I have a strange whine I was hoping somebody could help me with. It is a high pitch whine like a bearing. It occurs when accelerating, cruising or coasting, but not when braking. It is speed dependent, not rpm dependent. It generally starts above 20 mph through as fast as I dare take it. Gets louder the faster I go. Below 20 mph or so it generally does not occur. I just had the rear end rebuilt by a reputable shop about 9 months ago. Truck has over 130k. I replace the front wheel bearings everytime I do a brake job. I have heard front bearings go bad before and this does not sound like bad front bearings. I haven't done the U-Joints yet. They are probably due. Could this be worn out u-joints? Any other ideas?

 

sounds more like the ring and pinion may be off and causing whine in the rear differential?

 

It's most likely your pinion bearings in the rear end. Same exact thing happened to me, was most notable around 55MPH, replaced the pinion bearings and other seals and bearings near the rear diff, and the sound was gone.

 

I found the problem today. I went to check the diff. fluid today to see if it had any metal flakes or other problems and behold, no oil! You can imagine my surprise since there are no spots on my driveway indicating a leak. I have an aftermarket cover with a fill port on top, so I fed a metal strip into the housing as a dip stick. I measured less than 1/4" of fluid which is probably just the residual fluid left after it was drained. I had the rear end rebuilt last year for the second time. The business that did the first rebuild around 100k never cleaned the housing and left all of the metal flakes in the rear end. This caused it to only last about 25k. The next rebuild (by a different business) was done very well. I inspected all of the work before they closed everything up and checked the backlash. I ran it for a few months and then had the fluid changed at a Ford Dealership right before I moved to North Carolina from Texas in January. Normally I do it myself, but with the packing for the move I didn't have time. Luckily they warrenty any repairs for 12 months or 12,000 miles and I haven't hit that yet. My problem now is the dealership that did the work is back in Texas. I'm waiting to hear from them and see how much hassle they are going to give me. I going to ask the dealership for the rear end to be rebuilt with new bearings and seals. Depending on what the gears look like, they might also have to be replaced. I've put about 6K on the rear end. I can't believe it has lasted this long with no oil in it. Anybody got any pointers on dealing with the dealership?

 

I am having to replace the differential bearings in mine. Hopefully that will fix it. It starts whining about 15 mph and just gets louder with speed. Sound come from diff only. Jack it up and give the tires a spin, it wont whine, just kinda knockin a little. Spun the drive shaft and it made no difference. diff beariings are $11 at autozone. I will replace mine Monday.

 

Well, I took it to a local dealership here in NC to document everything. We drained it and it only had 2 quarts in it. The mechanic agreed that there are no signs of leaks anywhere on the rear end. Common sense tell you if it wasn't leaking then they didn't fill it. With my aftermarket cover it should have taken about 3.5 quarts. The mechanic refilled it and ran it on the lift and drove it. He said he is hearing noise from the left rear wheel bearing and the pinion bearing. He agreed that the wheel bearing failure is most likely from being low on fluid. He was not sure about the pinion bearing as he is unsure if two quarts would have reached up to the pinion bearings. I mentioned that runninng low on oil will heat the rear end up more also and could contribute to bearing failure. He said that is possible, but he is not sure.

I was hoping these guys were going to work with me and give me straight up answers on the damage and that low oil level would definetly cause it. Unfortnately the service advisor I was dealing with changed her atitude once she talked to the service manager in Houston. It turns out that the reason the guy in Houston recommended this dealership is because they are owned by the same parent company. The service advisor here in NC did not know that until she talked to the Houston Dealership this afternoon. So much for an unbiased opinion! Now she is telling me that even though it was low on oil the mechanic doesn't think this caused the bearing failure. No wonder he recommended this dealership to take a look at it. This really irritates me when I was looking for an unbiased opinion on it. I'll try a different dealership with no relationship tomorrow and then call the service manager back and see what he says.

In my eyes it is pretty clear cut.

1. It had a little less than two quarts instead of 3.5 quarts
2. There are no signs of leaks on the rear axle or on my drive way.
3. Running about half full of oil will starve the wheel bearings.
4. Running about half full of oil will cause a significant increase in temperature shortening the life of bearings/seals etc.

Faced with this, why are they being so stubbern about not owning up to what they did and fixing it?

 

Did they say anything about the aftermarket diff cover? Hope they don't try to use that to their advantage if they try to get out of covering the repairs. I'm sure their lawyers included some fine print in the warranty about aftermarket parts voiding their liability...as far as I recall, the Magnusen-Moss warranty act says they can void your warranty IF they can show the aftermarket part contributed to the failure. They might have a strong argument there even though they SHOULD be at fault for not filling it to full. Keep us posted and good luck.