Whining noise (speed dependent)

[rtbrjason]

This weekend I changed my fuel pump (replaced with new motor craft part) and while the tank was down swapped out the transfer case motor. The old motor worked fine but was almost completely rotted away. Also swapped out the transfer case fluid from a cheap ATF to Mobil1 ATF.

First trip out and it's running fine, 4hi/lo works, but once up to speed I'm hearing a whining noise. It's not too loud, kind of high pitched and the windows have to be down to really hear it clearly.

Any ideas what it might be? It was definitely not there prior to the work mentioned above. Thanks for any insight.

 

[Exia]

This weekend I changed my fuel pump (replaced with new motor craft part) and while the tank was down swapped out the transfer case motor. The old motor worked fine but was almost completely rotted away. Also swapped out the transfer case fluid from a cheap ATF to Mobil1 ATF.

First trip out and it's running fine, 4hi/lo works, but once up to speed I'm hearing a whining noise. It's not too loud, kind of high pitched and the windows have to be down to really hear it clearly.

Any ideas what it might be? It was definitely not there prior to the work mentioned above. Thanks for any insight.

Are you sure its kicking out of 4wd ??

 

[rtbrjason]

I'm fairly certain that it is, but will go out and move through A4WD, 4HI and 4LO again. It does seem to go into each mode though so I believe it is working. I've also got a switch to disable A4WD and the noise is still present.

 

[rtbrjason]

This is definitely coming from the transfer case. I am in 2wd as I found some snow to test in. Must have something to do with the installation of the motor or the fluid change. Going to make sure fluid is definitely full and prob pull the transfer case motor and see if there is anything misaligned or that needs adjusting..

 

[rtbrjason]

My buddy put it up in the air last night and we got it up to speed. Noise is definitely coming from the xfer case.

One thing to note, when we drained the fluid to put synthetic in a couple days ago, the dex3/merc that came out was solid black after only having been in there for a couple thousand miles. We drained it again last night and the M1 ATF wasn't in terrible shape, but putting dex3/merc back in didn't make a difference.

With the upper speed sensor out, he was able to feel the chain. It's really loose so we're assuming this thing has been on its way out for a while and the fluid change maybe "aggravated" it for lack of a better term.

I guess I'm going to start shopping around for a xfer case.. I'm not sure where I will get one from yet but am open to suggestions. I've dumped a ton of money into this truck now (almost $8k including purchase cost, parts and labor where needed), so I'd like to get something that will last.

 

[rtbrjason]

Anyone have any thoughts on why the fluid that came out of the xfer case was black/dark grey? It was dex/merc with only a few thousand miles on it.

I did put some lubeguard friction modifier into the transmission to cure a shuddering into OD. That stuff was really dark.

Since the xfer case and transmission both fill and drain separately I'm assuming they don't share any fluid? That's the only reason I can come up with as to why the xfer case fluid was so dark though.

At this point I've put a few hundred miles on it and this whining noise seems to have subsided.

 

[BANGEREXPO76]

If everything is shifting/working it probably just needed to get readjusted. Hopefully it continues to quiet down and gets back to normal.