistakes, that were done from previous re-builts by shop mechanics...so far I promised myself that will take days off and do all the work myself..
Ok, put the tranny back into the car. Fluid level ok. New filters etc. Started, shifted to D. Had delays. It engaged after about 5 seconds or so. This did not make me happy obviously.
So took it for drive, very gentle on throttle. up to 70kmh, 3rd gear shifted ok. After that, bang....again p0733..again same problems.
Came back to yard. Disconnected main harness to solenoid valves...feels like in 1st...
Can I burn OD clutches with very gently drive, in total about 5-6miles??
When I disconnected the harness, thus cut the power to main regulator valve, which regulates main pressure in valve body, the shift to D was instantaneous. Like it should. In other words, the engagement was instant. For some reason I thing the TCM does not regulate the pressure inside the transmission properly. This could explain why I slip clutches, as it does not have enough pressure to hold em together.
I think the problem is not the tranny any more. As I will keep re-building it and it will burn itself.
Any other suggestions?
The TCM should adjust the line pressure until the LP sensor reading matches the Desired LP. And if it can't properly adjust the LP, then it should set a line pressure fault. So that tells me that your TCM "thinks" the line pressure is OK, which means most likely you have a bad LP sensor (that is reading like 120 psi when the actual LP is only 50-60 psi).I made a special tool for reading line pressure...and guess what..
I have only 50-60 psi when running. In D, Reverse etc. No wonder I burned clutches in the past.
The odd thing, when I unplug the harness from either the solenoid block or from the line pressure sensor, boom. I have full 130-140 psi. SO this tells me that my pump is ok.
For some reason TCM keeps duty cycle (PWM signal) down to 10-20% to line pressure regulator, and it regulates the pressure down to 50 psi or so.
Will investigate reason for that
I think you may be making things too complicated. You need to compare the sensor reading to the mechanical gauge reading, to see if the sensor reading (or, more accurately, the TCM conversion of the sensor voltage) matches the gauge reading. That is step 1.Another thing I need to test on other vehicle , if I get a chance to get hold off is...
Line pressure sensor is 3 wire connector. 1. Ground. 2. 5v reference voltage . 3 . Signal output
When the sensor is DISCONNECTED, both of 2 and 3 have 5v reference. When the sensor is CONNECTED, line pressure drops to 2.4v something. So basically the sensor shorts the 5v reference to ground based on sensors impediance. No wonder I have full pump pressure on tranny when the sensor is out.
I need someone with more in depth knowledge of the system than myself to have technical chat...