Transfer case noise?

[jgue467]

My 01 runner with about 243k miles recently scaled west texas peaks, then the sierra madre a couple times and finally the rockies. All went well except i noticed this sound coming from the transfer case sometime after the rockies. I used a stethescope to hone in on the noise, sounds like a tapping sound in video below.

It is most obvious when the vehicle is in gear, idling. If i give is just a small amount of fuel the noise goes away. I took it to my trusty mechanic of 30+ years, he said it was probably the transfer case chain had stretched but i shouldn't worry about it unless the noise gets too bothersome. The vehicle runs well otherwise. What does everyone think the problem is? What to do about it? thanks.


https://www.youtube.com/watch?v=R8bRph91yVI&feature=em-upload_owner

 

[jgue467]

Checked FSM, says 1 cause of transfer noise is low oil level. I did drain/fill it in may, is it possible i didn't fill completely? I'll check it again...

 

[jgue467]

BUMP! Please help me out!

Well I checked the fluid level, it is just fine and that oil was changed before my long haul 2 months ago. Noise (tapping sound in vid) is not always there, sometimes even in gear there is nothing, then other times even out of gear i can hear a faint tapping. Like i said using the scope, it is very easy to tell the noise comes from the transfer case and nothing else. More towards the front/center of the case and not much at all from the back.

I am also starting to notice one or more of the u-joints occassionally makes a mild squelch as it engages in reverse but not forward gears. Experts: Any relation to the two? I'm hoping to get some help on here otherwise this is probably beyond my capabilities and I'll have to submit to the ASE mechanic i trust. Thanks in advance!!

 

[Doc2012]

Not trying to contradict you, but this post makes NO sense at all to me, and, quie possibly, every one else here, since there have been no replys.

I've watched the vid, and have one question:

How on earth would your T-case be making a tapping noise when it's NOT moving?


That makes no sense to me. When you're not moving, your transfer case isn't moving. There should be NO reason at all for it to be making that tapping noise, while in PARK. Driving, I can see it. Park, no. Nothing is moving in there.


There's two things that I can think of, that can POSSIBLY be the cause of this "tap" are the following:

1) The chain is loose in there, and it tapping the side of the case when the motor is idling.

This seems to be the most feesable option. No tension on the chain, so it's just going with the vibes of the motor.



2) The mounting bracket ON THE TRANSMISSION is loose, {(4) 14mm bolts} and is causing the transmission to rock with the engine, thus causing the tapping.


I guess another option is that the t-case itself is loose from the t-case adapter.

I would check everything in there. Make sure the bolts are tight, and if it still persists, then look into another t-case.

 

[jgue467]

There's two things that I can think of, that can POSSIBLY be the cause of this "tap" are the following:

1) The chain is loose in there, and it tapping the side of the case when the motor is idling. Yeah, this is what my mechanic said, he didn't seem to be the least concerned about it and just said if the noise bothers me to stop by again. He said the climbs stretched the chain and like your're saying it now taps when idling.

This seems to be the most feesable option. No tension on the chain, so it's just going with the vibes of the motor.

2) The mounting bracket ON THE TRANSMISSION is loose, {(4) 14mm bolts} and is causing the transmission to rock with the engine, thus causing the tapping.


I guess another option is that the t-case itself is loose from the t-case adapter.

I would check everything in there. Make sure the bolts are tight, and if it still persists, then look into another t-case.

Hey Doc, I appreciate any response. I'm not super mechanical but can learn. I'm learning from you now, didn't really know how the tcase operates in detail other than its general purpose. What you say makes sense. All i know is i've had the unit about 65k (well maintained) miles w/out this 'new' sound that came about just about the time the rockys were crossed a few weeds ago. The vehicle operates Perfectly otherwise (starting/running/shift points/smoothness/fuel efficiency), but the noise is kinda annoying (if not embarrassing after awhile!) So I Really would like to get rid of it (properly) so again appreciate the response buddy.

As obvious as your suggestions seem in hindsight, it didn't occur to me to check for tightness overall, I'm hitting that little project next! I was hoping the reason for the lack of responses was either a bad vid or it's just not a common problem? I've searched the topic and don't find much that is actually relevant to what I'm hearing.

So if it turns out to be more like #1 (loose chain), what options do you think we have to repair that? In the meantime I'll scan the FSM for diagrams, tensioner maybe? I'm hoping nothing is going to 'blow up' or cause more damage while continuing to use it as is. thanks. :^)

 

[Doc2012]

Hey Doc, I appreciate any response. I'm not super mechanical but can learn. I'm learning from you now, didn't really know how the tcase operates in detail other than its general purpose. What you say makes sense. All i know is i've had the unit about 65k (well maintained) miles w/out this 'new' sound that came about just about the time the rockys were crossed a few weeds ago. The vehicle operates Perfectly otherwise (starting/running/shift points/smoothness/fuel efficiency), but the noise is kinda annoying (if not embarrassing after awhile!) So I Really would like to get rid of it (properly) so again appreciate the response buddy.

As obvious as your suggestions seem in hindsight, it didn't occur to me to check for tightness overall, I'm hitting that little project next! I was hoping the reason for the lack of responses was either a bad vid or it's just not a common problem? I've searched the topic and don't find much that is actually relevant to what I'm hearing.

So if it turns out to be more like #1 (loose chain), what options do you think we have to repair that? In the meantime I'll scan the FSM for diagrams, tensioner maybe? I'm hoping nothing is going to 'blow up' or cause more damage while continuing to use it as is. thanks. :^)

There really isn't anything you can do to tighten the chain.

There isn't a tensioner for the t-case chain.

You either have to replace it, or get a new transfer case.

If you can find someone to do it for you cheap, then I would go that route.

If not, you can get a T-case from a scrap yard.

ORRRR..You can get an Inch Worm Lefty. This is a second gen 4Runner case, with GEARS instead of a chain.

They were orginally left hand drop, but Inch Worm has remanufactured them to be Right hand drop, which is what our 4Runners are.

These are bennificial because they are GEAR driven, not chain driven. No chain to stretch. You can also choose to get a REDUCED low gear, which will help you when you're wheeling(if that's what you're doing). It changed the stock 2.28:1 ratio to a 4.7:1 ratio.


The Lefty also includes built in "clocking", allowing your transfer case to remain between the frame rails and not hang down.

They're awesome. BUT EXPENSIVE!!!

Seriously. Best t-case for a Toyota out there.....

 

[jgue467]

Update on my transfer case noise

Well guess what? I did nothing about the occasional tapping noise coming from the transfer case all fall and winter. Now the sound is virtually gone! I mean I'm happy for that but stumped as to why it appeared then disappeared.

All works as it should and no tapping noise in gear, idling or moving. I'll take it but don't understand what was going on. Thoughts?

 

[H20Camper]

My thoughts are your exhaust was rubbing lightly somewhere. I believe when you put it in gear with the brake applied the slight torqing of the engine may have moved it just far enouph to clang against something. I don't see any way that what was described could be a transfer case. The listen to the screw driver trick can pick up a noise a fair ways from the true culprit.