transfer case yoke chirping

[brucecooner]

Some of you may have been following my ongoing mystery chirp after swapping an BA10/5 for an AX-15 (Novak).

The chirp developed over time, getting louder.

Upon recommendation I decided to replace the driveline joints and, once I had pulled the front driveshaft out and drove it 2WD style, the chirp went away!  Mystery solved, or so I thought.

 

Well driveshaft maintenance turned into driveshaft replacement with a new Tom's unit.

 

BUT, I finally get the new shaft installed and the chirp is back!

 

Solving this mystery requires some more context.

 

I locked the CAD on before the transmission swap, so the front shaft is turning all the time.

 

For some reason the front yoke on transfer case sent by Novak would NOT mate to the stock driveshaft.

I've looked at it, and it seems to allow you to seat a u-joint into it, but the bolt holes are definitely smaller, the old yoke has 5/16 x 24 bolts, and the "new" yoke's look like about 1/4 inch.

 

So the shop I took it to (I've used for a while, and generally reliable, and who have done these swaps before) put the yoke from the old NP231 into the new case.

And I'm guessing did it wrong.

That's why when the front driveshaft  was removed, the chirp was gone.  The shaft was no longer turning the front yoke.

 

So I'm about 99% certain I've got a singing front yoke in the transfer case.  Bummer.

 

At least I know how to make the noise go away now.

But I didn't buy a 4 wheel drive vehicle to delete driveshafts.

My other option is put the CAD back in use, but I think in that case I'd get one of those cable systems that engage them.

I'll admit, I'm only going to be in four wheel drive rarely, so the CAD might get used once or twice a year (if I'm lucky).

 

More importantly though, how worried should I be about this noise?

 

I don't want to get out on a trail and put it in 4 wheel drive and then blow up the front yoke and/or pinion.

I'll definitely call the shop and fuss about it, this should be well under warranty (if I can trust them to fix it right).

 

 

[89 MJ]

I think calling the shop and having them fix it is the way to go. If it were mine, I’d be concerned about the noise because it isn’t supposed to be there. That doesn’t mean it’s a major issue, but it’s not correct, therefore I’d make sure it gets fixed. Putting the CAD back is just a bandaid. It’s not actually fixing the problem. 

[derf]

One possible source for the chirp is a bearing going bad. Put it in 4HI with the driveshaft out and see if you still get the noise.

 

It's also a good idea to check fluid levels.  Make sure the case is being lubricated properly.

[brucecooner]

3 hours ago, 89 MJ said:

I think calling the shop and having them fix it is the way to go. If it were mine, I’d be concerned about the noise because it isn’t supposed to be there. That doesn’t mean it’s a major issue, but it’s not correct, therefore I’d make sure it gets fixed. Putting the CAD back is just a bandaid. It’s not actually fixing the problem. 

 

I assume pinions/bearings aren't supposed to do this so yeah, it's got to be addressed.  And like I said, making the noise go away is just putting off the problem to another day.

 

1 hour ago, derf said:

One possible source for the chirp is a bearing going bad. Put it in 4HI with the driveshaft out and see if you still get the noise.

 

It's also a good idea to check fluid levels.  Make sure the case is being lubricated properly.

 

The TC has had a very slow seep from the drain plug since I got it back, I'll need to change it after a breakin period and I need to research how to better seal the drain plug.

On that note, I checked the level once the noise got loud, but it was still up to the fill plug hole.