4R100 Auto
Senior User
Joined: Nov 2000
Posts: 240
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From: Sevierville USA
4R100 Auto
I have the above tranny in my 99 SuperDuty (see signature). I have noticed that sometimes it feels as though it has 2 second gears. It shifts into second and then it feels as though it does it again. Has anyone else noticed this? Is it common? or am I looking at replacing the tranny in the future? Thanks in advance for your input.
Sit. Stay.
Joined: Oct 2001
Posts: 18,308
Likes: 20
From: Washington State
4R100 Auto
[updated:LAST EDITED ON 10-Feb-02 AT 10:00 PM (EST)]Scott, check again. I'm sure you must be feeling the torque converter locking up. You should feel 1-2 shift, 2-3 shift, 3-3.5 (as some have described it) shift, 3-OD shift. That 1/2 shift is actually the torque converter locking up.
A simplistic answer is that the engine also spins a pump inside the tranny that pumps the fluid around, so it (the engine) turns a little faster to run it. Once the torque converter locks up, the engine will put 100% of it's energy through the tranny because it doesn't need to run that little pump. The locked-up TC is kinda like a clutch, so to speak.
You feel it by the RPM's dropping, similar to a shift in gears.
Ya dig?
A simplistic answer is that the engine also spins a pump inside the tranny that pumps the fluid around, so it (the engine) turns a little faster to run it. Once the torque converter locks up, the engine will put 100% of it's energy through the tranny because it doesn't need to run that little pump. The locked-up TC is kinda like a clutch, so to speak.
You feel it by the RPM's dropping, similar to a shift in gears.
Ya dig?
Senior User
Joined: Nov 2000
Posts: 240
Likes: 0
From: Sevierville USA
4R100 Auto
It feels like the revs build up a little then drop just a tad and picks back up. Is this what it feels like when the converter locks up? I don't know anything about automatics so bear with me.
Senior User
Joined: Nov 2000
Posts: 240
Likes: 0
From: Sevierville USA
4R100 Auto
You shouldn't be editing while I am replying 
Okay, that makes since and sounds exactly what I am talking about. I'll have to say that I don't like it though. Is there a way to make the converter lock up sooner like as soon as it hits 2nd gear?
Okay, that makes since and sounds exactly what I am talking about. I'll have to say that I don't like it though. Is there a way to make the converter lock up sooner like as soon as it hits 2nd gear? 
