2nd gear bucking for 6MT

Hi all. Just bought my first Tacoma this week. 2018 TRD Off-Road 6MT. I've always liked them and finally pulled the trigger

I noticed that sometimes after shifting into second, the truck "bucks" during much of my acceleration in 2nd gear, and sometimes in 3rd gear. I've owned many manual vehicles and never noticed this before.

Any ideas?

Thank you

 

It’s “normal” for a stock 3rd gen MT, but it is fairly easy to fix

1) accumulator delete
https://www.tacomaworld.com/threads/mt-accumulator-delete-mod-adm-and-bs-thread.568303/
2) tune
https://www.tacomaworld.com/threads/vf-tuner-for-the-3-5l-tacoma.662948/

 

This is a very timely thread, twice this past weekend my Taco did this in second gear; both times were in second going-up steep hills. I'd been on the fence about the ADM Mod but now I'm going to plan on doing it. Hopefully that eliminates the problem.

 

Besides the accumulator, the next thing is not accelerating hard in 2nd gear when below 2k rpm.

Meaning you need to ride first gear out above 4k before shifting.

The next thing I've found to cause the large lumps.

Knock from lugging the motor coming with a timing reduction.

Throttle limitations in the factory programming causing "steps"

And a switch from port fuel to direct injection.

Keeping the revs up helps avoid those scenarios. By keeping you above the lugging range and into the direct injection range.

Vf tuner can help eliminate those other issues as well.

 

If its bucking after you're already fully off the clutch you might want to try revving first gear out more. Second doesn't always like to accelerate hard in lower rpms. If it occurs while shifting just be real smooth off the clutch, second can take a little more getting used to compared to the others.

 

I give a brief pause with the pedal about 90% out to let the accumulator catch up and it has completely eliminated the surging. Took me about a week of driving this thing to get smooth with it, but it’s muscle memory now. I generally shift out of first ~2500 rpm unless I’m in a hurry.

 

Mine does it when cold, after pulling up a hit at the end of my street. When warm, it does not do. Like others said, a hair higher (slow when cold) rev in 1st gear helps. I feel like this is not an, "issue" and normal.

 

Rev first gear close to 4 k rpm before shifting ,rev 2 nd to 4 k to lose the jerk on your ass at the stop light .
As you start nearing 4k rpms in 2 nd it feels like a turbo kicked in .

 

The issue is actually the choice of gear ratios Toyota decided to use in the RC-62F. That's quite a big leap from 1st to 2nd for this engine.

 

Any thing below 2,000 rpm time to shift to a lower gear.

 

Wow, thanks for all the responses. I never posted in a forum before. I had no idea how helpful this would be. You guys are great

 

It always surprises me how much variance there is in when/how people shift. For me, I'd never shift out of first that early. That'd put you at about 1250 rpm in second; not a great spot in the power band for this engine. But that's the beauty of the manual, you can shift whenever/however you please.

I don't think I could retrain myself to get along with the accumulator. I'm pretty much a stock guy and trust the engineers decisions, but the accumulator just 100% sucks.

 

Can someone give a bit of an (scientific) explanation about why ADM helps with bucking? Maybe I'm thinking of a different problem entirely when discussing bucking, but when I've experienced it, it's as @jetspeed describes. Only when cold, and if I ease off the throttle and re-approach more gently, it stops. If I re-approach and put the hammer down, it bucks again.

Case in point, this doesn't seem like an issue with the clutch at all to me, since the clutch should be fully engaged at this point. Unless I'm DRASTICALLY underestimating how much the accumulator slows things down.

 

Someone else will be able to better explain this, but I'll try.

What you're describing doesn't sound like it's due to the accumulator. Once the clutch is fully engaged the accumulator has already done its job and is irrelevant. The bucking is due to some combination of engine tune and driveline slop. I'm on stock tune. It does not like it when you stomp on it. Rolling onto the gas is much smoother and often provides better acceleration since the engine doesn't fall on its face.

 

I think you are accelerating too hard and the engine has too make a rough VVT adjustments.

 

Thanks for the explanation. That's kind of what I was thinking. I've never had a manual not do this, and you just kind of learn to finesse your way through the gears in a way that the drivetrain likes. Usually that combination of revving higher and easing onto the throttle.

 

I did the ADM and this still happens to me sometimes. I have not got my Taco tuned yet but will do so in the future. As people here mentioned, shift out of first a little higher in the RPM and the problem goes away. My shifting dynamic changes depending on if I feel like saving gas or not. It is especially embarrassing when it happens with passengers in the truck. I swear to them that I can drive this thing haha.

 

After break in with the vF Tune, I can cruise smoothly down to 1k - 1,100rpm in any of the upper gears.

I often shift around 2k to 2,500rpm.


The Stock tune just sucks, but @AO1 might want to try the latest TSB Tune, 04B72.

 

I have got to ask what is with the accumulator? I have been driving for 59 years only owned a couple automatics that I didn't keep long and I'll be damned if I see even the slightest difference in my 2011 Tacoma 6 speed over the others even the old 87 Toyota truck. I can speed shift it fast enough to light up the tires (tend not to do that real often) so I don't get it what do you guys think you gained? Not being critical just curious.

 

Here you go:
https://www.tacomaworld.com/threads/mt-accumulator-delete-mod-adm-and-bs-thread.568303/

Lots of pics and info in the 1st Post.


The accumulator slows the engagement and makes it more vague.

Most folks are surprised by the positive effect of the ADM, but there are some who feel that there is not much difference. Just a thing.