Transmission Clunk when Accelerating

tysauce

tysauce

New member
New to this forum as I've only had my 4runner for about a month! Vehicle is a 2007 Sport V8 with 116,000 miles.

I've searched quite a bit and found some good info, (seems to be a common problem with Toyotas) but was wondering if there was any resolution to this issue for 4th gen 4runners? Or if it's something that I shouldn't be concerned about?

I've been having a transmission clunk feeling/sound while trying to accelerate.
This has happened a handful of times over the last couple of weeks. (I avoid doing it if I can. I'm able to pretty much eliminate it by changing my driving style, but it's still annoying regardless).

If I coast at 10-15mph, then give it some gas, the transmission will make a sudden jerk/clunk that can be heard and felt.
It feels as if the transmission is not in gear when I press the accelerator, then it pops into gear.
It happens mostly when I slow down quickly, let it coast for half a second, then press the gas.
The vehicle feels completely normal otherwise and shifts like a dream.

This is not the drive shaft clunk. I'm familiar with the driveline clunk and this problem feels different and only happens when the 4R's coasting slowly and I press the gas.


Has anyone had this problem? Has there been any fixes issued from Toyota that anyone knows about for the 4th gen? Or are people just living with it?
 
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It doesn't seem to be the drive shaft, I'm familiar with that clunk and have already resolved that issue with grease. This is one within the transmission for sure.
 
The transmission seems to go into neutral between gears sometimes. My theory is that it always does between 2-3, but I have not paid enough attention to confirm yet. Sometimes when coasting the RPMs drop, like it's in neutral or something. Or maybe it's just unlocking the torque converter and it's being driven in reverse by the drive side turning faster than the engine side (normally the engine side turns faster, like when you are at a stop). Maybe when you press the gas after coasting something has to change speed, or it has to engage the gear again.

Maybe if it's momentarily in neutral and you start to accelerate, the torque converter spins faster but it's not connected to any gears. The transmission senses that you are trying to accelerate, so it quickly reengages one of the gears before the engine gets spinning too fast. Doing so, the output side of the torque converter suddenly slows down since it's no longer freely spinning, and its momentum is transferred to the drivetrain, resulting in a clunk. This is all speculation.

Basically, automatic transmissions are complicated, and without knowing how it was designed we don't know how it's supposed to work or what it's actually doing at any given time (it would be cool to have a bunch of indicator lights to watch it! Like one for each solenoid or circuit). They have weird behavior sometimes, and it's probably normal. It seems well designed, given the fact that they can last a very long time, so it's unlikely that anything you can do in normal driving will damage it.
 
The drive shaft issue comes back. It isn't just a do it once and it lasts. For mine it needs to be done almost every oil change. I'd suggest greasing the driveshaft (even though you think it isn't the issue) and then move on from there. It is a simple and quick item to eliminate.

Other than that, a transmission fluid flush may do the trick. It all depends on the miles and use your vehicle has seen in the past.
 
tysauce said:
It happens mostly when I slow down quickly, let it coast for half a second, then press the gas.
Click to expand...

Normal.

(The obligatory series of posts saying, "mine doesn't do this" in 3..2..1

m85476585 said:
. It seems well designed, given the fact that they can last a very long time, so it's unlikely that anything you can do in normal driving will damage it.
Click to expand...

This
 
Yes, I know what the driveshaft thud sounds/feels like and this was definitely a different clunk. This clunk was happening under different driving circumstances than the classic driveshaft thud too. I really do understand the driveshaft issue and have the maintenance under control.

From what I've researched though, and from what you all have said it does sound like this is a normal occurrence in these transmissions and I should have nothing to worry about - especially under normal driving conditions. Glad to have to some support to set my mind at ease! It seems to be more of an annoyance than anything.
 
other ways to check is remove your rear drive propeller and put it in 4 wheel drive. drive it and test it again. it is possible that it's your rear differential gear has a broken teeth.

also, check if your transmission has the correct level.
 
I so far have had my differential fluid replaced, transfer case fluid replaced, driveshafts greased, and the issue seems to persist. Would a transmission fluid change help?
 
Johns06yota said:
I so far have had my differential fluid replaced, transfer case fluid replaced, driveshafts greased, and the issue seems to persist. Would a transmission fluid change help?
Click to expand...

So it's been a few years since I posted this. I have done 3 drain and fills since this post and the "issue" will still happen from time to time in stop and go traffic. I have honestly just learned to drive around it and not worry about it. Like I said, it's been years now and I have noticed NO noticeable difference in operation. Like some posts mention above, I don't think these transmissions are easily deterred. Very solid. Let me know if you have more questions though!
 
tysauce said:
It happens mostly when I slow down quickly, let it coast for half a second, then press the gas.
Click to expand...

I've had my truck for 4+ years... and it's only recently that it's started doing this. Maybe... maybe I just never noticed it, or it happened so rarely I didn't take note. Lately I seem to notice it doing it often enough that I do have different driving habits to avoid an unplanned chiropractic adjustment.

Anyway, after a fluid change had no impact on the problem I took my local Toyota Tech for a cruise and got the transmission to do it a couple of times for him with his code reader attached. No codes, no abnormalities. All systems normal. No extra charge for minor case of whiplash.

If I recall correctly, one guy posted in a thread about replacing a shift solenoid. He did not specify which solenoid or which code he had. Likely irrelevant in my case because I don't have any codes.

Aside from occasional soft tissue injuries and the rare AWD burnout, it's mostly only an annoyance to me. However, sometimes it catches me off guard when I have passengers and I scare the crap out of them... the sensation is similar to being rear-ended.

I'm currently waiting to gather a second oil sample from the ATF to send for analysis. I have one sample with ~20000km on it, and another will have around 10000km. Hopefully there will be enough data to indicate if there's a problem going on inside... a mechanical problem would be a much simpler fix.

If there's no indication of problems from the oil analysis, I'll contact IPT and see if their valve body upgrade will impact that characteristic. If they're not sure, I could slap in the parts and see. If it changes the problem, it was a hydraulic characteristic of the factory valve body system.

If none of that works, the newest version of the sprint booster can play with shift patterns, and set on its most aggressive setting, it might reduce downshift time; making the problem much more subtle.

For what it's worth, my truck is an '05 Limited V8. It'd be nice to know if the V6 version does or does not exhibit this characteristic.
 
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