2.7 with the 6 speed auto

Nice setup on the transmission cooler, i'm planning on installing one. I'm contemplating eliminating the radiator and running the cooler only. Your setup it shows the hose go to the cooler horizontally, just for clarification your "inlet" is the top and "out" is the bottom? Reason for asking, when I was doing some research I came across these images below. To prevent air pockets the inlet is recommended to be at the bottom.

 

I have always mounted my coolers sideways and the inlet top and outlet bottom. Ive put them on hot rods to tacomas that way without any issue. In theory I guess it could but also more strain on the pump. The stock configuration is inlet top of radiator outlet on bottom for what it’s worth

 

Had lateral meniscus surgery on both knees over time but when it was my clutch leg, I was stubborn enough to just use my right foot for both acceleration and clutch instead of finding a new vehicle to driver for a while...

 

Gonna chime in for the folks in the future that may run across this.

I traded a 19 Frontier for a base 2WD SR. Just wanted a grandpa truck that would outlast me, and this was the last chance to get the basically indestructible 2.7.

While it's fine on the 2-lane back roads, it is aggravating to drive on the highway. Constantly bouncing back and forth between 6th and 4th, like 5th gear doesn't even exist; especially if there was any sort of hill. Downshift to 4th, upshift to 6th to find it doesn't have enough power, and kick down to 4th again.

3/4 of the pedal travel seemed to do nothing. Cruise was essentially useless.

13k miles of aggravation to date. I considered regearing. I considered the OTT tune I see here. I considered getting rid of the truck.

On a whim, I plugged in my scan tool and erased the transmission memory to force a relearn. I didn't do that in the past, because I was under the impression it was always learning.

It drives awesome now. It now seems to know there is a gear between 4th and 6th, and it uses it. Rough downshifts to 4th are gone, and everything related to the drivability is vastly improved.

So to answer the question, it's fine. If it shifts weird, have the dealer reset the memory or buy a scan tool and do it yourself (I have a $400 Otofix that uses Autel software).

 

I have a 2023 SR 2.7L 4x4 with the OTT tune. Most of the shifting issues were resolved with the tune but they seemed to come back. The truck likes to slide into 5th when it should be in 4th which it didn’t seem to do after I installed the tune. I’ll see if my scan tool can erase the memory and see if that helps.

I’m highly considering a 5.29 regear. I bet that would solve the issue entirely with a complementary tune for the new ratios.

 

Ultimately I didn't do the regear because it increases the driveshaft speed. That's why you see folks complaining about their top speed / highway speed being limited.

The 4-banger has enough power for what I use the truck for, and I'm a Gen-X'er who grew up with 4 banger Toyota pickups, and have owned a '93 and one of each generation Tacoma at one time or another. I just wanted this transmission to stop yo-yo'ing from 4th to 6th to 4th to 6th on the highway/interstate.

I've been driving it for a week now after the memory erase (that's the option when the tablet is hooked up to the taco - on the wife's subaru it's "relearn"). It drives like a normal automatic transmission now. It even gets a little better gas mileage.

 

I’m not concerned with the driveshaft speed since the final drive ratio is too tall for the power of the engine and the way the transmission is geared. My 2.7L only slides into 6th if I’m going downhill on the highway or when I’m driving significantly faster than I normally do flat stretches of interstate. Other than those two specific circumstances, 6th is just too much for the 2.7L to turn. I live in MA and there are a lot of hills in my area. Even with the stock wheels and tires I can’t use 6th for anything really. I usually drive in S5 to prevent the truck from *ever* selecting 6th since I can realistically only hold that gear for a few moments at a time around here.

With a 5.29 regear, both overdrive gears would be more useful and an updated OTT tune would eliminate any top speed limitations. For someone who doesn’t plan on ever exceeding 90mph in their truck for long periods of time, I think the 5.29 regear is a no brainer for 2.7L trucks (unless you live in a very flat area, never tow/haul much of anything, or are afraid to tune the truck for whatever reason).

 

Driveshaft speed is important because they're rated for a certain speed (RPM). Exceeding the rated speed can cause everything from vibration to failure. A broken shaft or universal joint can range from an annoyance to a deadly problem. Point being it's not something to disregard or override. You have to take it into account. Either don't exceed it or get a higher rated shaft (which probably means having a speed shop fabricate one).

I live at the edge of the Ozark plateau. There are a lot of hills here too. Usually that means two-lane twisty roads where you're only going 50-60, and the stock gearing is adequate. The 2.7 runs out of grunt at interstate speeds, manly because the drag of the bloated body at those speeds.

 

What you’re saying makes complete sense and is perfectly logical, however, I don’t think you’re taking into consideration how much of a change 4.30 to 5.29 actually is.

By gearing to 5.29, the final drive ratio is increased by about 18.7%. That means that the speed of the driveshaft at 80mph with 5.29 gears is equivalent to the speed of the driveshaft at about 95mph with the stock 4.30 gears. As someone who barely ever exceeds 75mph in his truck, I’m more than comfortable with that drivetrain RPM. If my calculations are off here, let me know.

In my area, 50mph-60mph just isn’t safe on the highway. I need to be in that 65mph-75mph zone while climbing these hills to avoid causing excessive passing from other cars and the dangers associated with that. Giving the 2.7L the additional leverage of 5.29 gears seems to be the best way to prevent the truck from lugging 6th gear and kamikaze-ing down into 4th gear for the steeper grades. I’d reckon that it’d turn 5th gear up my steep hills at 70mph without issues if I had that shorter ratio.

 

I have 5.29s changes completely how the truck drives. 4th has a ton of power climbing steep grades. I live about an hr from the mountains and climb at 6% grade at 60-65 in 4th with cruise control on but it can still struggle in 6th and 5th up some grades or a headwind. It’s a night and day difference but not perfect and I would 100% pair it with an OTT tune. If I were doing it again I might have went 5.71s I believe ecgs offers. That I believe for a 4wd heavier truck would be the ideal. I also have a tire size up small lift and about 600lbs heavier than stock with a topper. It does surprisingly well and decent mileage too I can get 23-24 going 65-70

 

I’m sure 6th gear is actually useful now that you have the leverage to turn that gear on anything other than a flat stretch of road. What are your RPM’s at when you’re in 6th around 75mph? Also, what size are your tires exactly? Thank you for chiming in.

 

I can go up slight grades in 6th it’s still slow just more normal feeling slow. I had 265/75/16s and now I run 235/85/16s. The truck likes the same height thinner tire. Keep the weight down and the tire size minimal with the 4 cyl.

 

That looks perfect to me. I’m still on stock tires though. So my RPM’s would be a bit higher at those speeds.

 

Yeah I think it will be 1-200 rpm’s higher with stock size tire, will be perfect for a stockish truck. 4.88s would not have been enough if you were thinking about modding it 5.71’s would be in consideration. You won’t be disappointed in the regear.