10-20 MPH Gear Whirring Noise

[yuji]

I have some noises I want to share.. It's pretty quiet (LX470 is pretty damn sound deadened though) and nothing that screams "get towed now!!" but I am thinking about it.

From 10-20MPH, I can hear a light gear meshing noise coming from the front (like my friend's Subaru made 100% of the time). Can't hear it above 20MPH likely because the outside noises are too loud or the pitch gets too high. I can't hear it if there's cars nearby.

Noise happens with or without the pedal. Downhill, uphill. Neutral. Sometimes, it's non linear sounds; instead of: "whiiiiiiiiiiir", it's "whiiir whir whir whiiiir" even though I'm going the same speed. I typically notice it when I let OFF the gas when it's completely quiet otherwise.

I also get a turbo-like sound accelerating (and only accelerating) which reminds me of the recent "drivetrain whine" thread where the front diff didn't have oil. I wonder if the temperature has anything to do with this.. It's been cold these days.

Are the two sounds related?

Acceleration == different, high pitched sound, rolling at all @10-20MPH = gears.. kind of like rolling an RC car along the ground with your hand. Low speed gear meshing noise.

I'm buying all tranny fluid / diff fluid / tcase fluid and doing a flush due to my fears about this as well as peace of mind knowing I did the fluids at exactly this date.

If only the weather would be better... ahhhh!

 

[GaFJC]

The turbo-like sound accelerating, if it happens when its cold outside, could be the transfer case warming up. It's typical of 100's in cold weather. Cold temps can vary, mine has done it even in the mid to upper 40's.

Mine actually got worse when I replaced the dino gear lube with Amsoil fully syn.

 

[Keowee]

Same noise with mine when the temps drop near 40 or lower. Lasts a few seconds and stops. I was thinking transfer case as well.

 

[yuji]

The turbo-like sound accelerating, if it happens when its cold outside, could be the transfer case warming up. It's typical of 100's in cold weather. Cold temps can vary, mine has done it even in the mid to upper 40's.

Mine actually got worse when I replaced the dino gear lube with Amsoil fully syn.

I need more sample data to figure out patterns, but it seems that the whirring gear noise goes away once warmed up. It sounds like meshing gears (very slow, very quiet).

As for the supercharger kinda noise while accelerating, that's still there.

 

[yuji]

Same noise with mine when the temps drop near 40 or lower. Lasts a few seconds and stops. I was thinking transfer case as well.

Hey thanks for the comment! I noticed today that I couldn't hear it on the way home... meaning once vehicle was warmed up, I couldn't hear the gear noise. I will see if it appears in the morning like clockwork, then goes away after warmup.


Supercharger noise is still interesting though; only when under forward load.

 

[2000UZJ]

The gear whine is normal from the t-case when the fluids are cold. The colder the outside temperature is outside the louder the gear whine will be. Nothing to be concerned about unless there is a noticeable vibration. The "boost" sound is a possible bearing that whines or makes a sound when cold. I have possibly the loudest "boost" sound, I have never figured out what it is, but it makes a racket at all times. (the static in the first split second is me turning the radio off). It's very audible outside when passing by as well, makes for a fun tunnel passes. This video was taken with the windows up.

 

[yuji]

The gear whine is normal from the t-case when the fluids are cold. The colder the outside temperature is outside the louder the gear whine will be. Nothing to be concerned about unless there is a noticeable vibration. The "boost" sound is a possible bearing that whines or makes a sound when cold. I have possibly the loudest "boost" sound, I have never figured out what it is, but it makes a racket at all times. (the static in the first split second is me turning the radio off). It's very audible outside when passing by as well, makes for a fun tunnel passes. This video was taken with the windows up.

First of all, thanks for the T-Case information. I won't even flinch about it now. Yes it is the first time it's cold and I've owned the truck.

Ah ha!! Thank you for sharing this video. This is exactly the noise I've had since purchase. I tried to record it, but the iPhone would not pick up the subtle high pitch. So yours must be much much louder than mine!

Almost got an audio friend with super mics to help me out to show you guys.

How long have you had this boost noise?

 

[2000UZJ]

First of all, thanks for the T-Case information. I won't even flinch about it now. Yes it is the first time it's cold and I've owned the truck.

Ah ha!! Thank you for sharing this video. This is exactly the noise I've had since purchase. I tried to record it, but the iPhone would not pick up the subtle high pitch. So yours must be much much louder than mine!

Almost got an audio friend with super mics to help me out to show you guys.

How long have you had this boost noise?

I've had my stereo checked multiple times for feed back or interference, none found. It's coming from one of the pumps. It may be the alternator but unsure. I've had the boost sound for roughly 2 years with no ill effects. It's RPM related, so something on the belt. My boost sound is very audible, almost turbo loud. Fun to mess with people though, sounds like its MUCH faster

 

[yuji]

I've had my stereo checked multiple times for feed back or interference, none found. It's coming from one of the pumps. It may be the alternator but unsure. I've had the boost sound for roughly 2 years with no ill effects. It's RPM related, so something on the belt. My boost sound is very audible, almost turbo loud. Fun to mess with people though, sounds like its MUCH faster

Hahaha, yeah! It definitely sounds like something about to take off

Well that's good to hear it's nothing to worry about really... I only started wondering about it due to the recent front diff thread. Next time I get the truck on stands I'll listen for where the noise is coming from.

 

[2000UZJ]

Hahaha, yeah! It definitely sounds like something about to take off

Well that's good to hear it's nothing to worry about really... I only started wondering about it due to the recent front diff thread. Next time I get the truck on stands I'll listen for where the noise is coming from.

FYI, mine only does it under load which makes me assume it's driveline/pumps. That would be a easy test to check to see if yours is electrical or mechanical. I wouldn't write it off as a "not to worry sound" until you can confirm all causes if the whine. Have you tried putting the truck in neutral and going through the RPM band listening for it? If you hear the whine clearly inside windows up I would say electrical. Have a friend drive it up and down the street in each gear and listen for it outside. That's how I figured out mine was mechanical.

 

[Nottajeep]

The turbo-like sound accelerating, if it happens when its cold outside, could be the transfer case warming up. It's typical of 100's in cold weather. Cold temps can vary, mine has done it even in the mid to upper 40's.

Mine actually got worse when I replaced the dino gear lube with Amsoil fully syn.

The Mobil 1 diff oil eliminated my gear whine on cold days. That stuff has been really smooth and quite on the drive train

Sent from my droid

 

[yuji]

FYI, mine only does it under load which makes me assume it's driveline/pumps. That would be a easy test to check to see if yours is electrical or mechanical. I wouldn't write it off as a "not to worry sound" until you can confirm all causes if the whine. Have you tried putting the truck in neutral and going through the RPM band listening for it? If you hear the whine clearly inside windows up I would say electrical. Have a friend drive it up and down the street in each gear and listen for it outside. That's how I figured out mine was mechanical.

Mine only happens under pretty heavy load at the exact timing with yours. I didn't even think it a problem till reading the diff thread, then I became a 100 series hypochondriac.

The symptoms match! I MUST HAVE ALL OF THE PROBLEMS!

I get no sounds in neutral and only hear it under heavy accelerator load. I used to notice it only when hauling ass up a hill.


How do you detect if it's electrical? Never would have thought that! Does electrical noise only under load make sense?

I'll do the friend trick but It's a pretty faint sound even from inside.