Buzzing/Rattling noise when pressing the accelerator at >60 mph

[lycaon_guy]

I got a 2002 SR5 with just over 81k miles this past week. On our low speed (<45 mph) test drive everything sounded great. When I got on the freeway to drive home though, I found this buzzing/rattling noise whenever I stepped on the gas. It starts at about 60-65 mph and is only present when I'm holding down the gas pedal. It shows up no matter the RPM, but it seems to get a little quieter when the RPMs are up about 4500. Sometimes I hear it faintly at about 45 mph, with the RPMs at about 2500. It seems to be coming from down below the shifter/center arm rest.

I've searched and found a few threads, mostly suggesting a loose shield somewhere on the exhaust system or a dry driveshaft. I checked the exhaust system and it doesn't seem to have any loose parts. I also greased the zirks on the driveshaft. The sound is still there.

This (https://www.youtube.com/watch?v=wesBnIVBUc0) is a link to a video I took. It starts at second 6-17, I take my foot off the gas for a moment at second 17 & 22.

Any ideas?

 

[Arrowhead]

I can't say one way or another what it would be, but I do know that I am buying a 99 4runner this week, checked it out tonight, that has a broken flexplate. The lady said she daily drove it and for a while, heard a funny ticking sound, rattle sound, or "odd" sound as she put it, but it still drove quite a while. They were replacing everything but that, lots of new parts. Finally the flexplate broke and it stopped on her, sat since. I am tackling that this week and just thought I'd mention the flexplate can make sounds that can be misdiagnosed by some. I personally haven't had this issue in the 5 3rd gen 4runners I've owned, but I've never had any buzzing, rattling issues with my 4runners. Maybe check into the flexplate? It has plenty of info about the flexplate issue as well as youtube videos by others who have experienced the failure.

 

[absalom]

If I were you, I'd get a rubber mallet, slide under the truck and start banging around. On the surface, this seems like a pretty easy fix

 

[lycaon_guy]

I can't say one way or another what it would be, but I do know that I am buying a 99 4runner this week, checked it out tonight, that has a broken flexplate. The lady said she daily drove it and for a while, heard a funny ticking sound, rattle sound, or "odd" sound as she put it, but it still drove quite a while. They were replacing everything but that, lots of new parts. Finally the flexplate broke and it stopped on her, sat since. I am tackling that this week and just thought I'd mention the flexplate can make sounds that can be misdiagnosed by some. I personally haven't had this issue in the 5 3rd gen 4runners I've owned, but I've never had any buzzing, rattling issues with my 4runners. Maybe check into the flexplate? It has plenty of info about the flexplate issue as well as youtube videos by others who have experienced the failure.

Thanks I'll look into flexplate issues. I'd never heard of it.

 

[lycaon_guy]

If I were you, I'd get a rubber mallet, slide under the truck and start banging around. On the surface, this seems like a pretty easy fix

Okay, I'll try this tonight.

I checked the transmission fluid level last night and it was almost an inch over the top "high" mark with the engine hot, but not running. Do you think that might have an effect?

 

[Predatorhouse]

I think I know what you are talking about and I think its the heat shield on the headers. I put a intake on my taco and 4runner because they both did it exactly in the MPH range on highway like you stated, and the rattle went away. My thoughts is the motor isn't working so hard to breath after the intake. Just my two cents, you could also do the ISR mod and that may work as well.

 

[lycaon_guy]

I think I know what you are talking about and I think its the heat shield on the headers. I put a intake on my taco and 4runner because they both did it exactly in the MPH range on highway like you stated, and the rattle went away. My thoughts is the motor isn't working so hard to breath after the intake. Just my two cents, you could also do the ISR mod and that may work as well.

Thanks Predator. What do you mean by do an intake? Is this (Toyota 4Runner Highlander Deckplate and Air Filter Modification) what you're referring to?

 

[Predatorhouse]

A ram Air or cold or cold air intake. Like I said you can also do the ISR mod it deletes the parisitic boxes on the factory intake. Also some people put a marine cover on the forward facing side of the air filter box to force more air in their intake wile driving. You have to cut a hole in the factory air filter box for that mod, and also remember to put the cover on if it starts raining. This is just a sugestion. Maybe someone who knows more like Singtoe would be better to answer this question.

 

[Predatorhouse]

Sorry I didn't click on the link but yes and the first pic on their shows the parisitic boxes that i was talking about, you can replace that section with a large piece of pipe.

 

[gamefreakgc]

I agree on getting under there and bumping things around. I'm guessing it has less to do with the throttle and more do to with vibrations in the driveline that's rattling something around. Just tap and wiggle every part and do-hickey under there till you find it.

 

[lycaon_guy]

A ram Air or cold or cold air intake. Like I said you can also do the ISR mod it deletes the parisitic boxes on the factory intake. Also some people put a marine cover on the forward facing side of the air filter box to force more air in their intake wile driving. You have to cut a hole in the factory air filter box for that mod, and also remember to put the cover on if it starts raining. This is just a sugestion. Maybe someone who knows more like Singtoe would be better to answer this question.

I agree on getting under there and bumping things around. I'm guessing it has less to do with the throttle and more do to with vibrations in the driveline that's rattling something around. Just tap and wiggle every part and do-hickey under there till you find it.

Thanks so much, I'll look into intakes after checking the undercarriage for loose things more carefully. It's been raining so I haven't been able to get underneath and inspect it yet.



EDIT: I got underneath with a rubber mallet and wiggled and hammered on everything I could think of. The only thing that seem a bit loose is the center of the oil pan skid plate. The corners are solid, but the middle wiggles some. Is that normal?

The top nut of the driver side sway bar link was rusted off, and it was just seated up held by the rubber. Would that do it?

Nothing seems loose in the engine compartment.

 

[Predatorhouse]

The skid plate is real thin so I wouldn't be concerned with that being the noise unless its missing bolts, you can always take it off and drive it for a few days. You can even take the sway bar off as well its not going to hurt your vehicle, some guys ride without it for the xtra flex. I wouldn't do them at the same time so you can narow it down if the noise goes away.

 

[LookAtThatDog]

My trans started slipping last week and it sounds just like this. I swapped out fluid and it got quieter. I'm doing a flush this weekend. Mine was obviously coming from the pan at any speed

mine:

https://www.youtube.com/watch?v=Dy7Y6LWINYs

 

[Grenvilleter]

I did not listen to the clip but transmission hydraulic pump is my suspicion as well.

 

[lycaon_guy]

My mechanic and I took a ride over lunch today and he diagnosed it as something in the rear diff. There's been a slow leak from the top of the diff (weird I know) so I'm going to re-do the diff fluid and put in a new breather. Fingers crossed. The pinion seal seems to be blown too (oil thrown just behind the transfercase), so he's going to do that next week. Hopefully it'll clear things up.

 

[lycaon_guy]

My trans started slipping last week and it sounds just like this. I swapped out fluid and it got quieter. I'm doing a flush this weekend. Mine was obviously coming from the pan at any speed

mine:

https://www.youtube.com/watch?v=Dy7Y6LWINYs

Ouch! Did the fluid swap totally remove it? Mine only happens when driving.

 

[LookAtThatDog]

I drained the pan and refilled it and the noise is much quieter, no CEL, no slipping. I'm doing a flush this weekend. We'll see!

 

[lycaon_guy]

I drained the pan and refilled it and the noise is much quieter, no CEL, no slipping. I'm doing a flush this weekend. We'll see!

Good to hear! I drained my rear diff last night and the fluid was almost black...way overdue. The fluid looked a bit low as well. The magnet had about a mm of metal dust stuck to it, is that expected? No shavings or large pieces, just super fine particles.

It looks like the diff is weeping from the area around the L brackets for the parking brake and regular brake lines, so I sprayed it with some Permatex rust converter and am going to JB weld the area...hopefully it'll do the trick. Any other ideas?

 

[lycaon_guy]

I drained & refilled the front & rear diffs, as well as the transfer case. No change in the sound. I've started to notice a whine when I let off the gas as well. From searching around, it sounds like it could be a bearing, etc in the diff. Gah:brick: