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Discussion Starter · #1 · (Edited)
I have about 3000 miles on my new Tundra Crewmax 4x4 5.7 and I simply love it overall.
But I've started to notice a few transmission & throttle oddities...

First, the throttle is very sensitive, as if 75% of the available throttle is confined to the first 25% of the pedal travel.
Is there a TPS calibration that can be done to get a more linear throttle?

Second (and it might be tied to the sensitive throttle) my engine will often rev out too (light-loaded) far before the transmission upshifts in the first couple of gears under moderate throttling... its not really accelerating much at that point and just wasting gas while it delays the upshift for a second or two around 3000rpm.
Its not extremely bad, just annoying.

Third, at highway speeds it lugs along nicely with the converter locked up, it will remaim locked up if I let off the throttle (good), but when I gently tip-in the trottle the converter unlocks, revs up a hair, then locks back up... whats the deal with that?
Is it normal to unlock and then relock opon throttling?
 

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My 2013 when cold seems to do the same thing as yours when shifting out of first at 3000 rpm. I just take it easy on the first few miles like Bad Dad's Tundra mentioned.
 

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Discussion Starter · #3 ·
Yea, your probably right about being cold (even though its been 90F).
I mostly notice it not far from the house.
Oddly, its slow going thru the first couple of gears but zips right on thru the upper gears.

Anyone else notice the converter unlocking/locking at highway speeds when applying throttle after coasting for a few seconds?
 

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My 2013 does the same thing. I think it does it warm as well. It revs out really high instead of shifting to the next gear. It really on,y does it if I punch it really fast. It is weird though. Seems like if it shifted it would go a lot quicker instead of reving to the moon.
 

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I bought my rig (2005 V-8 Automatic) used with 20K miles on it. The original owner of this vehicle had it in for the lazy shifting issue when it was brand new. I bought it and put 10K miles on it and it still does the same thing.
It's slow to shift into the next gear ~ especially when the vehicle has only been driven for a mile or so. At times it will do this even after it's fully warmed up and has been driven for 15 or more miles. Not as often now as when I first bought it but it will do it every now and then.
I thought the throttle was extremely sensitive when I first started driving this Tundra. I'd chirp the tires leaving every stop sign in town. Now that I've had it for awhile I suppose I've gotten used to it ~ it's not so much of an issue now.
And so it goes ~ Your concerns seem to be par for the course with these electronically controlled vehicles that we're driving.
 

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The convertor lock/unlock with throttle input is normal (it will also do this if you two foot and tap the brake pedal ever so slightly)

The trans delaying 1-2 shift is also normal, will do it more when cold. Wait till you swap air filter to a cai or the like. You will actually hear the throttle chop between first and second gears, sometimes second to third. Primarily when the vehicle is cold.
Remember, it may be 90° out, but the trans fluid is still not to temperature, nor is the rest of the vehicles components.
 

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Discussion Starter · #8 ·
Powertechn2 said:
The convertor lock/unlock with throttle input is normal .
Any clue as to why they programmed it thataway?
Seems to me it wastes fuel and may unnecessarily wear the converter.

I'd bet that fine tuning the throttle pedal, shift points and lockups could squeeze another mpg out of this truck as-is.
 

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My '13 is very touchy at tip in also. So much I creep away from stop lights and sign otherwise it seems like im nailing it. At less than 25% tip in of the throttle.

Just makes it more of a beast I guess, I do like the power delivery and smoooooooth tranny!!!
 

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Torque converter issue is normal and pretty standard for most every lockup converter vehicle I've driven. My old 96 explorer did it, my 99 accord did it, my 98 chevy k1500 did it. Lets the vehicle coast instead of feel herky jerky on the freeway.

My 13 tundra is in the same boat as far as shifting, but with the a/c on it feels clunky. It's becoming quite irksome, actually. Shifting to D from Park feels like u just got rear ended in a parking lot - RPM's drop to abt 500 as it slides in to gear then instantly jumps to 900 and jerks the whole car forward. 2-3 shift clunks pretty bad, too.
 

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Turning off traction control. I didn't know about it until last night. I just did a quick google search and learned how to do it. Works awesome.
 

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Yeah you will like it. While stopped press and hold traction control button for about 5 seconds. Two lights will pop up. Then hold it down for about 3 more seconds and one red light will disappear but two others will stay on. One of the will say traction control or vsc off. Then hammer it!
 

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Likely the convertor does the lock/unlock thing because it is a convertor, not a clutch. If it didn't the vehicle would ride harsh and jerky, lug down the engine when it shouldn't and overall driveability as well as longevity would likely suffer.

Then again, this sorta falls under the category "It just does" as far as to why the torque converter locks and unlocks...
 
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^^^ what PowerTechn2 said... IIRC, this transmission only locks up in 4, 5, and 6 gears. Unlocking the converter when you take your foot off the pedal reduces shock loading on both ends of the drivetrain and improves powertrain feel, drivability, and longevity. U joints, ring and pinions, and transmission input/output shafts don't like shock loads so the converter lessens the blow, so to speak, and mediates between the driving force (the engine) and the driven parts (the rest of the drivetrain.
 
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