When does a stock auto transmission lock and unlock the torque convertor?
01-03-2008, 10:19 AM
#16
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45 mph in 4th is normal lock up speed for light to moderate acceleration without being in tow haul. It could be a little higher speed depending on gear ratio. In tow haul the T/C on an 06 will lock immediatly after the 2-3 upshift in 3rd, then unlock shift to 4th and relock.
If you are at WOT and not in t/h mode the trans will still lock the 3rd gear upshift. As far as deceleration goes the 48re will stay locked regardless if you are on the brakes or not, down to 45mph then unlock. In tow haul it will stay locked in 4th then downshift to 3rd and relock for engine braking.
It is a very different stategy from the 4R100 you had in your excursion.
Ford likes to unlock them as soon as it see's a brake light signal, Dodge does'nt.
If you are at WOT and not in t/h mode the trans will still lock the 3rd gear upshift. As far as deceleration goes the 48re will stay locked regardless if you are on the brakes or not, down to 45mph then unlock. In tow haul it will stay locked in 4th then downshift to 3rd and relock for engine braking.
It is a very different stategy from the 4R100 you had in your excursion.
Ford likes to unlock them as soon as it see's a brake light signal, Dodge does'nt.
01-03-2008, 10:36 AM
#17
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Torque converter
How do you know? Its a 'feeling'. You feel it lock if its pulling a slight hill, the rpm drops a little, and if your accelerating, you feel it take hold, no slip.
I know thats abstract, but it does have a feeling. kinda hard to describe. Its easy to show, my wife even notices when it does. Mine locks right at 39-40 if up to operating temp, and not a heavy acceleration. I have have had it stay engaged as low as 36mph, if you let him pull a little and slow some going up a slight hill and keep a steady 'light' foot on the accelerator.
My jeep wrangler will do the same with his automatic trans. You just have to pay attention and not hammer it.
I do notice if you put my 05 in two/haul mode and you let off the accelerator, the TC stays locked, like when drifting downhill. I guess for something like a dynamic braking effect where the trans tries to slow you with some drag.
But if the truck is out of tow/haul, TC unlocks while going downhill and you free wheel. My 96 Dodge (gas) would do the same. It had a 46RE trans and operated about the same way. But this 48RE shifts much crisper. I like it.
Just watch him, you'll notice/feel it when it locks and unlocks. Its good.
I know thats abstract, but it does have a feeling. kinda hard to describe. Its easy to show, my wife even notices when it does. Mine locks right at 39-40 if up to operating temp, and not a heavy acceleration. I have have had it stay engaged as low as 36mph, if you let him pull a little and slow some going up a slight hill and keep a steady 'light' foot on the accelerator.
My jeep wrangler will do the same with his automatic trans. You just have to pay attention and not hammer it.
I do notice if you put my 05 in two/haul mode and you let off the accelerator, the TC stays locked, like when drifting downhill. I guess for something like a dynamic braking effect where the trans tries to slow you with some drag.
But if the truck is out of tow/haul, TC unlocks while going downhill and you free wheel. My 96 Dodge (gas) would do the same. It had a 46RE trans and operated about the same way. But this 48RE shifts much crisper. I like it.
Just watch him, you'll notice/feel it when it locks and unlocks. Its good.
01-03-2008, 11:16 AM
#18
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My 07 5.9 locks at 50 MPH in O/D only. With tow/haul or the exhaust brake engauged 3rd will lock at 30 MPH and O/D will lock at 48 MPH.
The easiest way to tell if your converter is locked is to step on the go pedal, if the RPM's jump up quick then it's unlocked.
The easiest way to tell if your converter is locked is to step on the go pedal, if the RPM's jump up quick then it's unlocked.
01-03-2008, 11:29 AM
#19
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Mine locks as soon as I gas on it .... and FLIP the t/c lock switch 
if you have an aftermarket T/C you would LOVE a lock switch...BUT you NEED an aftermarket T/C and input shaft OR ...
YOU ARE GOING TO BREAK SOMETHING !!
Believe me
if you have an aftermarket T/C you would LOVE a lock switch...BUT you NEED an aftermarket T/C and input shaft OR ...
YOU ARE GOING TO BREAK SOMETHING !!
Believe me
Last edited by belgianmagic; 01-03-2008 at 11:30 AM. Reason: Spelling
01-04-2008, 07:35 AM
#21
Administrator ........ DTR's puttin fires out and workin on big trucks admin
How do you know? Its a 'feeling'. You feel it lock if its pulling a slight hill, the rpm drops a little, and if your accelerating, you feel it take hold, no slip.
I know thats abstract, but it does have a feeling. kinda hard to describe. Its easy to show, my wife even notices when it does. Mine locks right at 39-40 if up to operating temp, and not a heavy acceleration. I have have had it stay engaged as low as 36mph, if you let him pull a little and slow some going up a slight hill and keep a steady 'light' foot on the accelerator.
My jeep wrangler will do the same with his automatic trans. You just have to pay attention and not hammer it.
I do notice if you put my 05 in two/haul mode and you let off the accelerator, the TC stays locked, like when drifting downhill. I guess for something like a dynamic braking effect where the trans tries to slow you with some drag.
But if the truck is out of tow/haul, TC unlocks while going downhill and you free wheel. My 96 Dodge (gas) would do the same. It had a 46RE trans and operated about the same way. But this 48RE shifts much crisper. I like it.
Just watch him, you'll notice/feel it when it locks and unlocks. Its good.
I know thats abstract, but it does have a feeling. kinda hard to describe. Its easy to show, my wife even notices when it does. Mine locks right at 39-40 if up to operating temp, and not a heavy acceleration. I have have had it stay engaged as low as 36mph, if you let him pull a little and slow some going up a slight hill and keep a steady 'light' foot on the accelerator.
My jeep wrangler will do the same with his automatic trans. You just have to pay attention and not hammer it.
I do notice if you put my 05 in two/haul mode and you let off the accelerator, the TC stays locked, like when drifting downhill. I guess for something like a dynamic braking effect where the trans tries to slow you with some drag.
But if the truck is out of tow/haul, TC unlocks while going downhill and you free wheel. My 96 Dodge (gas) would do the same. It had a 46RE trans and operated about the same way. But this 48RE shifts much crisper. I like it.
Just watch him, you'll notice/feel it when it locks and unlocks. Its good.
My t/q locks regardless of operating temp, it was -5 yesterday morning, truck plugged in all night, pull out the driveway and take it easy, make 45 mph and the t/q locks up.
Also when my t/q locks it engages like another shift,(firm and positive).
I have a hill that I go down everyday to get to work, it is immediately after a stop light, upon acceleration from the light and at the top of the hill, (long gradual coasting grade) I'm at 40mph, well I coast the entire length of the hill gradually gaining speed, but in the middle of the hill I would always feel a hiccup, (don't know what else to call it), then my speed would stabilize at 45-46 mph. After the 3rd or 4th time of this happening I started to really pay attention to it, turns out the t/q was locking up right at 45 while I was coasting freely.
Great info from everyone, funny how every truck has different operating characteristics even it they are the same year.
Tim
01-04-2008, 12:39 PM
#22
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Was -30C here yesterday morning and my TC locked up like it does every other day at any operating temp ... under light throttle at about 80 km/h. Also feels just like another shift ... actually the smoothest one of all ... firm and positive also. I believe the '06 also locks in 2nd & 3rd as well as 4th ... I remember the tech showing me this when we were driving with the star scan hooked up ... and reading this in the manual.
01-04-2008, 10:39 PM
#24
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I added a light to tell me when the TC is locked. Then I went ahead and added the mystery switch. You can wire the light two different ways or use two lights. One way tells you when the TC locks and the other tells you when you locked the tc with the mystery switch. If you are interested read the thread on the DIY mystery switch.
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