Warmed Transfer Case Sounds Just Like P/S When Cold, Why?

[Les Summer]

After long drives my transfer case, after it has fully warmed up, and only during stops, has a sound similar to that of a P/S pump when it’s really cold. I’m at 275k miles and I’ve been on top of my oil changes for the front and rear diff and transfer case. The noise is only there when I’m pulling into a parking lot after driving and it goes away on its own. Truck drives and shifts fine. The noise is not relevant during normal driving, it’s just I notice it during stops. I can’t say if it’s always been there and I’m just starting to notice it now. It sounds like normal truck noise but could be a foreshadowing to a problem. thoughts or comments appreciated.

 

[Trunk Monkey]

t-case noise is normal when cold, forum sees a handful of threads every winter with the same question

 

[Les Summer]

t-case noise is normal when cold, forum sees a handful of threads every winter with the same question

I thought the way I worded it would make it sound like I meant it was cold, but it's not cold. It's after driving it for a while, when at stops, it makes a sound that is identical to a P/S pump when it's cold, just not as loud, and comes and goes, but is not heard while driving at any speed.

 

[2001LC]

Could be gear lube you're using or level.

In addition; Could be a clogged breather, or its line:
In the 98-02 we're seeing breather line clogged with fluid. This line runs from a Y, that Automatic Transmission (A/T) and Transfer Case (T/C) breather lines connect to before going up to a single breather valve. All oils and gear lubes foam, so they have anti foaming agents added in. If a fluid become contaminated, or even sometimes just mixing fluids may dilute foaming agent. Just as overfilled result in excess fluid level, so does excessive foaming. Breather lines, may then become clogged. Since the breather lines are Y together. We're, then getting cross contamination between A/T and TC, when level gets to high.

Note: Toyota redesigned, so that each A/T and T/C have their own breather valve. They are no longer cross connected.

What I've seen in these clogged, excessive foaming and or overfilled cases. Is seals leaking.
I clear breather line and flush fluids.


BTW: Vane pumps (PS pump) don't whine much if at all when cold. Unless, Power Steering fluid used in them.
I use:
Mobil 1 MV ATF in Power Steering.
Mobil 1 MV ATF in 98-02 A/T.
Mobil 1 75W-90 LS gear lube in 98-07, T/C & diff's.

 

[nissanh]

The P/S whine is related to pressure/fluid. T-case has splash lubrication. Check the quality of fluid and inspect the magnet. Redline is an awesome gear oil and is abou $20 a liter but it works amazingly. If you willing to try it, give a try as the t-case takes about 1.5 L. I use Redline oil in my 92 Prizm/corolla manual transmission and even at 293K miles, gears shift like my brand new taco manual with 6K miles. It makes a real night and day difference.

 

[Les Summer]

Could be gear lube you're using or level.

In addition; Could be a clogged breather, or its line:
In the 98-02 we're seeing breather line clogged with fluid. This line runs from a Y, that Automatic Transmission (A/T) and Transfer Case (T/C) breather lines connect to before going up to a single breather valve. All oils and gear lubes foam, so they have anti foaming agents added in. If a fluid become contaminated, or even sometimes just mixing fluids may dilute foaming agent. Just as overfilled result in excess fluid level, so does excessive foaming. Breather lines, may then become clogged. Since the breather lines are Y together. We're, then getting cross contamination between A/T and TC, when level gets to high.

Note: Toyota redesigned, so that each A/T and T/C have their own breather valve. They are no longer cross connected.

What I've seen in these clogged, excessive foaming and or overfilled cases. Is seals leaking.
I clear breather line and flush fluids.


BTW: Vane pumps (PS pump) don't whine much if at all when cold. Unless, Power Steering fluid used in them.
I use:
Mobil 1 MV ATF in Power Steering.
Mobil 1 MV ATF in 98-02 A/T.
Mobil 1 75W-90 LS gear lube in 98-07, T/C & diff's.

I use liquimoly . Not overfilled, but I’m intrigued. How do I flush the breather lines to de-clog if possible without dropping all the fluid? Thank you for the excellent reply.

 

[Les Summer]

the transfer case breather is on the front "half" of the split case. it's on top on the left-hand side. Circled in red in the picture below.
View attachment 414213

@2001LC Is this what you’re talking about?
Although, I don’t think this is a transfer case for 100 Land Cruiser, but it’s the same concept, right?

 

[2001LC]

I use liquimoly . Not overfilled, but I’m intrigued. How do I flush the breather lines to de-clog if possible without dropping all the fluid? Thank you for the excellent reply.




View attachment 3597194

Again I'll state: When breather clogged we usually see leaks. This is due to pressure build-up in case.

I've had more than one say. "Didn't overfill" TC , yet I find it is. Two reasons for this. 1) Vehicle not level, while topping. 2) Fluid overfilled and or foamed in A/T and blew into TC via breather. This on the 98-02. Neither TC or A/T can be overfilled or contaminated.

You'll not loose any of the A/T, TC or differential fluids/lubes, checking or removing any of breathers. A/T - TC 98-02 breather valve, is front top of bell housing/engine area. The a long hose goes from valve, back to Y fitting on TC adapter case on LH side. I detach long hose from front the Y, and let hang down to ground into catch cup. Come back hours later, and check catch cup for fluid. Then blow through hose, to make sure unrestricted air flow out breather valve.

 

[Les Summer]

Again I'll state: When breather clogged we usually see leaks. This is due to pressure build-up in case.

I've had more than one say. "Didn't overfill" TC , yet I find it is. Two reasons for this. 1) Vehicle not level, while topping. 2) Fluid overfilled and or foamed in A/T and blew into TC via breather. This on the 98-02. Neither TC or A/T can be overfilled or contaminated.

You'll not loose any of the A/T, TC or differential fluids/lubes, checking or removing any of breathers. A/T - TC 98-02 breather valve, is front top of bell housing/engine area. The a long hose goes from valve, back to Y fitting on TC adapter case on LH side. I detach long hose from front the Y, and let hang down to ground into catch cup. Come back hours later, and check catch cup for fluid. Then blow through hose, to make sure unrestricted air flow out breather valve.

Even though I’m a little under the weather today, I just had to see it right, so I went down and I changed out the transfer case oil
I put in a quart and a half approximately and if anything I would say I was a little bit low because I don’t think that much came out

this time I got out the straight edge and the level to make sure the vehicle was perfectly level and I think I got pretty close to exact level

I just filled up the case with oil until it started coming out. I would say I was in the neighborhood of approximately one and 1/3 to one and a half quarts. Noise is slightly subsided.

I also made Sure the trans fluid level was exactly right, and found I was over less than 1/4 of a quart. If I mess with the breathers, I'm probably just going to install an ARB kit for the front and rear diff, trans and transfer case and be done with it. I think I'm heading in the direction of converting this truck to an all out overland machine. It's just so much fun to do, and it's what it was born to do. Thank you again for the expert help. Upgraded to the Silver Star.

 

[2001LC]

When draining, helps to catch some in a glass for inspection.

To top:
Top TC & Diff's, until gear lube runs out. Wait 15 minutes and top again. Best, drained when hot!

Top 2000 A/T fluid at ~160F. After shifting slowly, though all gears. Check while engine idling, A/T in P or N. Very unlikely you hit near 156F, unless you really loaded transmission in all forward gear. A good transmission with good fluid, takes a lot of time loading it, to get to 160F. Bad A/T and or bad fluid, temp jumps up fast. So 1/4 over on stick. May have been closer the 1/2 or even 1 qt. over.

I would encourage you. Go back out to shop, and pull long breather hose off the Y. Just let it hang to shop floor until tomorrow. It take 2 minutes and is easier then pulling drain plug.

 

[Les Summer]

When draining, helps to catch some in a glass for inspection.

To top:
Top TC & Diff's, until gear lube runs out. Wait 15 minutes and top again. Best, drained when hot!

Top 2000 A/T fluid at ~160F. After shifting slowly, though all gears. Check while engine idling, A/T in P or N. Very unlikely you hit near 156F, unless you really loaded transmission in all forward gear. A good transmission with good fluid, takes a lot of time loading it, to get to 160F. Bad A/T and or bad fluid, temp jumps up fast. So 1/4 over on stick. May have been closer the 1/2 or even 1 qt. over.

I would encourage you. Go back out to shop, and pull long breather hose off the Y. Just let it hang to shop floor until tomorrow. It take 2 minutes and is easier then pulling drain plug.

I have a hose and a pump i use. The skinny hose fits down through the A/T dipstick, I have achieved totally replacing my transmission fluid with this method slowly but surely, and not all at once, but over a period of time. The previous owner stripped out the transmission pan bolt , so once I got it back in there I don’t ever plan on removing it again unless I’m replacing the pan.

 

[Les Summer]

Dipstick immediately after 25 mile drive

 

[2001LC]

Most pan bolts, it's only the plug that has damaged threads. Unless some tried oversizing. Pan capture nut metal is harder than drian plug. I chase threads of pan and replace with new OEM drain plugs.

If you must. use dip suction tube. Suck all from pan (~3qt). Add back what was removed (~ 3qt) + 1/2qt, assuming was at high mark/160F. Then flush from cooler return line, the next ~9 qt. Leaving 1/2qt low, until final topping.

The wet line on dip stick shows; way way way overfilled. 2 to 3qts.
You must have proper temp (~160F), must shift through all gears slowly. Must have engine idling and A/T in P or N. Remove dip stick, wipe dry, reinsert dipstick all the ways to seat and remove to check level. Must hold stick with notched (measure) end down at all times.

If this actual level your way over filled. I also see what may be bubbles in fluid, near me red arrow. That would not be a good sign.

 

[Les Summer]

Most pan bolts, it's only the plug that has damaged threads. Unless some tried oversizing. Pan capture nut metal is harder than drian plug. I chase threads of pan and replace with new OEM drain plugs.

If you must. use dip suction tube. Suck all from pan (~3qt). Add back what was removed (~ 3qt) + 1/2qt, assuming was at high mark/160F. Then flush from cooler return line, the next ~9 qt. Leaving 1/2qt low, until final topping.

The wet line on dip stick shows; way way way overfilled. 2 to 3qts.
You must have proper temp (~160F), must shift through all gears slowly. Must have engine idling and A/T in P or N. Remove dip stick, wipe dry, reinsert dipstick all the ways to seat and remove to check level. Must hold stick with notched (measure) end down at all times.

If this actual level your way over filled. I also see what may be bubbles in fluid, near me red arrow. That would not be a good sign.
View attachment 3597997

I do remember purchasing a new pan bolt from the dealer and I won’t be soon e forgetting the $60 in Uber rides spent getting there that day!
The bolt went in really tight and I will never be removing that bolt again and chance getting stuck.

That said, I am at full operating temperature when I do these readings, I will however do another check keeping the tip down and I will update here.

You are going to have to explain stray fluid to me because I just removed a quart of transmission fluid and there is now consistently the appearance of low transmission fluid on one side of the stick, which is indicated by a straight line across at the low mark while I’m at full operating temperature , and higher up on the dipstick really no fluid, but on the other side of the stick I have stray fluid that creeps way past the full mark

I have never added anything more to this transmission than I’ve taken out ,I’m not willy-nilly with my measurements , so unless the previous owner had it overfilled, I’ve always put into the transmission exactly what I’ve taken out
I’ve now added that qt. back and once again on the back of the stick, I have a straight line at the correct mark , Yet on the flipside of the stick, I have stray transmission fluid creeping up the stick
I’m not getting any hard shifting, which would be indicative of an overfilled transmission, but I did notice after I took out a quart, while I wasn’t feeling slipping, I could feel the difference in the shifting and it was not as smooth
The first photo with the white mark on the stick, indicates the straight line across (hard to see from photo) after I removed 1 quart of fluid
the second picture it was taken from a YouTuber who demonstrates measuring transmission fluid on this exact vehicle and his transmission fluid appears to creep up the stick too, while he confesses that his transmission fluid level is perfectly at the full mark at full operating temperature. he even has a meter in his truck to gauge the trans fluid temp.

I added my own video. The sound is pretty isolated. You can gauge how loud the vehicle noise is being picked as compared to how loud my voice is in the video if that makes sense. The noise isn't always there, and not there at all during driving. I revved the engine a couple times to try to get the noise to pronounce itself.
Thanks again for all the advise. Please excuse my replies on this thread, they are crude. I've been doing most of this typing on my phone, while at work, and while actively working on the LC100 in my garage, a garage which has no power. I often edit my own posts when I re-read them and realize they are confusing or don't make sense.
Sound directly relates to turning the heat on and off from off to low. When I turn heat off that slight moaning sound goes away. just learned that.

 

[2001LC]

"The bolt went in really tight and I will never be removing that bolt again and chance getting stuck."
They key to replacing bolts or nuts, drain plug or others. Is cleaning threads of capture nut or bolt. Very often some old thread material/metal is left behind. Run in a new bolt, without cleaning old material out. You jam, possible damage threads of one or both.
I use a Thread Chase kit, which parts stores loan out:

Transfer case shifter do vibrate, more so in 98-02. Perfectly normal.

I also hear a low level whine. This is very likely the Automatic Transmission. I'd, do a full 12 qt flush, with Mobil 1 MV full synthetic ATF. Not a drain and fills. Adding back what comes out. Only works if you know level correct, before you begin.

If shifting is smooth, then don't worry.

BTW: The OM states: Check A/T level at operating temp. The FSM gives the actually A/T temp, which is 158f to 176F. When using a full synthetic like Mobil 1, it's very difficult to get up to even 158F on a 25 minute drive. I sit in shop, with foot on brake. I then load transmission, shift through gears pausing in each gear as I raise RPM to about 1,400 PRM. I never loan transmission in reverse, only forward gears. When I reach target A/T fluid temp. I shift to park and check level.

I use tech stream to see A/T temp. It's also possible to shoot pan with IR gun. Get gun within 3", of center of pan. It reads with ~-3 to -5f degrees of actual fluid temp.
This was after driving about 1 hour, HWY and then up hill (mtn road).

 

[Les Summer]

"The bolt went in really tight and I will never be removing that bolt again and chance getting stuck."
They key to replacing bolts or nuts, drain plug or others. Is cleaning threads of capture nut or bolt. Very often some old thread material/metal is left behind. Run in a new bolt, without cleaning old material out. You jam, possible damage threads of one or both.
I use a Thread Chase kit, which parts stores loan out:
View attachment 3599116
View attachment 3599117

Transfer case shifter do vibrate, more so in 98-02. Perfectly normal.

I also hear a low level whine. This is very likely the Automatic Transmission. I'd, do a full 12 qt flush, with Mobil 1 MV full synthetic ATF. Not a drain and fills. Adding back what comes out. Only works if you know level correct, before you begin.

If shifting is smooth, then don't worry.

BTW: The OM states: Check A/T level at operating temp. The FSM gives the actually A/T temp, which is 158f to 176F. When using a full synthetic like Mobil 1, it's very difficult to get up to even 158F on a 25 minute drive. I sit in shop, with foot on brake. I then load transmission, shift through gears pausing in each gear as I raise RPM to about 1,400 PRM. I never loan transmission in reverse, only forward gears. When I reach target A/T fluid temp. I shift to park and check level.

I use tech stream to see A/T temp. It's also possible to shoot pan with IR gun. Get gun within 3", of center of pan. It reads with ~-3 to -5f degrees of actual fluid temp.
This was after driving about 1 hour, HWY and then up hill (mtn road).
View attachment 3599143

Ah yes, well let me start with telling you there was good old helicoil in the pan when the old bolt dropped out, along with some of the helicoil, after a couple turns, and that was the first time I ever removed it since buying the truck used. The second time I removed the trans pan bolt was the last time, since the boogering had already been started by the previous owner or his/her mechanic. Once I got home from the Toyota dealer with my new pan bolt in hand, I had no interest in even trying to fix the pan threads, although I do have a kit that does that, not as nice as the nice Craftsman you have, but still I own one. I was tired and disgusted after spending 60 dollars on Uber rides to the dealer to un-strand my main and only vehicle, which I work on at a garage I rent in the city, that is nowhere near where I actually live, and with having to go to work the next day and it getting late, I turned the new sumbidch in, dumped in my 3 or so quarts of trans fluid (Toyota brand), and Called it a day.

As for a transmission flush, I have heard more than a few old wives tales of that destroying transmissions. Story usually goes the pressure that is built up in the system during the flush actually cleans the system too good, causing the clutch packs to loose the "gunk" that helps with pressurization for the thin steel or friction disks to squeeze together, resulting in a slipping transmission. I won't chance it. There has to be another way to know the absolute accuracy of how much transmission fluid is in the vehicle. I'd go for it if it was a newer vehicle, but not this one.

I drove about 200 miles to Pennsylvania today, and the truck is running great. I do hear that little whine at stops, but it subsides. I think I'm going to live with it. I really want my LC100 to be the 500k one that makes it on the OG engine and tranny with no major replacements having to be done. I know it takes meticulous maintenance to get it there. I'm really going to try for that.

 

[2001LC]

Your fluid looks clean. Certainly not 250K miles fluid. Do you know what all DOTs, brand, types have be added! Very few do!

I understand your reluctance to repair or replace pan. Which with your dipstick tube sucking pump, you don't need a drain plug anyway.
No doubt you've already, read in mud. The 2000 is the one, with a weak/failing A/T. But the few that have failed, reportedly have done so, long before 250K miles. You may even have a replacement A/T.

Personally I have no fear of flushing A/T:

First if A/T fails after a full flush, it's a bad transmission. Better fail near home base, than 500 miles from nowhere! But I've yet to see a failure after a flush.

I've done more full flushes 100 & 200 series, than I care to remember. In LC/LX, up to 400K miles on the clock. In each case, where there was: Shifting, Sound and or high ATF Temp issues. Full flushing's with full synthetic ATF, has only improved conditions. I've cured many 100 series A/T, other shops said replace it.

I do a no pressure induced flush. I simply use, A/T own pump to pump out fluid as I pour in new.

Why do a full 12qt flush. A few reasons:
1) We've no idea in most cases, what fluid or contaminate may have been added/induced into A/T.
2) Fluid gets old. Fresh fluid will reduce fluid operating temp, help clean and keep A/T clean. This is especially true, when a full synthetic ATF used.

My favorite ATF is: Mobil 1 MV ATF. Which I use in all Power Steering (100 & 200 series) and 98-02 100 series A/T.
My second favorite is: Mobil MV ATF full synthetic. Which I now use in 2003-up.
I'd use Mobil 1, in all. But Mobil 1 will not rate it for Toyota IV (2003 only) or Toyota WS (2004-up).

BTW: Never use Power Steering fluid in Land Cruiser/LX. Which Vane pump will hum if used. Also, steering will likely be stiff on cold mornings.

A few issues to address, if you've not already:

Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert!

TICK TICK TICK POP POP POP is a ticking time bomb, often mistaken as exhaust manifold crack or gasket leak leak. ALERT, ALERT, ALERT: Spark plugs are working themselves loose. "Walking Out" Then blowing out of head, taking their female threads of head with them! Very damaging! You think TICK...

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Radiator fins need cleaning! Alert Alert Alert

I've a 06LC w/192K I just bought. In reading history I found PO complained of engine temp raising when both front and rear AC on. Toyota Dealership diagnosed with clogged radiator fins. Recommended new OEM radiator, $600 for the US spec Radaitor plus coolant and labor. They should have added...

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Steering Flush & Cleaning

Cleaning power steering reservoir and flushing it's fluid. Keeps Vane pump and rack & pinion in top condition. These step will help you get, a better idea on how to. Power wash reservoir & hoses using a degreaser, before starting service. Makes for cleaner job. Repeat, once all done with...

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[Les Summer]

Your fluid looks clean. Certainly not 250K miles fluid. Do you know what all DOTs, brand, types have be added! Very few do!

I understand your reluctance to repair or replace pan. Which with your dipstick tube sucking pump, you don't need a drain plug anyway.
No doubt you've already, read in mud. The 2000 is the one, with a weak/failing A/T. But the few that have failed, reportedly have done so, long before 250K miles. You may even have a replacement A/T.

Personally I have no fear of flushing A/T:

First if A/T fails after a full flush, it's a bad transmission. Better fail near home base, than 500 miles from nowhere! But I've yet to see a failure after a flush.

I've done more full flushes 100 & 200 series, than I care to remember. In LC/LX, up to 400K miles on the clock. In each case, where there was: Shifting, Sound and or high ATF Temp issues. Full flushing's with full synthetic ATF, has only improved conditions. I've cured many 100 series A/T, other shops said replace it.

I do a no pressure induced flush. I simply use, A/T own pump to pump out fluid as I pour in new.

Why do a full 12qt flush. A few reasons:
1) We've no idea in most cases, what fluid or contaminate may have been added/induced into A/T.
2) Fluid gets old. Fresh fluid will reduce fluid operating temp, help clean and keep A/T clean. This is especially true, when a full synthetic ATF used.

My favorite ATF is: Mobil 1 MV ATF. Which I use in all Power Steering (100 & 200 series) and 98-02 100 series A/T.
My second favorite is: Mobil MV ATF full synthetic. Which I now use in 2003-up.
I'd use Mobil 1, in all. But Mobil 1 will not rate it for Toyota IV (2003 only) or Toyota WS (2004-up).

BTW: Never use Power Steering fluid in Land Cruiser/LX. Which Vane pump will hum if used. Also, steering will likely be stiff on cold mornings.

A few issues to address, if you've not already:

Ticking time bomb TICK TICK TICK: Spark plugs Alert Alert Alert!

TICK TICK TICK POP POP POP is a ticking time bomb, often mistaken as exhaust manifold crack or gasket leak leak. ALERT, ALERT, ALERT: Spark plugs are working themselves loose. "Walking Out" Then blowing out of head, taking their female threads of head with them! Very damaging! You think TICK...

forum.ih8mud.com

Radiator fins need cleaning! Alert Alert Alert

I've a 06LC w/192K I just bought. In reading history I found PO complained of engine temp raising when both front and rear AC on. Toyota Dealership diagnosed with clogged radiator fins. Recommended new OEM radiator, $600 for the US spec Radaitor plus coolant and labor. They should have added...

forum.ih8mud.com

Steering Flush & Cleaning

Cleaning power steering reservoir and flushing it's fluid. Keeps Vane pump and rack & pinion in top condition. These step will help you get, a better idea on how to. Power wash reservoir & hoses using a degreaser, before starting service. Makes for cleaner job. Repeat, once all done with...

forum.ih8mud.com

I have been using Toyota brand ATF to replace whatever was in the transmission. I wonder if this mixing could be the culprit for my whine. Do you think the Mobil 1 MV ATF Full Synthetic is better than Toyota? I recently placed in Lucas ATF (1qt.) and it seemed to not do any harm, and shifts a bit smoother. I had the whine before the Lucas. The no pressure flush sounds interesting.

 

[2001LC]

I have been using Toyota brand ATF to replace whatever was in the transmission. I wonder if this mixing could be the culprit for my whine. Do you think the Mobil 1 MV ATF Full Synthetic is better than Toyota? I recently placed in Lucas ATF (1qt.) and it seemed to not do any harm, and shifts a bit smoother. I had the whine before the Lucas. The no pressure flush sounds interesting.

YES!. Both are Exxon/Mobil (see Toyota bottles). But Mobil 1, is top shelve and a full synthetic. Toyota Dealership use bulk, unless issue like with A/T running hot. Than they use Mobil 1, in A/T's calling for Dex II or III.

I'm always against mix oils, coolant, etc. Just to many different variation and additive package.

 

[Les Summer]

YES!. Both are Exxon/Mobil (see Toyota bottles). But Mobil 1, is top shelve and a full synthetic. Toyota Dealership use bulk, unless issue like with A/T running hot. Than they use Mobil 1, in A/T's calling for Dex II or III.

I'm always against mix oils, coolant, etc. Just to many different variation and additive package.

I will definitely be giving the Mobil 1 a try. I am going to for preventive maintenance replace my rear axle breather hose with OEM, and I'm having a helluva time finding any part numbers for the T case , front diff, and trans breathers. I'd like to change them out for good measure. Pictured the ATF MV you recommend.

here is the breather hose assy for the rear axle for the 2000 Land Cruiser:
Part No.: 42306-60140