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I have a new 2010 DC, 5.7L 4x4 Rock Warrior. Does anyone else experience an annoying downshifting? It seems the tranny downshifts too soon thus raising engine rpms. Some have said this is normal due to emissions. Any thoughts?:confused:
 

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yes, the transmission is supposed to be smart.

It does some things that can be very annoying. When it drops down to first gear in a neighborhood because you are going slow and make a turn it surprises you and is uncomfortable. It will hunt between 1st and second in my neighborhood (lots of short distances between turns/stops). I am not sure if the transmission learns your driving habits but it makes sense because I drive like a bat out of hell until i get in my neighborhood then i drive like a granny and the transmission pisses me off every time.

It will also downshift on a hill if you tap the brake so it will engine brake down the hill.

-Tim
 

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I could tap the break on my '07 and engage the downhill assist but on my '10 I can't make it "turn on" the downhill assist. The dealer said it is not adjustable and the computer is what controls it. I want it to act like my '07 did and engage when I tap the break. the '07 would hold gear/speed going down hill and the '10 I have to ride the break going down hill cause it keeps accelarating. Any suggestions?
 

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I could tap the break on my '07 and engage the downhill assist but on my '10 I can't make it "turn on" the downhill assist. The dealer said it is not adjustable and the computer is what controls it. I want it to act like my '07 did and engage when I tap the break. the '07 would hold gear/speed going down hill and the '10 I have to ride the break going down hill cause it keeps accelarating. Any suggestions?
That is weird. I actually like the downhill assist feature...probably the only "smart" feature about the transmission that I like. Does your '10 have the 5.7 with the 6 speed trans?

-Tim
 

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RPM's Are Good ! but where in Arkansas are you from?
 

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That is weird. I actually like the downhill assist feature...probably the only "smart" feature about the transmission that I like. Does your '10 have the 5.7 with the 6 speed trans?

-Tim
Yes, I like the downhill assist feature too. My '07 functioned like I like it but my '10 does not. I have to ride the break going down hill in my '10. Yes, i had/have the 5.7 6 speed in the '07/'10.
 

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Yes, I like the downhill assist feature too. My '07 functioned like I like it but my '10 does not. I have to ride the break going down hill in my '10. Yes, i had/have the 5.7 6 speed in the '07/'10.
Well, if they both have the same engine/tranny then I do not have a guess. I haven't even looked in the owners manual of my '08 to see if it mentions those features built into the trans.

-Tim
 

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I was told by the dealership, to disconnect the batt for at least 20 minutes and id let the BCM relearn your driving habits. I have had both a 2007 CM Limited....and now a 2010 Tundra Grade Sr5...they both work the same....great truck. I worked for chevy and drove a Tundra...sure took a lot of crap about it..LOL
 

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Not sure but try putting it in S mode and see how that works for ya? Just a thought.
Yes, the S-mode will stop it from downshifting.

The wife's Corolla does it too. I personally like the downhill brake assist - it really helps keep the brakes cool on some of those longer downgrades in the mountains. The Tundra's downhill assist is sometimes a little too aggressive, but I'm thinking they made it that way to help with towing, not to mention the lower transmission gearing makes it much more noticeable.
 

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That's great to know THUMBSTER!!!!! I personally use S mode every day. I like the option of being able to control my descent when I want. Thanks for the confirmation; I wasn't really sure that was the ticket.
 

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I could tap the break on my '07 and engage the downhill assist but on my '10 I can't make it "turn on" the downhill assist. The dealer said it is not adjustable and the computer is what controls it. I want it to act like my '07 did and engage when I tap the break. the '07 would hold gear/speed going down hill and the '10 I have to ride the break going down hill cause it keeps accelarating. Any suggestions?
Here's something interesting I found in the 2010 owner's manual.

On page 177 of the owner's manual:
Use engine braking (downshift) to maintain a safe speed when driving down a steep hill.
On page 187 of the ownner's manual:
[FONT=Arial,Arial][FONT=Arial,Arial]Shift position uses
[/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]*[/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]1[/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]:To improve fuel consumption and reduce noises, set the shift lever in D for normal driving.
[/FONT]
[/FONT][FONT=Arial,Arial][FONT=Arial,Arial]*[/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]2[/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]:Selecting shift ranges S mode restricts the upper limit of the possible gear ranges, control

engine braking forces, and prevents unnecessary upshifting.

Additionally, when driving in S mode with Cruise Control being used, keep the following in mind:
 ​
 
 
 
n[FONT=Arial,Arial][FONT=Arial,Arial]When driving with the cruise control system (if equipped)
[/FONT][/FONT][FONT=Arial,Arial][FONT=Arial,Arial]The engine brake will not operate in the S mode, even when downshifting to 5 or 4 (6-speed models) or 4 or 3 (5-speed models). (→P. 221)[/FONT][/FONT]

So this leads me to believe that engine braking works in S mode.
[/FONT]
[/FONT]
 

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I could tap the break on my '07 and engage the downhill assist but on my '10 I can't make it "turn on" the downhill assist. The dealer said it is not adjustable and the computer is what controls it. I want it to act like my '07 did and engage when I tap the break. the '07 would hold gear/speed going down hill and the '10 I have to ride the break going down hill cause it keeps accelarating. Any suggestions?
Truly disappointing if the downhill grade logic from the 07-09 is missing from the 10. Please let us know if disconnecting the battery helps.
 

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[FONT=Arial,Arial][FONT=Arial,Arial]
So this leads me to believe that engine braking works in S mode.
[/FONT]
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works great in my '07 - I just put in about 2000 miles in the Sierra Nevada, anything from interstate 80 to Kaiser Pass, which is a narrow single lane killer of a pass, with 20% grades and all sorts of challenges. In S, the truck will hold any gear - I had to run a lot in first and second on the steep sections, and it will not upshift even from those low gears as long as you keep it in S and pick a proper top gear. There is a smart limit in the transmission that if rpm's get too high, it will protect the engine, I assume, but I never let it get anywhere near those revs. I never enabled the downhill assist, because I think it's only meant for low-gear offroad stuff, but I have to confess that I never looked at the manual close enough to know that for sure.

I find it also uses engine braking in D mode while city driving, especially when I am approaching certain stop lights on downhill roads. Thing is, on the next stop light approach on level ground, it won't do it. Not that smart, but hten I am new to automatics and don't have that many miles in with this truck to really know how it should behave. Most of the time it works well, but I've also had the surprise first gear drop in when I wanted to stay in second, but not too often.
 

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I like the feature. Works when going down a grade and even when I'm approaching red and I get off the gas and tap the brakes. If I actually come to a stop that's x-amount less stress on my brakes. If I change my mind and hit it again I'm already in the lower gear I need. Took some getting used to. Initially I didn't know it worked that way and was caught off guard when the engine braking kicked in and the truck started to seemingly slow on its own. Now that I'm used to it I'm happier with this than on old trucks with less sophisticated logic where it was all braking force to slow me down without a manual downshift.

That shift is gonna come either way. I'd rather have it happen while Im slowing down before I even need that lower gear again than have to hit the gas again and wait a second for it to happen.
 

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Use s mode, mine seems to hold a gear longer in S mode without downshifting which helps some on MPG on hilly highways,, around here I hit 5th gear alot on the 4 lane highways, alot more in D though
 

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Folks: Adding this thread....

I bought a 2012 used Tundra crewmax 5.7 (~25,000 kms) a couple months ago and I find the transmission downshifting/engine braking annoying as well. I have been thinking that there is something wrong with it but I am not sure. For the first few miles, it behaves as I would expect....ie....when you let go the accelerator it "free wheels". However, after the transmission gets "warmed up", once you take your foot off the accelerator its very likely to "engine brake/downshift". Sometimes I find it hard to tell if it has downshifted or if its just holding a lower gear longer than I think it should. And this is on level ground....not on a decline after a brake tap....

Does anyone have any ideas? Is this normal? Is there anything in the drivetrain or transmission that could otherwise cause this behaviour? Transmission fluid low etc??? Something in tranfer case...etc. etc...

I had the ECU reset but this didnt seem to make any difference. I only have a few days of bumper to bumper warranty remaining so if there is something wrong I would like to get it addressed.

Thanks for any feedback/advice.
 
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