I have searched and come up with mixed reviews. My 07 5.4 KR 4X4 has 228xxx miles. The fluid does not smell or look burned. It is full to its mark and not low. 4X4 engages and works, hubs lock and unlock with no grinding

The Problem:

While driving I hear an increasingly louder whining noise, ( like what a bad power steering pump sounds like). Mostly from 40mph and up. It will go away when you let off the gas and back when on. It will not do it at idle revving the engine or turning the steering wheel, only while under load at speed. It shifts good, OD seems to work fine. I have no clue how the PO serviced the vehicle. I do know they towed with it as it has a popup ball hitch in the center of the bed for a gooseneck. No codes are present on my scanner. Any suggestions aside from take it to a trans shop? I have read some to say servos, as well as torque converter might be bad. Any help is greatly appreciated.

Thank you

 

You sure it isn't rear end whine?

 

Nope, I have not thought of it. I am about to do a pinion seal and re-seal the rear cover on the rear as they both have a small leak. Wont do that for a week however as we are moving this weekend. Thanks for the suggestion. Ill change the oil in the front diff while Im at as well.

 

I have the same issue with mine. It's the carrier bearings in the rear are worn. I just do regular maintenance and let em ride. If the humming changes then I'll rebuild the rear end.

 

Just finished moving finally. Have had no chance to change fluids. The rear diff fluid was chocolate brown but full and the front diff has water in it as it is milky. That is the project for this weekend

 

Update....

did the rear diff today. Not sure yet if it cured this problem but man was that nasty.

 

Rear diff was the problem the whole time. Thanks for all the help.