2003 Quickly Shifts Through Third
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From: California Desert
2003 Quickly Shifts Through Third
2003 F250 V10. I've noticed that, especially under partial throttle, the truck will shift into third and then quickly, within 2 - 4 seconds, shift into 4th. Now, with a performance tune from 5-Star, the problem seems worse. The transmission almost feels like it's skipping 3rd altogether under partial throttle and only holding it for 1 - 2 seconds under heavy throttle. All other gears shift solidly. The transmission fluid looks clean and smells normal. Any ideas?
Logistics Pro
Joined: Nov 2004
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How is it not normal? May be just normal shifting.
In other words, did it used to hang in third? Is it shifting rough? Lugging?
maybe put it in tow/haul and find a long incline to go up nice and easy and see if you can get it to hang in third
In other words, did it used to hang in third? Is it shifting rough? Lugging?
maybe put it in tow/haul and find a long incline to go up nice and easy and see if you can get it to hang in third
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From: California Desert
Well, whenever it does decide to hold third, it shifts in and out just fine and it doesn't feel like there is any slip. It pulls about like the rest of the gears with no felt, heard, or seen RPM spike that would indicate slipping. On a drive last night, it seems to hold third a bit longer when the transmission temps are still cold (temp gauge has never gone about the half point since I've owned it). I guess the main reason it doesn't feel normal is that, when it does quickly shift through third, or bypasses it completely, it feels like it's lugging the engine in 4th while still trying to accelerate. I'm starting to wonder if one of the shift solenoids isn't opening (or closing) fully?
Lead Driver
Joined: Nov 2008
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From: South Jersey
It's not going into 4th (actually over drive) the trans is locking the tq converter up. The SCT is making you feel it worse because the tuner adjusts timing and pressure related to tq converter lockup
Fleet Mechanic
Joined: Jan 2016
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Just a thought. Have you counted the shifts? Is it possible that there are 6 shifts? The 5R110W is a 6 speed but one speed only is relevant at -5 degrees or so. If the trans temp sensor has gone bad it may be thinking it is cold and using 3rd (I could be wrong) when it normally wouldn't be engaged.
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Frmr Ford Trans Engr
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From: SE Florida
Just a thought. Have you counted the shifts? Is it possible that there are 6 shifts? The 5R110W is a 6 speed but one speed only is relevant at -5 degrees or so. If the trans temp sensor has gone bad it may be thinking it is cold and using 3rd (I could be wrong) when it normally wouldn't be engaged.
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Posting Guru
Joined: Nov 2003
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From: California Desert
After rewatching the video, I'm thinking maybe the converter is locking up almost as soon as it shifts into third, then it's holding lockup through the shift into fourth. Does that seem normal?
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Posting Guru
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From: California Desert
It seems you would want lockup at the end of acceleration, but I'm not the engineer. Thanks for confirming theres nothing wrong and I haven't been paying attention to my transmission over the last year.
Frmr Ford Trans Engr
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From: SE Florida
As you are accelerating and the converter is spinning faster it gets to what is called the coupling point. This is where there is no more torque multiplication, only slip. If you lock the converter here you get more torque to the wheels, which means more acceleration.
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From: California Desert
As you are accelerating and the converter is spinning faster it gets to what is called the coupling point. This is where there is no more torque multiplication, only slip. If you lock the converter here you get more torque to the wheels, which means more acceleration.
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