Goodtimesgonebad
New member
Since I only notice it after highway driving I'm not sure it's just a rattling of the muffler, otherwise I'd hear it even after city driving. Could it be oil pressure dropping?
Knocking noise when in gear
- Thread starter Ace_Laserna
- Start date
Goodtimesgonebad
New member
After driving it tonight I noticed the noise got louder when put in reverse. Disappears when put in Park and Neutral though.
XJeepguy
Member
Sounds exactly like what mine is doing , when in Park and Neutral nothing, but when in gear it sounds like a whining or whirring sound . I'm 99% sure its the torque converter .
After doing plenty of reading its also a very common thing in 3rd Gen's .
AntleredRuin
New member
I've had this issue since I bought my 3rd gen 2+ years and 45k miles ago.
I'm 99.9% sure it's my AC compressor.
Turn the AC off, not just down, and see if the knocking still occurs. When you turn the AC off, it disengages the clutch and lets it free spin on the compressor.
The noise goes away completely when I have my AC turned off, and I also removed the AC belt and the noise went away that way as well. I believe it's a bearing in the compressor pulley, but it's such a pain to remove the compressor (evacuating and recharging the freon) that I figured I'd wait for it to completely die. 45k miles, and the AC still blows hard and cold, so I'm just going to let it knock.
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I'm 99.9% sure it's my AC compressor.
Turn the AC off, not just down, and see if the knocking still occurs. When you turn the AC off, it disengages the clutch and lets it free spin on the compressor.
The noise goes away completely when I have my AC turned off, and I also removed the AC belt and the noise went away that way as well. I believe it's a bearing in the compressor pulley, but it's such a pain to remove the compressor (evacuating and recharging the freon) that I figured I'd wait for it to completely die. 45k miles, and the AC still blows hard and cold, so I'm just going to let it knock.
Sent from my SM-G900V using Tapatalk
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thecole1098
New member
Mine does this in reverse too once warmed up. It's normal and nothing to worry about on these.
As for those that have a ticking sound when in gear, I'll bet the sound is the loudest around the bellhousing indicating a cracked flexplate.
Goodtimesgonebad
New member
Mine makes the noise when the AC is off so it's not that. I haven't had a chance to have someone pinpoint the exact location for me but it sounds like it's coming from the drivers side.
XJeepguy
Member
Yours doing it in drive and reverse ? The more I read the more I come across this complaint of a 'whining or whirring ' noise in gear , but quiet in P and N .
Mine never used to do this so something changed inside that torque converter . I've also read about this noise being present for 100K and still going . It's just an annoying sound ( especially after putting my new muffler in LOL ) . Its been loud for a year so I'm really noticing this sound now.
Be great to hear something from a Toyota tech , it's definitely a popular issue .
XJeepguy
Member
Your serpentine belts only whined in Drive or Reverse and not in Park or Neutral ?
thecole1098
New member
Mine only does it in reverse, not any other gear. And I'm a tech at Toyota actually and it's a pretty common sound with these 3rd gens and even newer cars, like Corollas, but those transmissions are way different obviously.
XJeepguy
Member
Have you , at your shop , ever experienced any torque converter failures in any 3rd Gen 4Runners ? Just curious , thanks .
thecole1098
New member
I've only been there for about 5 months now, but nope. Come to think of it I don't think I've ever seen a transmission or engine replacement on these trucks yet. The most I've seen with these transmissions are lock up solenoids not working. Other than the pink milkshake issue, these trannys are bulletproof.
XJeepguy
Member
There wouldn't be any noise associated with a failing lock up solenoid huh ?
thecole1098
New member
The part that goes bad typically is electronic, so no. It usually throws a P0740 code and you'll notice that around 50MPH your RPMs will never drop about 100 once the clutch is supposed to lock up, which will also contribute to increased fuel consumption. Shuddering around this speed is also a symptom of the lockup clutch itself being bad inside the converter.
Typically with torque converters they will make a distinct whining sound, almost like that of a power steering pump that's low on fluid, that gets quieter as the wheels begin to roll from a stop. Rattling is also a sound that can be heard if the stator is beginning to crap the bed.
I suppose the moral is: don't fix it if it ain't broke haha. As long as the transmission isn't slipping or shuddering when moving at a constant speed you'll be fine.
Trojan4x4
New member
They didn't wine, but knock, like bottom end crank knock.
Once I replaced the belts the knock went away, weirdest thing ever, I though it was internal engine too.
I even though it might be torque converter knock, it was very loud. But for some wierd reason belts fixed the noise.
thecole1098
New member
They were probably too tight before putting extra stress on the No. 1 bearing. I’ve seen it happen but usually once the damage is done putting new belts on doesn’t help. I guess it depends on how long it was like that.
XJeepguy
Member
Yeah that's what mine sounds like . Like my dog when he's hungry
KarlitosWay
New member
Sorry to revive an old thread - trying to chase the post-reply count so I can make this its own post.
Went a little off-roading this weekend in my 99’ SR5 and in the midst of a climb I noticed that my engine was losing some power and had suddenly become a lot louder. There seems to be a bit of a knock or misfire in one of the cylinders. Drove it 400km home so it can’t be too fatal. I’m assuming one of the spark plugs got rattled loose and is now missing because that’s one of the only things I haven’t touched about this truck since I bought it. But keen for any advice on what else I should be chasing.
Timing belt is solid, battery is solid, fluids are perfect, no leaks besides a bit of a rear diff leak.
Any thoughts or experience is highly appreciated.
Went a little off-roading this weekend in my 99’ SR5 and in the midst of a climb I noticed that my engine was losing some power and had suddenly become a lot louder. There seems to be a bit of a knock or misfire in one of the cylinders. Drove it 400km home so it can’t be too fatal. I’m assuming one of the spark plugs got rattled loose and is now missing because that’s one of the only things I haven’t touched about this truck since I bought it. But keen for any advice on what else I should be chasing.
Timing belt is solid, battery is solid, fluids are perfect, no leaks besides a bit of a rear diff leak.
Any thoughts or experience is highly appreciated.
My buddy and I bought a 4Runner about 2 years ago as a project. 169K on it and this noise was present when we bought it. Turned out it was a cracked flex plate. Replaced with an aftermarket flex plate and 4000 miles later and the noise is back. I've owned alot of 4Runners over the years and all have been super reliable including the trannys......not sure whats going on with the flexplates cracking???
