tc lock
FOREIGN GURU
Joined: Jul 2006
Posts: 7,655
Likes: 7
From: Celaya, Gto. MX
More Turbo
Joined: Mar 2007
Posts: 708
Likes: 0
I have often thought about doing this mod. I hate the fact that my truck feels like it shifts again when the TC locks up, but my problem is I dont know much about when exactly I need to have it locked. I assum that it needs to be in higher RPMS, it seems like this might cause a lot of heat for the old tranny. What have you guys to say about this. I would like to solve my problem with a simple wire and switch but I wonder if I would cause more problems than fix.
For those of you with this mod when do you lock you TC? Thanks
For those of you with this mod when do you lock you TC? Thanks
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Lead Driver
Joined: May 2007
Posts: 8,606
Likes: 13
From: Belair md
i would say manually lock it after the 2nd gear shift is complete and rpms rasie a little to get your speed up. treat it like another gear
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Fleet Mechanic
Joined: Aug 2007
Posts: 1,508
Likes: 2
From: The boonies by Dallas OR
Originally Posted by 2 stroke man
why not on take off?
You can get a similar effect by flooring it from a start. If the throttle is above 3/4 in 1st or 2nd, the PCM locks the T/C above 2000 RPM.
You'll note an RPM drop when the T/C locks up in 1st at about 2000 RPM. If the learning strategy hits it just right, you'll notice no RPM increase when the T/C unlocks to shift into 2nd because the tranny shifts exactly as the T/C starts to slip. When the tranny drops to 2nd the RPMs drop, followed by a T/C lockup that makes the revs drop even more. The same sequence is involved in the 2nd to drive shift. This is always what happens in a drive to OD shift. If the timing is off, you may notice an increase in RPM because the T/C is slipping a little before the shift, or you may notice a period after the shift before the T/C locks back up.
Lead Driver
Joined: May 2007
Posts: 8,606
Likes: 13
From: Belair md
the tc shouldnt be locking at all in 1st gear, the converter wont lock till about 35 mph on light loads. if the converter were to be locked at any time in 1st gear the trans would get hot and you would give premature wear on the clutch
Lead Driver
Joined: May 2007
Posts: 8,606
Likes: 13
From: Belair md
i mean normal drivng in 1st gear, if it were to lock you wouldnt have enough fluid pressure to sustain the clutch and it would shudder or slip.
besides if you manually lock it too early you would defeat the purpose of having the converter in the first place, you would ovverride the stalling principles of the converter
besides if you manually lock it too early you would defeat the purpose of having the converter in the first place, you would ovverride the stalling principles of the converter
Post Fiend
Joined: Apr 2004
Posts: 12,835
Likes: 3
From: Silver Lake Dunes, MI
When I use my switch which is very rarely, I lock it after the 2nd gear shift after the RPM's get up so as not to lug then engine too much. I use it more for decel coasting than anything.