Transmission clunk when accelerating

Fumbler

New member
I've searched but could not find anyone with a similar problem.
The vehicle is a 2003 4Runner, V8, 4WD, with 93,000 miles.

I've had a transmission clunk feeling/sound while trying to accelerate.
This has happened a handful of times over the last couple of days (I avoid doing it if I can).
If i coast at 10-15mph, then give it some gas, the transmission will make a sudden hard jerk/clunk that can be both 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 normal otherwise.

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

I'm a lil overdue for a transmission fluid change so I'm going to have them take a look when it's being serviced.
In the mean time, has anyone had this problem?
Anyone have a suggestion on what it might be?
 
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Ahhh sounds like this might be the infamous "zerk fitting needs greasing" I've been reading about on here. So a search for "zerk" and you'll see posts (mine as well) about clunking when accelerating.
 
This is not the drive shaft clunk. I'm familiar with the driveline clunk and this problem I have feels different and only happens when the 4R's coasting slowly and I press the gas.
It's not that.
 
I have the same issue, as does everyone else on here. I've searched and found some good information, suggest you do the same, but there's nothing that can be done. It's essentially a laggy throttle response, you're coasting, then give it some gas, a half second later it realizes it and gases it causing it to "clunk", it feels like the 4runner is in neutral and then being thrown back into gear, I HATE IT. I've learned to all but eliminate it by changing my driving style. Whenever I'm coasting and need to gas it up again, I just give it a TINY bit of gas (not even enough to keep it at speed) for a second, then gas it, that gets it back into gear softly without clunking, then it's ready for smooth accelerating. I wish I could just have a freaking manual 4th gen 4Runner, conversion anyone?
 
I have the same issue, as does everyone else on here. I've searched and found some good information, suggest you do the same, but there's nothing that can be done. It's essentially a laggy throttle response, you're coasting, then give it some gas, a half second later it realizes it and gases it causing it to "clunk", it feels like the 4runner is in neutral and then being thrown back into gear, I HATE IT. I've learned to all but eliminate it by changing my driving style. Whenever I'm coasting and need to gas it up again, I just give it a TINY bit of gas (not even enough to keep it at speed) for a second, then gas it, that gets it back into gear softly without clunking, then it's ready for smooth accelerating.

:iagree: (except for the manual transmission part)
 
sounds familiar.......just like thirstyT said you pretty much just have to change that driving style. Add that and a 2000lb boat behind you and you will learn to accelerate very very softly real fast :lookout:. That's about the only thing I hate about the 4runner too
 
Thanks for the input.

But...this is a lot more than a simple lagging throttle response.
The clunk is hard enough to make it feel like you just got lightly rear ended and loud enough to make you think something just broke.

I put 25k miles on a different 2003 4Runner (it was brand new at the time), swapped for a Tundra, then swapped that for my current 2003 4R which I've driven for the last 18k miles.

I guess my point is this is a new problem. I know how 4Runners normally lag and I know how the driveline clunks. My driving style hasn't changed and the 4R's hadn't done this in the last 18k miles that I've owned it.

I got my mechanic at work to sit with me on a short drive. He used to rebuild GMC transmissions for a living and says it's probably a bad solenoid.
I guess all there's left for me to do is bring it to a shop (which I planned on doing anyway because it needs to be serviced).

I'll update this thread when I find out what's wrong.
 
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I just had the similar problem

Mine is 1998 SR5 4WD with 170K miles.

My 4 Runner had been performing fine until yesterday when I went to ski and used H4 on snowy roads. After I came back today and switched back to H2, I started to feel and hear this transmission clunk when accelerating at higher speed. I am pretty sure I did not have this problem before yesterday as I've been driving this same 4 Runner for past 12 years.

I just wonder if this new problem is related to:

1). using H4, or
2). cold weather, or
3). muddy snow on the drive train ???

What do you guys think?
 
It's been six years and 25k miles since I posted this thread and I feel a responsibility to contribute to the community, so here's what I found.

About a year/5k miles after posting this thread I had the transmission flushed along with other unrelated work done. It did not fix the problem.

Since then the problem has gotten only a tiny bit worse as it's easier to induce the clunk. I've adjusted my driving to avoid the clunk three different ways:
-giving it more throttle than necessary to make the vehicle downshift (works at higher coasting speeds)
-backing on and off the throttle until it decides to downshift by itself (works at slow speeds, less than 40 mph)
-lightly backing off the throttle and shifting the transmission selector into 4th gear then shifting back when I'm ready to coast

Last month (because I had a spare vehicle at the time) I finally decided to pony up the money for the dealership to do an actual inspection of the transmission. Mileage was 118k.

The mechanic told me he had to drive it four different times over three days to finally get the transmission to make the clunk and diagnose the problem. He said it's a worn/damaged internal clutch that was likely caused by something traumatic such as towing something waaay overweight.

I've never towed anything but I have pulled the stumps of a few small trees. However, whenever I've done this I've used a snatch strap, got the vehicle up to speed, backed off the throttle, and let the momentum of the vehicle yank the stump out. I explained this to the mechanic and he said that probably didn't cause the damage; it would have had to be pulling something while the drive train was under a huge load. I've also been in a collision where I was rear ended at about 7mph by a mid sized sedan (no damage to me other than scratches on my tow hitch shackle bracket, lol). He also didn't think that caused it.

The only thing I can think of that could've caused the damage is an incident I had a while before I first noticed the issue. I was stopped waiting to make a left turn. The road cleared up so I started. The engine revved up and the truck didn't move, then suddenly it started as if the transmission wasn't in drive then popped in. That's the only time I've ever experienced that and it's the only time I can ever remember any sudden load on the transmission.

So...the mechanic's recommendation was to just live with it because a factory remanufactured transmission is $3k + $1k in labor. He believed I could drive it indefinitely the way it is and if it got progressively worse the vehicle would still function in the lower gears long enough for me to get it fixed.

Out of curiosity I asked the mechanic and shop manager how many 4Runner transmissions they've replaced. The manager said in the 5 years he's been there they've never replaced a transmission in a 4Runner and never replaced a transmission in any Toyota with a V8. The mechanic said he's been a Toyota mechanic for over 10 years and he's only replaced a handful in 3rd gen 4Runners and one or two in 4th gen 4Runners with the V6 after they've had a lot of towing miles. He also said he's never changed a transmission in any Toyota truck with a V8.

On a side note, I'm cheap. I've got a lifetime alignment at Firestone so I always have them do alignments. I had a popping noise from something in my front left for a while. I knew it wasn't a CV joint as it only popped when the suspension moved up and down. I couldn't find any play in the ball joints. The mechanic looked at that issue and found that the bolts used to adjust alignment were not properly torqued. He torqued everything to spec and I haven't had the popping since.
 
Thank you for the update, and sorry to revive a literally 12 years old thread lol.
I have been driving my 07 4runner SR5 V6 for its whole life in 2wd (Of course I practice 4hi and 4lo and locker every now and then), and just recently I learned that all of them have a torsen center diff so there's no problem of driving it in 4hi all the time. I feel like I've been missing for a significant feature in my rig, so in June I decided from now on I'm gonna drive it in 4hi only, and practice 2hi and 4lo instead, which can save me that 10-mile 4wd practice each month. I paid for a torsen diff, I use it.
In the same month, I drained and filled the whole driveline lube and ATF. Just in July, I noticed the same problem as the OP. Seems like the jerk does not affect 2hi at all: I've tried for a day finding that jerk motion in 2hi in stop and go traffic, yet I felt nothing. My initial conclusion is, yes the clunk is caused by transmission (my rig has 164k, but a LOT of it is in New York City traffic), but seems like it's amplified from the front diff or the transfer case. For me though, it rarely happens even in 4hi, so I'd just let it run 4hi until it gets much worse. I will update when I change the transfer case fluid and diff fluid and ATF, although I do wonder how many of us is still DDing a 4th gen.
 
Thank you for the update, and sorry to revive a literally 12 years old thread lol.
I have been driving my 07 4runner SR5 V6 for its whole life in 2wd (Of course I practice 4hi and 4lo and locker every now and then), and just recently I learned that all of them have a torsen center diff so there's no problem of driving it in 4hi all the time. I feel like I've been missing for a significant feature in my rig, so in June I decided from now on I'm gonna drive it in 4hi only, and practice 2hi and 4lo instead, which can save me that 10-mile 4wd practice each month. I paid for a torsen diff, I use it.
In the same month, I drained and filled the whole driveline lube and ATF. Just in July, I noticed the same problem as the OP. Seems like the jerk does not affect 2hi at all: I've tried for a day finding that jerk motion in 2hi in stop and go traffic, yet I felt nothing. My initial conclusion is, yes the clunk is caused by transmission (my rig has 164k, but a LOT of it is in New York City traffic), but seems like it's amplified from the front diff or the transfer case. For me though, it rarely happens even in 4hi, so I'd just let it run 4hi until it gets much worse. I will update when I change the transfer case fluid and diff fluid and ATF, although I do wonder how many of us is still DDing a 4th gen.

The slow down to low speed and drop out of gear problem is attributed to a faulty SLT pressure solenoid.

There's a bunch of links here detailing my years long saga on the problem:
https://www.toyota-4runner.org/3594255-post25.html

I wonder if [MENTION=31322]Fumbler[/MENTION] is still around the forums. I try to keep an eye out for these threads in the hopes I can save a few more trucks from this issue.
 
The slow down to low speed and drop out of gear problem is attributed to a faulty SLT pressure solenoid.

There's a bunch of links here detailing my years long saga on the problem:
https://www.toyota-4runner.org/3594255-post25.html

I wonder if [MENTION=31322]Fumbler[/MENTION] is still around the forums. I try to keep an eye out for these threads in the hopes I can save a few more trucks from this issue.

Thanks for sharing. That's a bummer, and mine is not deteriorating *yet*. I do notice it's basically symptom free in 2hi, which can actually stop me from noticing it if it got worse. I guess I do need to run it in 4hi everyday now, since front diff and t-case can amplify that vibration. Sucks for me not knowing I need to drain and fill the fluid every 60k even without towing, and believing that lifetime fluid thing for 10+ years. I'll do one last drain and fill and see how it goes. Fortunately as far as I know SLT does not "kill" the transmission but modulate smoothness? Fingers crossed.
 
Thanks for sharing. That's a bummer, and mine is not deteriorating *yet*. I do notice it's basically symptom free in 2hi, which can actually stop me from noticing it if it got worse. I guess I do need to run it in 4hi everyday now, since front diff and t-case can amplify that vibration. Sucks for me not knowing I need to drain and fill the fluid every 60k even without towing, and believing that lifetime fluid thing for 10+ years. I'll do one last drain and fill and see how it goes. Fortunately as far as I know SLT does not "kill" the transmission but modulate smoothness? Fingers crossed.

The symptom the SLT failure refers to, is if you're cruising along and then slow down to around 5-10MPH, then accelerate again, the transmission has "forgotten" to shift into first. So you've pushed in the gas pedal, the engine revs, and nothing happens 'cuz the truck's seemingly not in gear.

Then it suddenly jams itself into 1st gear, giving you and your passengers whiplash.

I never had any vibration and the truck drove normally... except for that one thing.
 

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