Center Diff Noise (1 Viewer)

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Joined
Nov 4, 2004
Threads
3
Messages
18
Location
Chandler, AZ
Hi, I'm a frequent lurker and first time poster...and I believe I have a problem. First some background info...

Bought an 97 LX450 about three weeks ago, factory lockers, very, very nice shape...looked to be a mall cruiser. It had about 81K miles.

Since that time, I have had a slight ping/rattle...it has been difficult to track down, but I believe that I have found it. Here's how I tracked it down:

1. Noticed that when cold, no ping/rattle.
2. Ping/rattle doesn't vary with engine rpm.
3. Ping/rattle still evident when coasting with engine off and transmission in neutral
4. Ping/rattle still evident when coasting with engine off, transmission in neutral and center diff in neutral
5. Sound can be heard in the cab and is localized to around the emergency brake lever (wife was driving when I localized the sound...didn't want to be taking my eyes off the road for that long :) ).

I was thinking it was something downstream of the center diff, but I believe that I have found the noise now. I disconnected both front and rear drive shafts (to isolate driveshaft/axles from the problem space). I repeated steps 2 through 4 above with the driveshafts disconnected and found that the noice was only evident when center diff was in "H" (I think the output shaft didn't get going fast enough in "L"). Note: The LX was on jackstands at several points to increase safety :D Next, I took my mechanics stethoscope :) and placed it on the transmission in various places (first rigging up the gas petal to go about 35 mph indicated). No pinging/rattling on the transmission (confirmation of what was heard in the cab). Next, I checked the center diff and noticed that the rattle/ping appears to be coming from the center diff :mad:

So I dove into the archives here and on birfield and it doesn't look like this happens very often. I think Cruiserdan only knows of 3 of these things that needed to be fixed. Has anybody else cracked open their center diff to replace a bearing or two? I've rebuilt a few Samurai transfer cases and a Samurai transmission so I have the press to do the work. For those that have done it, how involved is it? Any suggestions on taking it apart first and only purchasing the replacement bearing or should I do the entire thing?

Or, should I do nothing, put some synthetic gear oil in it and see if it quiets down or goes away (not my preferred solution, but if it "fixes" the problem it might be worth a try)?

Mike
 
Note: The LX was on jackstands at several points to increase safety Next, I took my mechanics stethoscope and placed it on the transmission in various places (first rigging up the gas petal to go about 35 mph indicated).

From the Darwin Awards:

[Kalamazoo Gazette]:
James Burns, 34, (a mechanic) of Alamo, MI, was killed in March as he was trying to repair what police describe as a "farm-type truck." Burns got a friend to drive the truck on a highway while Burns hung underneath so that he could ascertain the source of a troubling noise. Burns' clothes caught on something, however, and the other man found Burns "wrapped in the drive shaft."


Your story reminded me of the above story... I hope your vehicle was pointed towards something that could stop it.. Sure as s*** you can't run 35mph in your best physical condition and certainly not after being rolled over by a 6000 pound vehicle...

Why would you ever crawl under a vehicle with the engine running, in gear, the accelerator rigged and no partner to help you out in the event something did go wrong in the first place? Simply amazing...
 
I would look toward the output bearing on either the front or rear out put sections. I have found these bearings to go around 150k miles but not usually at your milage. Are you sure it is not a U-joint going bad from no grease. Any how the t-case is easy to remove and once on a bench it is easy to take apart. I would give yourself a couple of days to tear it down and repair it if you can find the parts you need in a speedy time frame. I do not know of many dealers that stock parts to rebuild the t-case.
I think if you had some one with you to regulate the throttle and went back under it to see where in the t-case the sound is, you might find the problem before you get into the t-case. better to have two doing this then one person. later robbie
 
First, Robbie, thanks for the reply...I did exactly that, but didn't need a partner since I rigged up something to press the accelerator (two foot long stick and the electric seat did the trick to press the pedal). :D I did check the u-joints when I disconnected the drive shafts and there was no play.

I appreciate the Darwin Award reference MrZumma (because I like humor :D ), but if you read my original email very carefully :doh: you will note that both the front and read drive shafts were disconnected (at the center diff point) when I performed my test (i.e., the only moving components at the time of test was the engine and the center diff flanges - in other words, the wheels were not rotating, the vehicle, should it have dropped, would not have gone anywhere). The vehicle was on 6 jack stands, two on each axle and two under the frame, and the hydraulic jack was positioned under the front differential for that extra margin of safety should all 6 jack stands fail and the vehicle fall the 1 inches plus to the ground. In addition, I pushed laterally and longitudinally on the vehicle once it was on the jack stands before I even started it...just to ensure that the vibration of the engine would not allow it to fall off the jack stands.

This entire procedure was performed WITHOUT THE DRIVESHAFTS CONNECTED to the Center Diff.

Sorry to waste this bandwidth...just didn't want you all to think that some dufus/nimrod/numbskull was attempting a quick entry into the Darwin Awards Hall of Fame.

Mike :cheers:
 
:doh: is right... My sincere apologies Mike...
 
So where in the t-case was the noise the loudest? no reason to shout, if you read your own statement you may find it to a bit confusing to some of us.
Play is one thing while a bit of ruffness is another. If the u-joint had any area where it was not smooth, then that is a problem. later robbie
 
Sorry, it was late last night when I wrote that up...sometimes I have a tendency to blabber on and on so it is I who should have been more clear.

I'll try to grab a picture of the spot on the housing from where the sound is the loudest. Stay tuned...

Thanks,
Mike
 
Here's the pic of the rear portion of the center diff. It was taken from the driver's side and I have annotated it.

I don't know why the sound is the loudest at the lowest point, but that's the way it seems...though I don't know if there is a bearing in that immediate area (need to download the FSM from techinfo.toyota.com site). I did check other parts of the center diff and the bearing noises appeared normal (including near the front flange as well as the main (upper portion) of the center diff housing).

Another question is: Does Toyota use red RTV from the factory or has this case been opened before?

If the noise is coming from the lower rear portion, can I just take that portion off and leave the rest of the diff on the vehicle (I know, I know, check the FSM, but thought I might ask here first while I work on the download of the FSM).

I appreciate all of your help.

Thanks,
Mike
DiffNoise_Small.jpg
 
mine also has the red rtv, so i am pretty sure it's factory. Nice picture. It always helps me identify when there are pics associated.
 
While you are getting the FSM get the new car features manual also it has some nice diagrams of the T-case

BTW that area is there the Viscous coupler lives, there is a bearing a few inches foreword and aft but none in that area

Does the noise go away if you lock the CDL? Do you have a CDL switch?
 
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I have learned so much from this site, but it simply amazes me the number of people that chime in with these stupid Darwin awards. The man went out of his way to post accurate information, simply looking for help, then poof, the stupid Darwin Award quote. I also visit the Yamaha Venture tech site, and you never see this type of ribbing. Those guys go out of their way to help you, here you have to weed through the wise cracks.
 
Thanks for the info RavenTai. I don't have a CDL yet, but I now have downloaded the full FSM (took about 4 to 5 hours...it wasn't pretty, but I have it now). I see the bearing you are talking about...I can only hope that it is the one in the Rear Extension Housing...it sure would make the whole adventure much less difficult...looks like I wouldn't even need to drop the entire center diff section.

I'll reply with what I find.

Mike
 
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put it in low that will lock the CDL. lockign the CDL keeps the Viscous coupler from turning internally, see if it goes away (straw grasp)
 
Fixed the problem...finally.

RavenTai, I don't have a CDL switch, so my only choice was to try it in low (to force the CDL lockup). Unfortunately, the noise only presented itself at higher speeds, so when it was in low I didn't hear it.

I used the FSM I downloaded and decided to drop the Rear Extension of the Center Diff. Once off the vehicle, I rotated the shaft in the rear extension housing and noticed some play and a slight grinding noise. After a trip to Harbor Freight to pick up some very long snap ring pliers, I was able to remove all of the snap rings to get to the bearing. Upon getting the bearing out, I spun it and it would intermittently catch (like one of the ball bearings was munched). I called around and was able to find a replacement bearing. Cleaned it all up, lubricated all of the pieces and put the rear extension housing back on. Pumped it full of Mobil 1 75W-90 and tested it out. Ahhh, the sweet sound of silence!

Thanks for the help,
Mike
 
Nice work :beer:
 

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