do you have AOL, if you do my screen name is jmut9, i have a few more questions to ask you. i think you for your time. so that could be the reason it's humming and sometimes feel a vib.

 

No I don't have AOL. I use cable modem.

I've been racking my brain for the last several minutes, and I cannot come up with an answer. In twenty years of driving semis, I've never made that connection. But I am curious whether or not the vehicle your driving has been raised or lowered by yourself or a former owner. Because it could be true that your attack angle is incorrect, and is only correctable when rearend is tilted/rotated with shims forward or backward depending on whether vehicle was raised or lowered.

On contacting me, you can do that by clicking on profile on any of my replies, and clicking on send email to this person.

 

it's stock hight, everything it pretty much stock. when it started to hum is was after i parked it for two months with out driving it sep to dec. but back when it was warm out it never mad a humming noise. so i don't know what is going on with my baby.

 

Before you started driving it again, did you first check rearend fluid, and grease u-joints. And of course carrier bearings don't use lubribation and the rubber does become dry and fragile after a period of time. As far as axle bearings, they too are prelubed at factory and are non-servicable. That means after a period of time, they can dry out and go bad (stop turning smoothly).

Have you already verified that u-joint is not going out. Needle bearing must stay lubed at all times.

 

well a week or so ago i was doing an oil changed and while under there i looked at the drive shaft, there was some side play in it where it go's in to the tranny and the carrier. when i brought it to the tranny place they checked all the fluids and said that the rear end was down some and the tranny a qt. or so. they also said that the springs in the tranny are worn and are causing it to shift hard from OD to D and D to OD. other then that the tranny feels fine.

 

I'm not making the claim that you don't have a problem in the rearend, I'm just saying that sometimes like in my case, automotive shops also make mistakes that will end up costing you a fortune. There are several things that can cause vibration, and noise.

-U-joints
-driveline expansion joints / slipjoints
-carrier bearings
-axle bearings
-differential 3rd members
-broken/cracked brake drums
-driveline attack angle
-broken axles
-transmission
-out of balance driveshaft
-loose transmission to engine bell housing
-loose/cracked/broken/bent/warped flywheel or flex-plate
-wheel-end bearings
-out of balance crankshaft / bad vibration dampner
-bad tires

As you can see, one or a combination of above items can be faulted. But usually, driveline or rearend result in howling. When my axle bearings failed, it was without notice. It just happened. And the more I drove on the failed part, the worse it got. And one way you can tell if it's the axle bearing or rearend is if sound travels from right to left. That's an axle bearing failure, but if sound doesn't appear to travel, then it's a u-joint or 3rd member failure.

Everytime you change your oil, make sure all zirt fittings receive grease, and all fluids are checked.

 

i guess it must be the axle bearings that are going, the tranny place told me that there worn, but i was looking to see if anyone else had an input. well I guess I'll save up for them, how much do you think it should cost to replace the axle bearings at a grarage, cause I don't have the tools or space to work on it, I live in a condo and there not so happy about using the parking lot to work on your autos. thanks for all the info.

 

If it is in fact your axle bearing, the parts only cost $21.00 per side and shop labor is typically $68.00 an hour.

If it is your 3rd member (differential/pig) about $150.00 used out of junk yard + shop labor and misc parts.

If it is your carrier bearing that carrys the driveshaft, I can't see them for no more than $50.00 + shop labor.

I'm not going to try and scare you. You have a problem and it's asking for attention. When you go to these automotive shops, make them use words that you clearly understand whats going on. And be wary of some shops that will fix just anything just to get your money. But realize too that even the most honest shops will make mistakes. It's human nature. They might claim its one thing when actually its something totally different.

You don't want guess work, you want answers. Make them tell you exactly what is wrong, not what they think is wrong. I've already given you information to help you pin-point your problem. The information I gave you is from experience. These shops pay mechanics for the knowledge they learned through experience or school. They know how to test your truck to give you a concise answer and you deserve it because your paying for the work. Take your truck to another shop, or even Firestone/Gemini. Because I'm affraid you'll end up getting taken and end up paying alot more for the given repair than you should have. The mechanics at Firestone/Gemini service centers are all ASE certified in their individual fields. Maybe they can give you a definative answer to your problem. And they'll tell you exactly how much it will cost. Thats just my offerings, you may use whomever you want. Hope you have better luck. If not find a friend who might have a garage and do it yourself.

 

thanks, but what i don't understand is that it goe's away for a while like 10 miles or so + or - then comes back. but if i get the truck up over 70 it will go away. does that sound weird or what? but thanks for your time...

 

I have a theory on the 70 mph rule but not ready to share that yet. I know you have a part that is in the beginning stages of failure. Just what it is I don't know. As that part gets closer to failure, it should make itself know. Any one of 5 items could be at fault. But your problem seems to be somewhere from the driveshaft to your rearend. Well not your rearend but the trucks rearend. You know what I mean.

-U-joints
-Carrier bearing
-input shaft or it's bearing
-3rd member
-axle bearing

Most of those things above you can check yourself. The 3rd member and axle bearing can be checked by removing wheels and brake drums. Remember to properly detect axle bearing failure, it has to be UNWEIGHTED. U-joints and input shaft should have no movement or play up or down. Be sure to secure with wheel chocks, and place in neutral for accurate test. Carrier bearings have some give but not that much. Sorry I can't be more helpful.

 

input shaft in the the tranny does have side to side play, is that ok or it that the prob.?

 

That shaft you refer to is the transmission output shaft. The input shaft is in the pinion on the front of your differential. If your transmission is bolted to your engine, you don't have access to that shaft. Just thought you'd like to know.

When you say side 2 side play, are you talking a little or a lot? Do you also have transmission fluid coming out of that seal on the back on the transmission?

Any play inside the transmission that could case alot of play at that point would surely damage seal causing fluid to leak at that point.

In that area, there are differences between light trucks and semi-trucks. On semi's, there is a short shaft coming out the back of the tranny where a yoke is bolted on. I have had those failures before. But in light trucks/cars, the spline shaft of the driveshaft just slides right in the back of the transmission. A seal at that point prevents fluid leaks. I personally have never experienced failure at that point. I don't know of any failures in that area that could cause the noises your hearing.

Musically speaking, I know of many automatic and manual transmissions that love to sing, but they don't howl.

Something just came to mind that I forgot about. On Ford rearends, an improperly shimmed carrier inside differential 3rd member does like to howl and other than being annoying, I've never hear of the sound being attributed to any failures based. I don't know if this has any play on your problem, but I thought I would share that. The sound I think you are talking about I still think is in rearend. Another simpler check you can perform on rearend involves removing drainplug, and allowing just enough fluid to come out for a sample then retighten plug. Put some of this rearend fluid on a white piece of paper and see if you can find any metal shavings. Also put some between your finger and thumb and see if you can feel metal shavings. I did forget about that, really. No shavings, no problems. I would still check those axle bearings.

 

you know when you put a truck in to 4 wheel drive and you get that sound, well it's just like that but louder sometimes then other times.

 

I have no experience with 4X4 light trucks. However if you talking about Ford's atypical "clunk" sound you get like when placing transmission in gear, and my car with Ford 9" rearend does it too, that's the carrier inside the differentials 3rd member. That particular sound while ugly as it is, is not harmful. That atypical "clunk" sound can be eliminated by having the carrier shimmed.

Now get this, if that carrier inside the differentials 3rd member has too much play (which is seldom) it can be bad to your rear end. Both your axles terminate in that carrier and tie into the pinion gear which is rotated by the driveshaft. Remember that these pieces in the rearend work on right angles.

If that is your problem, the just secure your vehicle from moving, jack up rearend and secure with jack stands. Drain fluid from rearend. Then pull both axles, and drop driveshaft then with a friend or transmission jack under 3rd member, unbolt 3rd member and remove from truck. Get an exact unit with same ratio to replace yours.

Clean out the inside of differential housing removing all metal shavings, and clean off old gasket material from front of housing where 3rd member mates. Also remove both axle seals like I mentioned before and replace with brand new ones. Be sure to coat both seals before and after installation.

Place new gasket on housing and place 3rd member back into housing. Torque to spec. While axles are out, check axle bearings and replace them now if they are questionable. Then place axles back inside axle tubes carefully. Don't let axle ride on new seal lips. Rotate and push them back into their seats and reverse your removal procedure. Fill up differential with brand new fluid. I used 85W-140 gear oil in mine. Refer to shop manual if you have questions about that. Usually you just place fluid in refill hole until the point that it just starts to drip back out. Replace plug, and then check u-joint before hooking back up to rearend. Nows the time to replace u-joint if one is needed. Replace driveshaft. Put truck back onto ground your done. Drive your truck and check for any leaks. All this information is listed in your trucks service manual which they sell on this site. Its not that hard a job, but like in your case you need to find someplace other than your apartment complex to do that. If you want the shop to do the work, make sure you get all costs up front.

 

mine did the same thing then the axle seal started to leak at the peak of the increasing whinning, at that point I replaced my axle on that side and the bearing and the seal the axle seemed to have some pitting that eventually wore the bearing then the seal.
good as new now!