Topic: tcase noise

[dok33]

I've got a bearing type noise coming from the tcase/front end that's getting louder on my '87 4Runner (5spd, 4cyl). It's similar to the sound my tranny made about 3 months before I had to replace it.

It's faint in 2wd with the hubs locked, and pretty loud in 4wd, especially over 25mph. There's no noise when in 2wd with the hubs unlocked.  I originally thought it was a u-joint on my front driveshaft, but I replaced that and it's still there. I also noticed a faint noise when I put the tcase in 4wd without the front shaft hooked up, which is why I think it may be a bad bearing or something in the tcase.

Anyone have any insight on this? If it is the front tranny bearing, how easy is it to get to and replace?  Thanks!

[84runner]

What does it sound like when its cold? Does it get louder as the vehicle warms up?  This might narrow it down to a bearing .

[dok33 [OP]]

Thanks for the info, I'll try that out tomorrow, it's definitely cold enough here to do a good test!

[Marlin]

Try removing the front driveshaft, clean the slip joint splines and add new grease. Are these splins worn and loose? The clean grease may make a difference.

Marlin

[dok33 [OP]]

Ok, I'll check that too.  The only thing that would throw me on that one is that I still had some noise without the front shaft hooked up when I put the tcase in 4wd.  It wasn't nearly as loud, but I could still hear something faint.  I also tried unhooking the rear driveshaft and putting it in 4wd with the hubs unlocked and still had the noise.  Thanks for all the input!

[dok33 [OP]]

Well, I took it out today and definitely noticed that it got noisier as it warmed up, so I'm guessing that this implies a bad bearing?  Thanks.

[Marlin]

Have you removed the rear driveshaft at the t-case, torqued the 30mm output flage nut to 95#'s and restaked the nut?
Also, check the front left motor mount-is it broken?
It is very, very, rare to find bad bearing in the t-case
Check the oil-does it have water in it? How clean is the magnitic drain plug?

Marlin

[dok33 [OP]]

I should have access to a garage over the weekend so I'll check all of that and see if it helps.  I'm pretty sure the tcase oil is ok, I just put a new tranny in last March and put some fresh sythetic 75w90 in it, but I'll give it a look.  

I also noticed something else last night. I had to make a trip on the interstate and I had my hubs locked because of recent snow and I had a terrible vibration above 35mph that isn't there with the hubs unlocked.  It was pretty unbearable at 55 and I ended up unlocking the hubs for the trip back home.  I've never noticed this before, and I'm not sure if it's related to the noise issue, but I just wanted to put it out there.  

As far as restaking the nut, what's the best way to do it?  Sorry for all the questions, I've rebuilt just about everything on this truck, but there's always tons to learn!  I'm thinking if I have too many more problems I might just buy a welder and torch the front end off and put a solid axle under it  

[Marlin]

You may have dry and worn out brass bushings where the outer c/v joint goes thur the spindle.

We use a dull chisle and a hammer to restake the nut.

Marlin

[dok33 [OP]]

Thanks again for the help Marlin, you will definitely be getting my business in the near future!  I'm gonna call up my buddy this weekend and see if I can run by his shop and put the truck on a lift and try to pinpoint the noise.  

[84runner]

And make sure you got your front driveline falnges matted all the way  and are all tight this could cause the vibration

[donkeykong]

There is alomost nothing worse than having a noise not knowing where it is coming from

[dok33 [OP]]

Well, I put it up on jackstands today to try to isolate the noise and it's definitely coming from the tcase.  The fluid looks fine and I put a torque wrench to the rear output flange and it was still torqued to 95 ft-lbs.  I did notice some fluid dripping from around the front flange, but didn't get a chance to pull the front shaft and check the flange nut there.  Another thing I noticed was that there is about 1/16th (guesstimate) of an inch play if I grab either shaft and try to move it around.  Is this too much?  Thanks again for all the help, I'm fairly new at diagnosing drivetrain noises.  

[84runner]

Are you refering to the gear lash in the transfer case?

[dok33 [OP]]

Not the lash, the actual play in the flange (ie, up and down/side to side).  I haven't tried to re-torque the front flange bolt, so that will be next.  I'm pretty sure it's something in the front output side of the tcase, I just hope I it is an external fix like the flange nut etc.  I tore the front end down a few years ago and rebuit most of it and the spindle bushings were fine, so I don't think it's that either.  The main reasoning behind that though is that I still had a slight noise without the front driveshaft hooked up at all when I put it in 4wd (hubs unlocked too).

One thing I was wondering-is it necessary to un-stake the nut before tightening?  For the rear flange nut I just used a small punch and a hammer to tap the staked portion of the nut back out before I tightened it and restaked it, but I wasn't sure if it would just kind of un-stake itself as the nut turned.  Thanks.

[Marlin]

Even the factory manual tells you to unstake the nut. Do not do it. You were right, it will unstake itself as the nut turns. Simply get a 30 mm socket and tighten the nut to 95 ft lbs, then restake it with a dull chisle.

Marlin

[dok33 [OP]]

Thanks, I'm going to tighten the front flange as soon as the weather gets better.  Another thing I was wondering about was if it was necessary to brace the flange while tightening the nut.  I tried holding it with a screwdriver wedged under the body panel because I was afraid of torqing against the gears etc.

[84runner]

They see more torq than that when they are in use