Tacoma Transmission, not a rant, a theory…

except they don't really leave the door open for tuning. they lock down the ECUs and they are very hard to crack.

 

For those that haven’t done it yet… get your truck tuned. Aside from the price, there is no downside.

I’ve been tuned since April of 21. Currently running a custom version of kdmax +xt. The truck shifts like a normal vehicle thru all gears, more TQ everywhere, better gas mileage. The lack of TQ is still noticeable in 5-6 gears running into a headwind, but overall the truck is soooo much better tuned.

 

tunes are only available for some trucks

 

Good point, but I believe tunes are available for most 3rd Gens. Check with a tuner to see if your truck can be tuned, for the most part they will know by the year of your truck and also want to know if any TSBs have been loaded.

My truck was so lousy that if I was stuck with the stock tune I’d have sold it.

 

Everyone thinks about it too much. Just drive the truck for 3 or 4 k miles
If you not happy get it tuned. The 3.5 is tuned in our trucks for mileage Nan’s emissions
As everything is now . It’s only going to get worse. You have cars now with 3 cylinder turbos.All the manufacturers are trying to make more powerful engines / smaller ( less emissions) and more power . Everyone is excited about a 4 cylinder twin turbo in the future Tacoma , and it will probably be powerful
But will it last ?? I guess we will see . Looking back in the past to Turbo Mustangs and BMW’s and other cars with tiny engines boosted to the max , they did not last .

 

I've been perfectly happy utilizing the various S transmission settings in the Sierras.

 

Don't know what to tell you. What I said is true. Tacomas don't have true manual shift mode capability. S is only a gear limiter. It will appear to work well if you're going downhill and going down in S mode gears as it will obviously go from 4-3-2 etc when you do that. Try accelerating hard and shifting the gear selector from S1-2-3-4 before redline, and you'll see nothing is happening and truck will simply shift its own gears.
Likewise if you leave it in S4, it will shift all over the place on its own, which is not what vast majority of "S" mode automatics do in virtually every other vehicle on the market.

This doesn't mean S mode sucks or anything, it's just different from what a lot of manual S modes out there do.

 

Im more concerned about the transmission/torque converter shudder some have. I thought it could be low transmission fluid but turned out not to be the case.

I did a drain and fill on mine a month ago and ever since I lost 1 mpg. Still trying to figure that one out.

 

You gotta learn to drive it more reasonably man, you’ll get a lot more out of S mode. Why would you push it to redline and shift up 4 gears all at once without giving it a chance to shift thru each gear anyway? If you let each gear wind up to where you’d naturally up shift as you would with a manual, It’ll do what you tell it to. It’ll hold a gear when you need it to hold, and it’ll shift when you tell it to shift.

 

I think its fairly simple what is going on.
A typical AT is programmed to attempt to stay in the engines ideal powerband. With most engine designs this works out fine. Ideal powerband ends up being near ideal gas mileage. Thats the whole point of CVTs, they can hug the ideal power band very well even if they are boring to drive and snap like a rubber band with high power engines.
With tacomas V6, the power is all at high RPMS. If the AT behaved like a typical AT, it would eat up ridiculous amounts of gas. So instead of preferring the power band it prefers near 1K rpms for efficiency and is extremely aggressive about shifting to keep rpms that low.
But the engine has very little torque there (being generous). Combine that with the intentionally slow throttle response (probably to smooth downshifting out) and it feels like it has no power and when the driver asks for power dances around the gears to try to get back to 1K rpm as soon as possible
Their workaround for this is the ECT mode. It behaves much more like a typical AT in that mode but it loses MPG. ECT has much quicker throttle response too.
Some wonder why ECT isnt the default with an ECO mode but ECO buttons dont count for EPA. The normal behavior is what the EPA goes by.
Solution: on manual get a pedal commander/sprintbooster. On auto either use ECT all the time or get a tune.

And i am wolling to bet the Gen4 is going to be a hybrid (not a PHEV or EV) since that would actually solve these problems. Kind of like how they added a starter gear to the CVTs. I just hope they dont go the turbo 4 cylinder route that so many cars use these days.

 

3500 in 4th and you can see t4r and 2gen with their "truck" engine in the rear mirror on the mountain pass.

 

OP here,
Since this has been bumped again, I’ll point out that I have now tuned the truck and am reasonably happy with the outcome.

MPG’s are still subpar in my opinion for the limited power these trucks make, but that’s really not a fault of the transmission.

If your content with how your truck drives, That’s great! I’m happy for you, and would encourage you to leave well enough alone.

If you feel there are better shift parameters available, I would encourage you to tune it. You can always go back (but you likely won’t).

 

Yep, the the shaft is bent and the rear end leaks. You can fix that fast with an oily rag. Use a nail to start her, I lost the key. Don't pay attention to the whirly sound, she uses a bit of oil, outside that she is Cherry.

 

I don't think I've had any gear hunting issue. The one I noticed the most is the lag on the throttle. I just got the pedal commander two days ago and I'm pretty happy with the throttle now.

 

Not the ETC (Tow / Haul) button but rather a dedicated “ECO Mode” button for running the stock low emissions ECU programming for milage from the factory. Otherwise it should come with the ECU programmed like a tune. The Term Toyota engineers use for the factory ECU drivability is force value. Basically the engine and transmission have a discussion to try and get the best mileage/performance and emissions as possible.

 

Personally I experience 1 mpg better with my 3rd gen tacoma vs the 2 2nd gens I had. Im thinking from a mpg standpoint Toyota could have just upgraded to the 4.0 version from the 4runner with the dual vvt along with the 6 speed auto in the current tacoma and gotten the same or slightly better mpgs as the 3.5.

Of course with the 3.5 being the smaller engine and having newer tech, it might produce less emissions than the 4.0.

 

This is so right. We have a ‘17 4runner with the “beloved” 4.0, and comparing it to my ‘21 Tacoma, the 4runner is slightly quicker off the line in 1st gear, I’ll give it that. But… the 3.5 in the Tacoma is noticeably quicker and more responsive throughout the entire rest of of the range. Once you hit 2nd gear and beyond, the Tacoma smokes our 4runner, pretty easily too. Passing someone on the freeway going 70+ mph is much easier in the Tacoma. And like you mentioned going up a mountain pass, the Tacoma has that extra power to tap in the 3000-4000K RPM range without needing to downshift… Where the 4runner is pretty much tapped out at that point, unless you make it downshift and push that needle into the 5Ks. It might sound crazy to some, but from someone who has owned 3 Toyotas with 4.0s (‘06 Tundra, ‘16 4runner SR5, and ‘17 4runner Limited), I’ll honestly take the 3.5 over the 4.0 (put the pitchforks down, haha). I also get 1-2 MPGs better with the 3.5.

 

Yep. A few years ago and rented t4r in Arizona for a week -Phoenix, Sedona, Flagstaff. It did not impress me in the mountains.
Last time I passed t4r on the pass, I could hear his engine revving.just like you stated - it was tapped out.
Back to the tranny issue.
The tranny is fine, the issue is with the choked throttle, early upshift points, late downshift points and engaging a full lock on the torque converter at low speeds.
Also, in D mode there are a dozen of optimal transmission torque tables that set a shifting behavior based on the speed(high/low) and engine temps (hot/cold)
S mode has just one table.

 

I drove a Tacoma, Tundra, and Jeep Gladiator today while searching for vehicles. The Jeep 3.6L V6 and 8spd auto were surprisingly awesome. Firm shifts, plenty of power, and just an obviously better experience compared to the Tacoma 3.5 V6 and 6spd combo. The jeep had more power, shifted better, and no hunting for gears like the Taco did. I was embarrassed for Toyota.

But, the Jeep was horrible on the highway for steering, the seating position was torture, and the blind spot indicator broke on the test drive. So, no Jeep for me.