Transfer Case Noise

Here is the background first-

I did a BW4406 conversion behind my 5.0 and 4R70W. I used an F150 front driveshaft and expedition rear driveshaft for the conversion. I put it all in and it all bolted up. Drove it for over 200 miles in that configuration, had no problems with it whatsoever.

I installed a 4" superlift recently. After the install, the front driveshaft was almost too long even when fully collapsed. I wedged it in there to get it on the road and had a noise starting from 35 mph up. It sounded like a worn out mud tire on the drivers side front, but slightly metalic sounding. I checked everything out and found that the driveshaft being too long had put pressure on the transfer case. I suspected the driveshaft was transmitting vibrations from the axle to the transfer case. So, I had the driveshaft cut down about 1.5" and reinstalled it. The driveshaft fit right in, with no problems and now has some room on the slip joint.

I didnt think I would have any more problems, but the noise is still there. Its not as loud, but still very annoying. I was driving about 35 and pulled the case into 4 high. The noise instantly stopped. Put it back into 2wd, and it comes back instantly.

I need some help here. Ive had all I can take of this stuff.

so when you are in 2wd you have the noise.
the front wheels are connected to teh hubs on your truck, which spin the CV's and axle shafts, diff and probably the front D shaft even when the t case is in 2wd

Its possible th epinion bearing on the front of your T case is toasted, the pinionr bearing on your front diff is toasted, a cv axle is making the noise, or a hub.

I would remove my front d shaft and see if its still there in 2wd, if it is then you just ruled out the t case pinion

410Fortune said:

so when you are in 2wd you have the noise.
the front wheels are connected to teh hubs on your truck, which spin the CV's and axle shafts, diff and probably the front D shaft even when the t case is in 2wd

Its possible th epinion bearing on the front of your T case is toasted, the pinionr bearing on your front diff is toasted, a cv axle is making the noise, or a hub.

I would remove my front d shaft and see if its still there in 2wd, if it is then you just ruled out the t case pinion

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No driveshaft = no noise

spin the front pinion d shaft flange on your t case by hand, see if it has play in it, makes a sound, etc. Check front diff pinion too, sounds like having the long D shaft in there may have blown a pinion

I suspect bearing or seal


Noise might go away
Check the trans case fluid level

what I don't get is why did it not make any noise before the lift if the bearing was bad?

Im going to go check the flange now-

you said your d shaft was too long (hahahaha thats what she said), no movement in the slip yoke
the superlift drop brackets made it even worse right?
This puts pressure on the bearings

Also you have a used T case that likely sat for a bit dry?
the d shaft is probably spinning all the time, even when you are in 2wd just because both front axleshaft spin. With an open front diff maybe not, only way to tell for sure is to have somebody watch as you drive it in 2wd if they can see th efront shaft.
that shaft spinning all the time = wear on the pinion and bearings.
Could have been made worse by the too long (solid) d shaft
Dont rule out hubs, cv's either, but since it goes away with no shaft, more likely in the diffy or t case
U joint in D shaft?

Hey can you take apic of your front D shaft while you have it out?
Do the D shafts I bought look like your Expedition shafts?
Nobody has posted pics of those yet

I got the driveshaft out really fast- ive done it a few times in the last few days

The flange is tight front to rear and side to side. No slop at all. When I turn it by hand I hear what sounds like chain noise, and can hear fluid moving inside the case. From what I understand the case has a fluid pump built in to make sure everything is oiled well.

The case sat on a shelf at the yard for a while, but it worked perfectly before the lift. The u joint that was on the driveshaft that I didn't change is a little tight, but is still smooth.

what no grease zerk? hahaha

so the front d shaft spins the t case oil pump? I thougt the rear shaft did because it needs to be oiled even in 2wd mode?

Hows the front diff pinion?

410Fortune said:

what no grease zerk? hahaha

so the front d shaft spins the t case oil pump? I thougt the rear shaft did because it needs to be oiled even in 2wd mode?

Hows the front diff pinion?

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It sucks that the u joint doesn't have a zerk. I couldn't believe it.

I assume the front may just turn the chain which would drag the oil upward, which could account for the noise?

Diff pinion has a little bit of rotational play, but no slop up, down, side to side.

could be a tricky noise to find.
I have resorted to putting all 4 tires in the air and CAREFULLY getting in, in gear, in 4x4, and let them start spinning.

Can you say jack stands and dont do this in the garage? (jack stand fail, tires hit ground, truck in living room) or at least point the truck towards the street?

Be careful getting under there!

I was able to identify my rear diff noise this way...otherwise it would have drove me crazy forever......

On closer inspection of the driveshaft, I found this-



See the small black spot on the yoke welded to the driveshaft? The rubber seal of the u joint looks like it has touched there, I don't know if it has touched during rotation, but why would it go away when I put it in 4hi?

anybody?

grinder time

but why would it go away when in 4 high?

I am going to jack up the front, rotate the front wheels when in 2wd and see if the u joint touches when turning. I don't get it, why would it make that noise in 2wd only?

mountaineergree said:

but why would it go away when in 4 high?

Click to expand...

Have you checked the pinion angle? Also, perhaps check for any play on the pinion?

The front diff angle is set by the Superlift bracket. I am not sure what it is.

From what I could tell, everything is nice and tight on the front diff yoke, side to side or top to bottom there is no slack.

What I really dont get is why does it do this with the lift and not before? I had the same setup before and it worked fine. The only change I made to the front end is cleaned out the diff housing and fresh gear oil.

Could the driveshaft angle be too steep? But if it was wouldn't it still make noise in 4wd?

That is why I am having so much trouble with this, it doesnt seem logical.

I would definitely check the pinion angle. I don't know what is "parallel" with the pinion though so I couldn't tell you what to put an angle-finder against on the differential housing. But in general as you may already know, the front differential should be pointing about 1 degree below the transfer case's line-of-sight. (The 1 degree offset is to ensure the U-joint's needle bearings are rolled around and greased)

since when did logic come into play when trying to find a noise?
It could just be that new parts = new noise, whether its they wore out at the exact time you install the new parts or whatever.
Logic will not always help you diagnose a noise, it could just be a parts time has come at the same time you installed something else.
Believe me with the BII I have found that to be true more then once, install a locker, rear caliper start acting up causing you to think its your new locker.....it just happens.

rotating noise in 2wd = put the truck in the air and drive it in 2wd SAFELY

Your front driveshaft looks different then the one i used. Im guessing the reason it makes noise in 2wd is that there is no force bieng applied to the front???