Transmission function question
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Elder User
Joined: Mar 2002
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From: Huntsville, Alabama
Transmission function question
How do I know if the torque converter is in lock-up? When should it go into lock-up and when should it go out?
Will it go in in third or only in fourth?
Sometimes my transmission makes a noise when shifting into fourth (OD) that sounds like a grunt (for lack of duplicating the sound). It is brief and only when under higher load demands. Is this a sign of something going bad?
Will it go in in third or only in fourth?
Sometimes my transmission makes a noise when shifting into fourth (OD) that sounds like a grunt (for lack of duplicating the sound). It is brief and only when under higher load demands. Is this a sign of something going bad?
Molon Labe
Joined: Dec 2006
Posts: 5,272
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From: Alaska
Under normal driving you should be able to feel it lock in 3rd gear. Some early PCM's would lock the TC just before it shifts into 4th gear.
Count your shifts, you should feel 4 shifts, the 3rd will be your TC locking.
Count your shifts, you should feel 4 shifts, the 3rd will be your TC locking.
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Elder User
Joined: Mar 2002
Posts: 549
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From: Huntsville, Alabama
OK. Thanks. That is what I feel most of the time. If I am driving aggressively it seems to go into lock-up at the time of the 4th gear up-shift which is when I hear the noise.
I was used to my Lightning and the way it shifted. I could place my foot lightly on the brake and see the converter come out of lockup. I cannot repeat this process with this truck (and for good reason).
Thanks again.
I was used to my Lightning and the way it shifted. I could place my foot lightly on the brake and see the converter come out of lockup. I cannot repeat this process with this truck (and for good reason).
Thanks again.
Post Fiend
Joined: Sep 2003
Posts: 6,096
Likes: 26
From: Mesa AZ
How do I know if the torque converter is in lock-up? When should it go into lock-up and when should it go out?
Will it go in in third or only in fourth?
Sometimes my transmission makes a noise when shifting into fourth (OD) that sounds like a grunt (for lack of duplicating the sound). It is brief and only when under higher load demands. Is this a sign of something going bad?
Will it go in in third or only in fourth?
Sometimes my transmission makes a noise when shifting into fourth (OD) that sounds like a grunt (for lack of duplicating the sound). It is brief and only when under higher load demands. Is this a sign of something going bad?
Can't comment on the sound you are hearing. That is a new one to me. Are you hearing any weird clattering noises when your truck is idling in Park?
Frmr Ford Trans Engr
Joined: Aug 1999
Posts: 24,725
Likes: 2,651
From: SE Florida
Franko72 answered the question. The torque converter lock feels like a small RPM shift. Sometimes it's hard to pick up. It can be seen in the tach, too. If you're accelerating and the engine RPM hold steady for about 2 seconds while the truck is still accelerating that is the torque converter locking.
Yes it can. In first and second the converter can lock if engine RPM is high enough AND the go pedal is at least 3/4 of the way to the floor. I don't remember the RPM number.
The noise on lockup is probably the start of torque converter shudder. That is usually an indication that the ATF needs to be changed.
The noise on lockup is probably the start of torque converter shudder. That is usually an indication that the ATF needs to be changed.
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