Center Diff Noise/Whine - Any experience here?

[Andres G]

Hello All,

I've come across a strange whine coming from my cruiser during the last really cold weather days here (Midwest). I am puzzled by it because I don't recall doing anything to the cruiser at all prior to it appearing that I could relate this sound to... it simply showed up the first snow day about two weeks ago.

What it sounds like:
A very faint, almost imperceptible high pitch whine. It is related to speed (not engine RPM). It cannot be heard if the HVAC fan is on...
It is definitely coming from center differential. Very present inside the cabin.

When does it show up:
Can only be heard at very low speeds, like 25mph or below.
It is not load related, as it is present under acceleration and coasting. I tried coasting down a hill with the transmission in neutral, and with the transfer box in neutral as well. Sound is present between 2 and 25 mph.
Tried connecting/disconnecting the center diff lock but nothing changed when I did this.

Other Conditions:
It happens when weather is at least 8/10 degrees Fahrenheit below freezing.
It is only present when first driving in the AM or after several hours of the car sitting outside (parking lot at work).
Goes away after a few minutes (4-6) of driving. Can't be heard after that.
Weather was in the 60's today, no sound was present when I left the garage.

Vehicle Specs:
1998 Land Cruiser 100
165000 Miles (I've had it for about 18 months & 10K miles)
3rd owner - Very good condition vehicle - Has Tow PKG

Thoughs & Questions:
The work I've done on the Cruiser during fall/early winter (about 2000 miles ago) was:
# Lubricate drive shafts
# Transmission drain & fill twice = 7 quarts - used Castrol correct spec.
# Transfer box oil change - Used Valvoline correct spec
# Did the work myself in my garage.

The only two things I can think of that could be causing this are:
a) If Transmission oil also lubricates center diff (I am pretty sure it doesn't), may I have used inadequate spec oil or insufficient quantity?
b) If Transfer box oil lubricates center diff (I thing it does), may I have used inadequate spec oil or insufficient quantity?

Has anyone gone thru something like this? Any suggestions on what to look into? Anyone consider this "normal" for mileage/age?

Your input will be welcome.

Thanks,
Andres

 

[NWForester]

The sound you are hearing I believe is just the normal sound gears make when the 90W is cold and viscous. Mine does this all the time. We get so used to the sounds (or lack thereof) thinner weight oils and helical cut gears produce that good old fashion gear noise at first appears problematic.

The trans does not lube the transfer case.

The center diff is part of the transfer case.

You didn't mention wether the noise remained after you had driven a while. Check and see if the noise remains at the conclusion of driving. It should go away as the gear oil picks up heat.

 

[Andres G]

Thanks for your response Richard.

I meant to explain that in fact, the noise went away after 4/6 minutes of driving. I assume this how long it takes for gear oil to start getting up to temp.

One question that comes up then is how do I ensure I filled the T-Case with enough oil?

Thanks again,
Andres G

 

[TriArcher]

Just pop off the diff fill plug. Fluid should be just about level with it.

 

[Scottb4857]

^^^
FSM for this is have the vehicle on level ground. Fill tcase with correct oil until it starts to come out of the fill hole. Put a new crush washer on the drain plug and don't overtorque when installing.

 

[TTO5]

Affirmative. They do that when cold. Run her and forget about it.

 

[bmwguy]

I am experiencing the same engine whine noise. I did the test with the radio and blower to see if its the alternator. it did not affect the noise level. I am going to assume it's the serpretine/drive belt tensioner. The 02 lexus has 117k miles and the TB and Waterpump and etc were replaced 7k miles ago.

I called around locally for 16620-0w101. The local Toy dealer wanted 94 dollars. Lexus dealer wanted 126.
The Toy Dealer mentioned that they are running a 20% discount on parts this weekend so it will bring it down to 75.00. Decent deal.