Well I got the truck back and the howling noise seems to be gone. They said they finally found a decent pinion ring and gear to put in it after going through 4 sets. I hope it stays healthy now!

 

I have the exact same problem from exactly 68 to 78 MPH. Back off the throttle and it goes away, bear down it comes back I did notice there was a TSB #17931 that said it was being investigated by engineering.

 

Picked up my '04 SC Lariat 4x4 in May. Advertised as the quietest truck on the road. While driving home, I heard the whine ~ but was excited about the new truck so didn't think much of it. Couple days later I mentioned that I thought this truck was suppose to be the "quietest"?????? Brought it to my mechanic (not the ford dealer) and wanted their opinion. They didn't drive it 30 seconds and sadly said its a shame that the makers of one of the best "rearends" in the industry are having troubles. From the sounds of what I'm seeing on the board, they should recall and get it straight. Should not have a rear end whine from a Ford differental in 2004. They should be way beyond that. Depth setting of the ring and pinion not quite right. They changed the ring, pinion and all bearings. If have 15K on it now and everything seems to be ok. They replaced my aluminum tube running boards because they were ozidizing already also. I have no complaints of the dealer, they have stood behind it. Thank God I have the extended warranty.

 

I took my 04 SCab 2x4 lariat in after I read all the posts and realized that I wasn't just being a whiner myself. They drove the thing and verified I had the bad rear end. My service rep said that they were going to replace the whole rear axle assembly. He said they tried doing the rebuild on a truck the previous week and it took all day. Their policy at my service shop is to replace the whole shootin match. He said Ford approved the solution. Wow. Sounds like a recall style fix. I'm just waiting for the parts. I will post the part numbers they ordered later.

 

Took mine in also, there were 2 othere in for the same thing. He said they were to replace the drive shaft. I told him the service numbers and he is looking further into it. I will not stop until the whole thing is replaced.

 

this is a crazy problem. I am a bronco owner but i was thinking. when every new gears are installed there is a break in procedure for them. all gears are this way. when you buy these trucks new how many miles had been on them. because proper break in for gears is usually around 500 miles similar to an engine. you shouldnt drive over 55 an for no more then 30 mins to an hour then stop and let them cool down. I know ford claims there gears dont need this , but precision,richmond and so on recommend the break in period on there stuff. this of course is not anyones fault but fords

 

Could you please elaborate on why you would have to "let your gears cool down" every 30 minutes to an hour? If the gears are getting hot enough to break down, wouldn't that be more a problem than just breaking in?
MK

 

http://www.oly4x4.com/newgearbreakin.htm

He's right about breaking in the gears..

 

Well I got the howl after 9000 mi just this week,, between 20-50 mph I had it all along and thought it was tires but it got real bad the last few days..

 

the cool down period allows for the gear metal to harden. this must be done in repeated cycles.

 

I own a 2004 F150 Lariat 4X4 SC, the gear whine started at about 6500 miles. The whine was only present under load and would go away when you let off the gas (coasting). The dealer told me the ford engineers were currently working on a fix and would not authorize the dealership to replace any parts/components for the whine problem.

At the 10,000 mile mark ford engineers determined it was a bad "cut angle" on the ring and pinion sets. So they came out with "new cut gear sets". The dealership replaced my trucks ring /pinion with the "new cut gear set". I now have 13600 miles on my truck with no noise what-so-ever...(I did not "break in" the gear set).

 

Yeah they told me "the teeth were too high" so that sounds like a "cut angle" problem, too. I got the new set and no whine.

 

Russel and Fordguy, unless Ford is buying gear sets from different manuf's that doesn't explain why most are not having rear noise problems.


I would ask how you treated your truck in the first 500 miles if you read the link I posted above about gear break in. I know when my 04 Scab had 60 miles on it the rear was running at 200 degrees on the infra red heat gun. I was only driving at 35-45mph for 10 miles when I stopped to check it. Now that's not screaming hot for gear oil, but I'll bet guys that head out on major highways at 60-75mph in trucks with less than 300 miles on their truck would seeing temps in the 300 degree range. At 200 miles and driving at 45-50mph my rear was down to 150-160 degrees. After 500 miles anytime I checked it it was never over 100-110 degrees and that was in July and Aug.

What I'm saying is when you read in your manual not to tow anything till you have 500 miles on the truck everyone assumes they mean the engine.. The rear needs more breaking in than the engine does. The simple fact you are letting up and hitting the gas again constantly is the perfect break in for the engine. If has a cooling system to keep it's temp right....your rear doesn't.

I've got 3900 on mine now and with the 1500 mile engine oil change it's due for another. This time I'll have them change the rear lube at the same time. At 4500 my rear(3.73LS) runs at about 100 degrees, it's quiet, but nows the time to flush the excess breakin steel that floating around in there out..and put fresh lube oil in there..

 

Hey, Guys I'm having whinning problems myself but the dealer is not fixing it yet. They did fix my loose rear suspension that everyone heard, repainted the front bumper for the rust, replaced the clutch pack for the shuddering at turns, reprogramed the idle, and I also have the vibration in the front end. I almost purchased the new freestyle for my wife two weeks ago but I'm not moving on anything yet. Ford has already bought back one SUV from me. I wish I had my 97F-150 back.

 

My truck is at the dealer right now and they said that they havent heard of any "new" ring and pinions. They are going to call the tech line. Does anyone have the part numbers of the new parts?? I'm hoping it will get fixed this time because on my first visit no work was done because Ford said it was " working on problem". Do these trips to the shop count toward a DSB?