Ive recently noticed a howling sound coming from the rear end of my f150 from speeds of 45-60mph it goes away as soon as i get to 60mph and starts again very slightly at 80mph. Im sure its the pinion and ring from everything I have read online. a friend told me that it could be the pinion gear is worn out or it needs re shimmed or something. what parts should I look for to get this fixed? could it be a fluid issue? I dont want to have to spend much more on this truck....I love it but it seems like i find a new "noise" every week. Ive always been a chevy guy and to my surprise I REALLY like driving this truck and i want it to work out. What should i expect to pay for a repair like this? BTW it is and 04 FX4 with 84k on it.

 

I would check the fluid level immediately. It could be just that simple. Also check for any leaks, dents, abrasions and Make sure the vent tube is not clogged

 

I have an 04 with 3.73 LS rearend, 80000 miles, same exact symptoms. I have changed the gear lube about 5000 miles ago and actually seemed to increase the sound. I have seen threads about some issues with this year and Ford doing some warranty work on them. I am driving it and waiting for the other "shoe to drop" so to speak.

 

You have the ls, did you add the friction modifier?

 

Yup, prior to changing the lube I was getting the clutch shudder issue when turning sharp, reverse mostly. After fresh oil and two doses of modifier that went away. Maybe the noise is related to the LS clutches? Driveability does not seem to be affected.

 

I have the shudder too but the whining noise is what drives me nuts. I've thought about changing the fluid and modifier but I don't want to spend 100 on that and then take it to a shop where they will drain it all and charge me 100 for more fluid. Does this sound like pinion problems? If so what parts will I need? My dad has worked on older vehicles and said something about a crush tube

 

The bearings are the problem from what I understand, my father had the same issue with his '04 and took it to a shop that the local Ford dealer outsources all their axle work. They replaced all the bearings in the whole axle as well as the ring and pinion, the tech didn't think there was anything wrong with the R&P as it wasn't showing any wear but since installing a set is mostly labor it was just as well rather than not and have to pull it again. The Ford service bulletin for this problem specifies changing all the bearings.

 

Had a pretty experienced friend look at it and drive it today. He said its most likely the shims or the preload needs adjusted. He doesn't think it's bearings because it doesn't happen at coast and there are no leaks. He also drove the truck a lot and felt the axle and case for heat and said if it was a bearing it would be hot somewhere. He also said the gears should be fine because there are no metal shavings at all on the cap just very tiny particles that made the bottom of the cap feel spongy mixed with the oil. These were microscopic particles and there wasn't much of them. Would the shims or the preload be out of adjustment? I'm fairly sure nobody has ever been into the rear end or changed the fluid so can they get out of alignment on their own? Also I talked to a guy at the dealership and he said it probably has the 90 weight fluid in it and it should be changed to the 140. Could that solve the whining?

 

If you take it to a dealer they are going to do the repair Conanski described. It's fords approved kit for repairing axle noises on the 04 and 05 trucks. If it does have 75w90 it will be replaced with 75w140.

 

Oh trust me this truck will most likely never see a ford dealer. I'm not stupid enough to pay for parts that are perfectly fine. There's no reason a 2 hour rear end job should cost 1500$

 

Im really looking for a straight answer on this. No metal shavings, no leaks, and the noise is from 50-60 mph only when under power. Should I try to just change the gear oil? Have the shims and pre load checked?

 

Your one heck of a mechanic if you can properly rebuild a 9.75 rear end in 2 hours.

 

Ring and pinion should take around that time. Either way from what I'm hearing it doesn't sound like gears and bearings because there would be more problems.

 

In my 05 all the bearings took a dump at 80,000. just replaced the bearings ($800.00) and yes it takes more than a few hours. Its been 40.000 since and no more problems yet.

 

Funny I should stumble across this thread. I just picked up my 07 F150 4x4 with 3.73 gears from the dealer today after having it dropped off for a howling noise between 45-50 mph. They said there was excessive wear on the ring and pinion and replaced the bearing assembly. On the way home from the dealership, I heard the noise again. Looks like I will be giving them a call first thing on Monday morning.

I had a similar noise about last Oct or Nov and it turned out to be a bearing in my trans. Thankfully I have the top of the line extended service warranty and everything has been covered... even the upper ball joints (which my truck is on its third pass side upper ball joint). The most recent one prior to this time was replaced just over 12,000 miles ago. Im really beginning to question the durability and quality of Ford parts anymore.