Ok, I am new to the forum and trying to figure out a few trans issues. Everything I read talks about torque convertor lock up. What exactly is this and what is the purpose? Thanks.
What is torque convertor lock up?
natesimpson74
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Ok, I am new to the forum and trying to figure out a few trans issues. Everything I read talks about torque convertor lock up. What exactly is this and what is the purpose? Thanks.
While I don't know the exact specifics on how it works, I can enlighten you some.
The torque converter has a clutch of sorts inside that the computer can lock when it deems neccesary. The torque converter clutch (TCC) is applied in overdrive and sometimes other gears to lower engine RPM, reduce parasitic losses as well as reduce heat generation. This leads to higher mileage, reduced noise and longer life.
The torque converter is the main generator of heat in an automatic transmission, the more load you apply to it, the more heat it makes. Locking the TCC, as I mentioned above, reduces this heat generation.
The torque converter has a clutch of sorts inside that the computer can lock when it deems neccesary. The torque converter clutch (TCC) is applied in overdrive and sometimes other gears to lower engine RPM, reduce parasitic losses as well as reduce heat generation. This leads to higher mileage, reduced noise and longer life.
The torque converter is the main generator of heat in an automatic transmission, the more load you apply to it, the more heat it makes. Locking the TCC, as I mentioned above, reduces this heat generation.
This quote sums up the answer to this thread. If you have more questions about it, then it's best you consult your Service Manual.
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Thank you. That's kind of what I was thinking, but I wasn't sure.
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Also just to add a little to it.. you only get converter lock in 3rd and 4th gear.. If you watch your tach you will see it drop a little in 3rd when it locks, in 4th gear you see it drop a good deal when it locks... You will not get converter lock till the tranny reaches a certain temp. and if the tranny gets to hot it will disengage as well.
I'm not positive about your 44RE, but the 46RH in my dad's truck doesn't lock the TC in 3rd unless you turn off the OD. The same is true for my 5-45RFE.
Disengaging the the TC lockup when the trans gets hot would make no sense as it would make MORE heat, like I said above.
Disengaging the the TC lockup when the trans gets hot would make no sense as it would make MORE heat, like I said above.
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I was talking about the RE, thanks for clearing that up
The 46RE will not lock the converter in 3rd gear with OD on. Only with OD off. If it locked it in third with the OD on, then it would have to unlock to shift into OD which could cause some issues with synchronization and lots of people complaining about slow shifts.
There's really no need for it to unlock to perform a shift, only to smooth the shift out. My trans will shift into 4th, lock the TC then shift to 5th without unlocking the TC. That's the normal shift schedule.
If I get the timing and throttle input right, I can get it to go from 3rd locked TC into 4th without unlocking as well...but I'm just tricking it, more or less.
If I get the timing and throttle input right, I can get it to go from 3rd locked TC into 4th without unlocking as well...but I'm just tricking it, more or less.
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I just want to let you guys know you are awesome. Even though there are disagreements the right answer usually comes out. I was really wondering why the rpm's dropped after it shifted into 3rd. I never really noticed it in my other cars until I hve had problems with the dak.
One more question, how do you know if the torque converter is working correctly or if it is junk?
One more question, how do you know if the torque converter is working correctly or if it is junk?
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The 44RE doesn't have OD, at least mine doesn't.
All transmissions these days have overdrive.
Yes it does. :huh:
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Well, I can't turn it on or off. No switch for me :huh:
Huh whaaa?
I'm not familiar with the pre-01 interior, but my switch is a momentary push button on the end of the shifter. Otherwise, my dad's 95 Ram has a switch on the dash. Still another option would be the shifter itself, you may have to drop it down to 3rd. I dunno...
I'm not familiar with the pre-01 interior, but my switch is a momentary push button on the end of the shifter. Otherwise, my dad's 95 Ram has a switch on the dash. Still another option would be the shifter itself, you may have to drop it down to 3rd. I dunno...
Description:
4 speed rear wheel drive automatic overdrive transmission. Unit identification:
* Hydraulic (RH) units utilize a 2 or 3 pin case connector.
* Electronic (RE) units utalize an 8-pin case connector.
Ratios:
1st: 2.740
2nd: 1.540
3rd: 1.000
4th: 0.690 Hydraulic (RH) 1988 - 1996.
Electronic (RE) 1993-ON
4 speed rear wheel drive automatic overdrive transmission. Unit identification:
* Hydraulic (RH) units utilize a 2 or 3 pin case connector.
* Electronic (RE) units utalize an 8-pin case connector.
Ratios:
1st: 2.740
2nd: 1.540
3rd: 1.000
4th: 0.690 Hydraulic (RH) 1988 - 1996.
Electronic (RE) 1993-ON
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pumping losses within the torque converter reduce efficiency and generate waste heat. In modern automotive applications, this problem is commonly avoided by use of a lock-up clutch that physically links the pump and turbine, effectively changing the converter into a purely mechanical coupling. The result is no slippage, and virtually no power loss.
Do you have a link to that article? I'm curious to read the rest of it.
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