Odd growling noise when hubs are engaged and in 4x4

[hallaert]

My 2001 f350 makes a growl noise when the hubs are locked and 4x4 is engaged. I have shift on the fly 4x4 and warn manual hubs. Any ideas ?
Thanks guys!

[blue99stroker]

how do the U-joints look?
also have you ever checked the fluid level in the pumpkin. my gf's brother ran his dodge out of gear oil and it howled/growled horribly.

side note: have you ever changed the fluid in the transfer case? i did mine last year and it was plain nasty.

[ProOnThaSnow]

Mine is doing the same actually, and I can't figure it out. The diff is full, and I've got Mile Marker hubs - at certain speeds it isn't noticeable, or I should say at certain power? If I let off the throttle it'll make the growl and if I get into it it will do the same. I did balljoints, tie rods, seals, etc probably 20K ago and at that time the front U-Joints were both tight as could be. I'm almost wondering if it isn't something to do with the T-case, but I'm not sure - I've ran it as is in some crappy weather in 4wd and although loud and making noise it seems to be working properly? I sure would like to figure out what the hell it is, because it is rather annoying and being that I commute 320 miles each way for work several times a week in Montana/ND winter I would like to not have the worry of it taking a **** on me in the middle of nowhere.

[blderman]

My did the same thing, rebuilt the front driveshaft including the double cardan w/centering ball and the noise is now gone. I use 4x4 very infrequently but the double cardan joint was toast.

[PowerStoke99]

Mine did the same thing and only when the truck was in 4x4. i found out that my pinion nut on the front pig backed off. so i drained the pig checked the gears for damage and when i found no damage i tightened the nut to test to make sure the loose nut did not damage the inner or outter bearing. which it did not im my case. so i pulled the nut off and put a new seal on the pinion and put some red lock tight on the nut and tightened the nut back to torque specs. resealed and refilled the pig with gear lube and while under the truck i put new u joints in the front drive shaft and ever since then no issues or noises and i have been plowing snow since. hope this helps yall out

[ProOnThaSnow]

I am assuming everytime it says "pig" you mean "dif"? lol.

I'll have to look into that when I get back home - on the road with my '00 right now for work, but want to get that and a few other things squared away on my '01 so she's ready to tow for race season!