I have a 2006 Dodge Ram 1500 here with a 5.7l which has a weird problem.
I must mention, I have diagnose fault code with wiTech MicroPod 2 scanner and this has NO DTC.
Transmission jerking / vibration while cruising
The TCC (torque converter clutch) never fully engage. If I understood correctly, it has 4 possible positions :
I’ve measured them with the oscilloscope
OFF : always off
PARTIAL : duty cycle around 50% with a slow frequency around 50 Hz
TRANSITION : duty cycle around 50% with a high frequency over 1 KHz
FULL ON : unable to check it…. it never goes into the Full ON mode
The OFF, PARTIAL and TRANSITION sequences are all OK but the PCM (or TCM) never request the FULL ON position and I think that’s the issue
While cruising on the highway and if the TCC is in the TRANSITION phase everything is OK and there’s no jerking.
When the cylinder deactivation or “Multi Displacement System” (MDS) engage (or when the V8 becomes a V4) … the TCC goes into the PARTIAL phase and after 1second of PARTIAL phase, the transmission begins to jerk. It feels almost like a misfire.
And thinking about it, it make sense. The TCC goes on and off 50 times per seconds so it’s normal that it creates a vibration.
I jumped the TCC to full ON manually by jumping the control wire to the ground and the jerking / vibration goes away.
So my question is …. what are the conditions for the TCM to control the TCC to FULL ON ?
I’ve searched google and I haven’t found the info i’m looking for.
I’ve looked at scan data and here are the mains one :
-TCC request & actual TCC status are always identical
-TCC request never goes to FULL ON or ON
-engine RPM and turbine speed have around +/- 50 rpm difference
-transmission oil T° is around 105 F
-TPS has normal range
-When Cylinder 1,4,6,7 disengage for MDS system, the TCC goes into PARTIAL state and stay in PARTIAL for a long time and that’s when the vibration begins
-the TCC sometimes goes into PARTIAL state for limited time with all 8 cylinders in function and there’s no vibration
-The TCC never enter FULL ON under no circonstances
once again, there’s no DTC, only customer compliant.
any idea what to look for ?
why the TCM never ask for FULL ON on the TCC ?
what are the conditions that needs to be met to go in FULL ON state ?
I do not want to replace the ECU.
The driver ( transistor) is OK since all the other States are working.
I also flashed the software in case it was corrupted and no changes.
I hate changing ECU without proofs.
I don’t have the truck with me but over 150 000km.
The transmission have been replaced 6 months ago with a used one with unknown km. All was going smooth until last Friday.
This truck had a supercharger installed a few years ago.
It was removed last year when the transmission died.
Like I mentioned, the jerking is only present when the tcc is in the PARTiAL state.
Plugs have been replaced last year. This isn’t coming from the engine.
So they replaced the whole transmission (it was on warranty) and the problem’s fixed…
I’m pretty confident in my 1st call : L/R solenoid sticking/gripping in the valve body.