4wd noise

[bassman29]

Hello
I have 2017 4runner 85K , long story short; the dealer changed out my transfer case fluid during the summer. I noticed a small leak in the fall coming from the aluminum crush washer. The dealer fixed the issue; I normally don't drive a lot in 4x4 except on the beach at low speeds and when it is snowing badly. The other day I was driving in 4wd and the noise was much louder than 2wd. Not sure if this is normal at higher speeds, around 30-40 mph. It does sound more like a loud humming noise. I usually don't drive this fast in 4wd, so I am unsure if this is just normal noise.

Thx
Bassman

 

[mc813]

Can't say I've ever noticed a difference in sound when using 4hi vs 2wd. Did the dealer check the fluid and replace any that might've leaked out?

 

[bassman29]

Can't say I've ever noticed a difference in sound when using 4hi vs 2wd. Did the dealer check the fluid and replace any that might've leaked out?

The bottom drain plug was leaking, so I assume they had to take the bolt out, replace the washer and drain, and fill the transfer case.

Thx

 

[Bmnorm2]

Or they just torqued the drain plug a little more and called it a day…. Remove the fill plug and check if it’s full.

 

[Lexington]

When switching from 2H to 4H I don’t hear any difference but when I’m in 4L the gears do make a slightly louder and windy gear noise.

 

[Bmnorm2]

When switching from 2H to 4H I don’t hear any difference but when I’m in 4L the gears do make a slightly louder and windy gear noise.

Good point, Lexington. OP, is the sound difference in 4H or 4L? It’s normal for 4L to be audibly different. You are changing from 1:1 to 2.28:1 gear ratio in the transfer case. So, the gear speed is 2.28x faster at the same road speed assuming the same transmission gear.

I would still confirm the transfer case is full after your leak and dealer visit.

 

[Lexington]

Right that’s what I always assumed the noise was coming from. Switching between 2H & 4H you’re not really changing gear speed but when you go to 4L, well now your gears are spinning at a much faster rate for the same speed which produces that slightly louder, higher windy pitch noise.

 

[DAW89446]

The OP stated that he was hearing the noise at 30-40 miles per hour. Unlikely he was in 4Lo. If he was, then the noise was his engine screaming at high RPM.

 

[Lexington]

The OP stated that he was hearing the noise at 30-40 miles per hour. Unlikely he was in 4Lo. If he was, then the noise was his engine screaming at high RPM.

Yes very true.

Bassman, for clarification when you were in 4WD were you in 4H or 4L?

 

[bassman29]

Yes very true.

Bassman, for clarification when you were in 4WD were you in 4H or 4L?

Hello
Sorry for the delay for some reason I am not getting notified, I was in 4H, I also was doing this when it was raining conditions just to ensure everything was working. Not sure if was just binding I normally drive with 4h at low speeds on the beach or when we get a lot of snow. But this year no real snow to drive in 4h.

thx

 

[Gclark949]

Does your paperwork say what fluid they used? OMM specifies SAE 75W