Tacoma - OVTUNE - VFTUNER - Update Info and Original Development

So I’m about 150 miles in on 1.02C, and I’m noticing when come to a stop my transmission has intermittent clunking downshifting to the lower gears. Has anyone else experienced this?

 

I frequently experience a decided and annoying 'clunk' when coming to a stop, as the tranny downshifts to first gear. Most frequent when the weather and the truck is cold (below freezing). I believe that it is related to the torque converter lock-up decoupling.

I have experienced it since the truck was new (28,000 miles ago), so it is not something introduced by the tune. I am hopeful that the next update will deal with it.


Frank

 

That is exactly what is happening to mine. Started noticing it after the tune and when it’s cold. My cold weather isn’t that harsh, maybe around the 30-40 degree temps. I was concerned that maybe my tranny fluid was low. But I don’t remember the clunk with my stock tune.

 

@OVTune - Hey man, hope everything is ok there.

 

It has nothing to do with the tune. Many have complain about this issue. Exp mine at deliver...

 

I’m not necessarily saying it is. But I started having this behavior after the tune. Truck still drives better despite everything though.
Could be a coincidence you never know.

 

I noticed a clunk after the tune also. I was coasting up to a red light, when I got down to ~10 mpg the light switch so I gave it gas and that's when it clunked. But it seemed like when I gave it gas it was just taking out the backlash in the drivetrain. It made me wonder if I hadn't noticed this before because the stock tune has no throttle response and now when I step on the gas the engine does something, except this time the drivetrain wasn't ready. It only happened that one time, tried to make it happen again but couldn't.

 

Maybe @OVTune can put his two cents in. I’m curious if this will be ironed out in the next update.

 

Clunks been there since rev 1 tsb for my truck. If you were on the 02 ECU TCU version and updated to the 03, you probably just got the same factory updates in the 03 that causes the clunk.

 

I’ve had the clunk as well. It’s hard for me to remember if I had it pre-tune. I’ve had both the getting-back-on-throttle clunk and the coming-to-a-stop clunk. Not all the time. As others have said, mostly when cold.

I remember noticing the getting back on throttle clunk much more when I was on 1.02c-A. Now that I’m on 1.02c-C, I only really notice the coming to a stop clunk. And when this happens, I’ve noticed it happens mostly in the “oh I can make this light.....wait no I better stop abruptly” kind of situations. Much more frequent under hard braking/stopping.

Like stated a few posts back by another member, I think and/or hope it relates to the torque converter lockup business....and it sounds like Mat plans to tweak with that. Hopefully it solves it.

In any case, what I’ve gained in drivability I think far outweighs the relatively small (albeit somewhat annoying) issue of this clunk. I do hope it can be worked out.

 

I’ve been running 1.02C since it was released. My trans also does this, only when cold though.

 

Appreciate the input and responses gentleman. I agree that the drivability more than makes up for the random clunk here and there. I plan to look into this alittle further and will report back should I find anything.
From the sounds of it the next update should really clean things up which could fix our issue we’re having.

On another note the truck really pulls harder and smoother then I ever thought would be possible. Hauling ass and having fun is defiantly a thing when you get this tune.

 

It's the Toyota Truck Tranny Thunk....every AT Toyota truck I've had since 1998 has it...some worse than others....my 2017 is on the worse end of the scale...up there with my 2002 Tundra.

 

Mine does the same at unpredictable times. Only when braking though. Both cold and at normal temperature. Sometimes it’s hard enough that the truck will shudder. Plus I haven’t done the tune yet. It’s definitely a Toyota thing.

 

Ditto on the clunk for me. I’m running the stock tune

 

I thought I read somewhere in another thread that it had to do with insufficient grease somewhere... maybe the drive shaft??

 

It's software related as it's temperature dependent and can be reduced/eliminated if you use ECT + S Mode. A mechanical defect would be present under virtually all scenarios.

 

Someone a year or more ago diagnosed the problem as insufficient grease in the driveshaft splines. I subsequently greased mine, and it made no difference.

Frank

 

Yes - my 2011 did it a little when coming to a stop. seems to have something to do with the driveline splines/unloading/loading and may be connected to the leaf springs as they flex and move when breaking. My 2017 does it prior and post tune.

 

My truck has made this clunk from the day I picked it up, if you're referring to the clunk that can be heard towards the back. Been pre and post tune. The clunk happens when the truck first starts to move from a stop.


I can see what you guys are talking about on throttle response 1rst gear on 1.02C-A. Needs to be tweaked slightly.