Rear end whine at 65-70 mph

[ahtoxa11]

Guys, I apologize about cross-posting this. It seems the warranty/problems thread doesn't see much traffic

I have read some older threads, but wanted to see if there's any new info or experiences with this.

Starting around 65 mph I'm getting a slight whine seemingly from the rear end when maintaining speed or lightly accelerating. If I left off throttle it stops right away and when accelerating harder I can't really hear it due to engine noise.

I've read in previous threads that this is somewhat common and there wasn't any consensus on whether it's 'normal' or not. Any recent experiences?

Another theory I have is related to skid plates. I started noticing the noise around the time I installed a full set of aluminum skids. I wonder of they are bouncing more sound back into the cabin. I could remove them and test, but figured I'd ask first.

I do have an appointment at the dealer on Thursday, but thoughts would be great.

 

[fkheath]

Guys, I apologize about cross-posting this. It seems the warranty/problems thread doesn't see much traffic

I have read some older threads, but wanted to see if there's any new info or experiences with this.

Starting around 65 mph I'm getting a slight whine seemingly from the rear end when maintaining speed or lightly accelerating. If I left off throttle it stops right away and when accelerating harder I can't really hear it due to engine noise.

I've read in previous threads that this is somewhat common and there wasn't any consensus on whether it's 'normal' or not. Any recent experiences?

Another theory I have is related to skid plates. I started noticing the noise around the time I installed a full set of aluminum skids. I wonder of they are bouncing more sound back into the cabin. I could remove them and test, but figured I'd ask first.

I do have an appointment at the dealer on Thursday, but thoughts would be great.

First action, of course, would be to check the oil level in the differential and verify if it is the right kind of oil if it has ever been replaced.

Yes, added skid plates could change the sound you hear.

Differentials require careful adjustment of the gap between the pinion gear and the ring gear. Having too big of a gap, you can get whining. The gap is adjusted by spacers. With normal wear, the gap and the whining can increase over time. Some whining is not bad on the differential, only annoying.

 

[Tbasse01]

Mine has the whine at the exact same speeds

Every test drive I took in 4 different 4r's was the same including the 2020 TRD pro same whine as the 2016 limited I ended up buying

 

[ahtoxa11]

Good to hear, guys. Thank you. I’m sure the dealer will find a non issue today.

 

[71gs3504sp]

Good to hear, guys. Thank you. I’m sure the dealer will find a non issue today.

How about change the rear fluid and see if any heavy metal particles is in the oil? It only 3 quarts ($40-$50) and only takes a half hour, it just like draining the engine oil. I did mine at 15k miles and it was extremely dark, typical paste on the magnet.

 

[Tuco S.]

You said your odometer is around 27k. Did you grease the drive (propeller) shafts at 15k?

 

[Jemplyr77]

Same on my 2019 NS. Asked the dealer and they said it is normal characteristic of the 4Runner. My previous 2016 Limited did not have this issue though. I changed the fluid in the rear diff resulting in no significant change.

 

[Jeremy556]

Install mud tires and put 140w oil in the diff

 

[Matt831]

https://static.nhtsa.gov/odi/tsbs/2019/MC-10164329-9999.pdf

 

[delloro]

Install mud tires and put 140w oil in the diff

Or a better radio.

 

[BlakeA]

I have this exact issue on my 2019 4runner 2WD. The dealer replaced the rear differential and it made absolutely no difference.

 

[ElectroBoy]

https://static.nhtsa.gov/odi/tsbs/2019/MC-10164329-9999.pdf

Thanks for that link.
If I may ask, how did you find this?
Is there a master list of all Toyota TSBs that we can search?

 

[Matt831]

Thanks for that link.
If I may ask, how did you find this?
Is there a master list of all Toyota TSBs that we can search?

I had a free subscription with an online source until they were forced to cancel TSB access. Now I just google the issue with "TSB" at the end.

 

[ahtoxa11]

TLDR update: dealer drove it for a good bit at the speed I stated and didn't hear anything abnormal. I'm quite sure it's resonance because I'm hearing some from the exhaust as well in specific gear and at specific RPM/load. It sounds like exhaust drone.

I'm pretty sensitive to changes in vehicle sounds/feel, and I'm sure most people would never notice.

How about change the rear fluid and see if any heavy metal particles is in the oil? It only 3 quarts ($40-$50) and only takes a half hour, it just like draining the engine oil. I did mine at 15k miles and it was extremely dark, typical paste on the magnet.

I will be doing the diff service tomorrow - front and rear as I'm also replacing the front diff needle bearings with the ECGS bushing. I definitely have that groan/vibe that goes away when I put it into 4low.

You said your odometer is around 27k. Did you grease the drive (propeller) shafts at 15k?

Yep, I do them every 5k miles. Without that, I used to get that 'bump from behind' sensation when taking off from stop in colder weather. Been fine since I've been greasing it.

I have this exact issue on my 2019 4runner 2WD. The dealer replaced the rear differential and it made absolutely no difference.

I remember reading your post on this, actually, when I was researching. I'm chalking it up to how this vehicle is and the fact that I either haven't noticed it before or noticed it more after the skid install.

 

[BlackCloud]

Same thing happened to me w/ my '05 Outback. The bearings had gone bad.

 

[Jemplyr77]

I’m really leaning to this having something to do with the prop shaft harmonics or similar.

 

[raab02]

This thread and the TSB are why I finally committed to sound-deadening the back half of my truck.

My '18 with 55k had a little whine even after a fluid change and prop-shaft greasing. But mine happens when I let off the throttle and is fairly noticeable.

I'll get around to posting pictures if folks want but I ended up using butyl rubber and closed-cell foam over a lot of the rear floor and wheel wells. Very happy with the results. I no longer hear the whine and tire noise is significantly reduced. A Saturday well spent.

 

[T4RT]

I have a low audible whine which I just started noticing at higher speeds on slip stream paved sections of interstate at constant high speed. I hope it is just the fact my tires are warn and need to be replaced. After I went though a drive shaft failure shortly after purchasing my 4runner used (TSB Saved the day on the replacement) I have been very attentive to greasing the drive shaft with each oil change. Diff oil levels are correct as I did the change myself 20K ago. Maybe what I am hearing is what you guys are talking about. Guess I need to change these tires and see if things quiet down.

 

[SurferUK]

I noticed this on mine the other day, cruising on a very light throttle at about 60mph. It's not overly loud, I think anyone who is not interested in vehicles/mechanics wouldn't even notice it.

Seems like it's nothing to worry about if the TSB fix is sound deadening. I will turn the radio up.

Cheers everyone who posted on this thread.

 

[BlakeA]

I posted earlier about the dealer replacing the differential and it making absolutely no difference in the whine. I have since put on a Gobi rack which makes enough noise to partially mask the differential whine. LOL