Transmission problems
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Transmission problems
Have a 2006 dakota, when I drive about 45 and keep it at that speed the tac will jump up and down from about 1500 to 1800 and it seems like the transmission is kind of going between gears. Is this a tork converter problem. Had new fluid and filter replaced. Thanks
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Joined: Jun 2011
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If it's the V6 / 42RLE trans with 3.55 rear-end gear ratio, I'd say it's acting the way it was programmed...I've noticed under light acceleration or steady speeds when warm (with TOW/HAUL not activated) that the transmission is programmed to act as such:
35~39mph 3rd gear
40~43mph Shifts to and holds 4th gear with torque converter clutch (TCC) full lockup (very low engine rpm ~1200-1300)
44~49mph Torque converter clutch unlocks or goes into "partial lockup" (constant slippage) while remaining in 4th gear, and maintains or fluctuates around the higher rpms you described (1500-1800).
50~above Torque converter clutch fully engages again and maintains lockup. In this condition, the rpm at 50mph settles to about 1600rpm.
I don't know why they programmed the TCC to act like that around 44~49mph, but it's a range of speeds I try to avoid because of it...Seems like that continuous slippage of the TCC would only aid in wearing it out.
From the 2005 service manual:
35~39mph 3rd gear
40~43mph Shifts to and holds 4th gear with torque converter clutch (TCC) full lockup (very low engine rpm ~1200-1300)
44~49mph Torque converter clutch unlocks or goes into "partial lockup" (constant slippage) while remaining in 4th gear, and maintains or fluctuates around the higher rpms you described (1500-1800).
50~above Torque converter clutch fully engages again and maintains lockup. In this condition, the rpm at 50mph settles to about 1600rpm.
I don't know why they programmed the TCC to act like that around 44~49mph, but it's a range of speeds I try to avoid because of it...Seems like that continuous slippage of the TCC would only aid in wearing it out.
From the 2005 service manual:
TORQUE CONVERTER CLUTCH (TCC)
In a standard torque converter, the impeller and turbine are rotating at about the same speed and the stator is freewheeling, providing no torque multiplication. By applying the turbine’s piston and friction material to the front cover, a total converter engagement can be obtained. The result of this engagement is a direct 1:1 mechanical link between the engine and the transmission.
The clutch can be engaged in second, third, and fourth gear ranges depending on overdrive control switch position.
If the overdrive control switch is in the normal ON position, the clutch will engage after the shift to fourth gear. If the control switch is in the OFF position, the clutch will engage after the shift to third gear.
The TCM controls the torque converter by way of internal logic software. The programming of the software provides the TCM with control over the L/R-CC Solenoid. There are four output logic states that can be applied as follows:
² No EMCC
² Partial EMCC
² Full EMCC
² Gradual-to-no EMCC
NO EMCC
Under No EMCC conditions, the L/R Solenoid is OFF. There are several conditions that can result in NO EMCC operations. No EMCC can be initiated due to a fault in the transmission or because the TCM does not see the need for EMCC under current driving conditions.
PARTIAL EMCC
Partial EMCC operation modulates the L/R Solenoid (duty cycle) to obtain partial torque converter clutch application. Partial EMCC operation is maintained until Full EMCC is called for and actuated. During Partial EMCC some slip does occur. Partial EMCC will usually occur at low speeds, low load and light throttle situations.
FULL EMCC
During Full EMCC operation, the TCM increases the L/R Solenoid duty cycle to full ON after Partial EMCC control brings the engine speed within the desired slip range of transmission input speed relative to engine rpm.
GRADUAL-TO-NO EMCC
This operation is to soften the change from Full or Partial EMCC to No EMCC. This is done at mid-throttle by decreasing the L/R Solenoid duty cycle.
In a standard torque converter, the impeller and turbine are rotating at about the same speed and the stator is freewheeling, providing no torque multiplication. By applying the turbine’s piston and friction material to the front cover, a total converter engagement can be obtained. The result of this engagement is a direct 1:1 mechanical link between the engine and the transmission.
The clutch can be engaged in second, third, and fourth gear ranges depending on overdrive control switch position.
If the overdrive control switch is in the normal ON position, the clutch will engage after the shift to fourth gear. If the control switch is in the OFF position, the clutch will engage after the shift to third gear.
The TCM controls the torque converter by way of internal logic software. The programming of the software provides the TCM with control over the L/R-CC Solenoid. There are four output logic states that can be applied as follows:
² No EMCC
² Partial EMCC
² Full EMCC
² Gradual-to-no EMCC
NO EMCC
Under No EMCC conditions, the L/R Solenoid is OFF. There are several conditions that can result in NO EMCC operations. No EMCC can be initiated due to a fault in the transmission or because the TCM does not see the need for EMCC under current driving conditions.
PARTIAL EMCC
Partial EMCC operation modulates the L/R Solenoid (duty cycle) to obtain partial torque converter clutch application. Partial EMCC operation is maintained until Full EMCC is called for and actuated. During Partial EMCC some slip does occur. Partial EMCC will usually occur at low speeds, low load and light throttle situations.
FULL EMCC
During Full EMCC operation, the TCM increases the L/R Solenoid duty cycle to full ON after Partial EMCC control brings the engine speed within the desired slip range of transmission input speed relative to engine rpm.
GRADUAL-TO-NO EMCC
This operation is to soften the change from Full or Partial EMCC to No EMCC. This is done at mid-throttle by decreasing the L/R Solenoid duty cycle.
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Joined: Apr 2018
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Just wanted to say thanks for the info in this thread (especially the very detailed post by erau). I have an '05 and the tranny does pretty much exactly what is described. The 44-49 mph range was concerning me slightly as it kinda feels like it is searching for the right gear to be in lol. Somewhat weird feeling, but not like "oh f***" sort of weird. The truck has done it since I bought it and only has 125k miles on it. I've only had the truck about 1.5 years, so nice to know this is likely normal.