rear end noise

[ansd12]

My neighbor has a 3500 which he uses to tow his fifth wheel. We took the truck for a ride the other day and noticed rear end noise. He has about 8k on the truck. The dealer adjusted the back lash in the rear end. Now it is especally loud at 10 to 15 mph. They said to let it wear in. The rear axle is the American type. Has anyone had this type of problem? I have a 2001 2500 which is quiet and he had a 2001 3500 which was quiet. Is rear end noise a characteristic of this rear end as compared to the Dana?

 

[NC_Mog]

There is no wearing in of gears. Do an archive search and you should find some good info on rearend gear noises or whining. The primary culprit is the low gear oil levels experienced by a lot of owners including me. I guess it depends on how low it was, how long it was low, type of driving, etc. as to whether you have subsequent problems or not. Problems have included pinion bearings, R&P wear, all the way to seizing at highway speeds.



Review the info in the archives, then get him to take it back in once you have educated yourself. Gears don't wear in. Period. Actually if a R&P are not setup correctly and you drive on it, iregular wear will result in never being able to get it right until you replace the gears.

 

[DBalmer]

Hi Guys:



My 2003 HO 4X4 Dually had about 500 miles on it (200 miles into a 1100 mile trip pulling the fiver) when the rear end started to whine. Loud. I took it to the dealer when I got to my destination, he said it needed a ring & pinion gears and bearings, but that it wouldn't let me down. Because of unknown amount of time to get parts (and he really didn't want to work on it) he advised me to get it fixed when I got home. A couple of weeks later my home dealer replaced the parts and set it up, now 1500+ miles later with no problems. I've got one of those rare dealers that have mechanics that actually know what they are doing instead of "service techs". The dealer told me that mine was the third (with the American Axle) to have the problem, the first one at 13 miles. This is a rugged gear set, GM has been using it for years (American Axle originally AM General). The problem is apparently the original setup at the factory, immediately wears the gears and starts to whine. I suspect that it you have no problem in the first couple of thousand miles, you won't have a problem.

 

[KCJackson]

American Axle is the old GM Axle division, not AM General (which was the former commercial vehicle division of the old American Motors that made postal Jeeps, military Jeeps, buses in the 70s, and the HMMWV/Hummer).



AA was spun off as an independent company similar to AC-Delco division becoming the independent Delphi Parts.

 

[sag2]

DBalmer

On page 235 of your owners manual it says not to tow until after 500 miles. Depending on the weight of your trailer, you might have cut it a little close and overheated the gear set. I would guess towing when so new had more to do with the failure than a bad gear set. There are some noisy ones out there, but if the gear set is bad or not set up properly it should be noisy from day one.

 

[Kilby]

Mine has always whined since I bought it. I had my dealer take a look at it and they "adjusted" the gears as they put it. The whining was between 65-75 mph and now it whines approx 68-75 mph but in a lower note. I think their attepts to fix the whine are useless but I have to let them do their thing. I'll be contacting them this week to let them know the noise is still there.



NC_Mog, when you say "There is no wearing in of gears", do you mean there is no break-in procedure? If that's what you're saying then I'd have to disagree with you. If that's not what you're saying, then nevermind.

 

[NC_Mog]

Yes, there is a break-in period. However, differential gearing is quiet from day one. There is no "well just let the gears wear in and they'll will get quieter". If modern automotive diff gears are set up right, then there is no noise. If you don't get it right, drive on them for any substantial time and they generate noise, you'll toasted a set of gears. Along with the noise is an bad contact pattern on the diff ring gear either on the drive and/or coast side. Once you "wear in" the bad pattern, 99% of the time you'll never get it set up right again.



Hope this helps. You're doing the right thing by going back to them.

 

[inarush76]

Picked up new truck, had 5 miles on it and a gear whine. Have an appointment to take it in on 24th. Am insisting on new gear set. Once one is noisy it will stay that way. Pulled cover to check back lash, and saw pattern way off. Was almost quart low when I checked level.

James

 

[DLeno]

adusting the rear end gears is a job only for experts, so I would be very careful to insure that the dealer has performed proper diagnosis before adjusting the gears. When I talked to AA, I asked about how well the "field" (DC service departments) were educated on how to deal with the new axles and the impression I was left with was that this education process is still under way. In particular, there is confusion wrt rear end noise (and the practice of adjusting the gears to get rid of it), the fill level, and the correct lubricant to use. What i do know is that the DC "star" line (technical assistance for dealers) has the latest info from AA.



by "proper diagnosis" I mean the ability to tell the difference between driveline harmonic noise and improper gear setup. You don't want somebody mucking up with the gear set-up unless they really know what they are doing AND they have the right and most current information from AA.



I'm not saying your gears should not have been adjusted. In fact it sounds like you got a good dealer that knows what they are doing. I'm just suspicous that a number of bad things could result from ill-advised technicians doing things like:



1. incorrectly assuming that the fill hole is the right fluid level indicator



2. puting in the wrong lubricant.



3. adjusting the gear setup to correct for a driveline harmonic noise.

 

[ansd12]

Thanks for all the good information from everyone. We both felt that the problem was not going to go away with just an adjustment and that has been verified with all the posts. I reviewed previous messages from the recent past and see a pattern, low lube level. I guess when a new truck is purchased, the first thing is to check all levels everywhere to ensure they are properly filled, but then again that's what the dealer is supposed to do. Thanks for all the input.

 

[DLeno]

Just be sure to put the AA perspective into your pocket too: that low lube level is not the common thread, nor is it a problem. Now then, the perception of a low lube problem is definately common, because that could result in an improper diagnosis, mixing fluds, etc. the position of the fill hole certainly contributes to this perception.



this is surely more complicated than the position of the fill hole, and from talking to AA and reading the info here I think at a minimum, the following are possibilities:



1. rear end quality problems at AA unrelated to lube level. for an axle that should be replaced, the dealer may try to adjust it instead.



2. rear end quality problems at AA unrealted to lube level. The DC tech incorrectly diagnoses the problem as low lube



3. harmonic vibration of the drive line. The DC tech incorrectly diagnoses this as improper gear set-up and tries to adjust the axle gears.



4. the tech tops off the axle with the wrong lubricant because s/he is mis-informed about and attention is drawn towards the fill hole position.

 

[ansd12]

I agree its a factory issue. However, if after checking all fluid/lube levels and seeing what is a low level indication, I would visit the dealer, its a brand new truck. The owners manual gives that information and I was surprised by the comments I read about low rear end lube levels. Is it the only cause of this problem, no, factory gear lash set up, lube level, lube type and load all contribute. However, if the lube level is low over time it can cause a problem, especially if the truck is pulling a big load. Checking all the levels is part of preventative maintenance and since its a new truck, with no track record and since low lube level was cited several times it would be a good thing to do before any damage is done.

 

[DLeno]

I think you may have nailed something. If the factory manual (written before they new about the AA fill hole issue) states (like the rest of the world accepts) that the fill hole is the right level indicator then yes we have mass confusion. However in the context of the AA statement, "low" levels means "below the fill hole" and has nothing to do with axle failures which are caused by other factors. I'm not saying that there were no axles shipped with fluid that is too low to avoid wear -- AA is saying that.



remember that lube level being cited many times is, according to

AA, an incorrect diagnosis based on the perception that the fill hole is the correct level indicator.

 

[ansd12]

I think this has been a very good dialog, I think some good information has come out of this. A goal we had was to find out if this was a unique problem to my neighbors 2003 3500 truck. It seems that some axles have a problem right from the factory, while not necessary a common problem but not untypical. In archive posts I did not recall seeing this information coming out. The manual thing and fill level is a whole other issue. It would be good to know what the right measurement should be.

Thanks for your input on this as it answered a lot of questions.

 

[yellow jacket]

I also had rear end noise. it would howl at 65-70mph. when dealer took cover off ring & pinion were BLUE. I might add that when I took delivery of truck & checked rear end at about 1000mi it was 1 /1/2 qts low. anyway dealer fixed it by putting a whole new rear end (minus tires & rims) in --no more noise. 47000mi half pulling race car trlrs one way.

03 2500quad cab slt 40/20/40 pwr seats, HO eth DEE 373LMTD SLIP, 2wd, jake brake, BD short shift, pwr trlr towing mirrors, trlr tow group

 

[DLeno]

The fluid was probably not "low" as far as being correctly filled at the factory. The 11. 5" axles ship with a fill hole in the casing that is higher than the fill level set at the American Axle factory. Probably your axle was one of the early ones with quality problems at AA and should have been replaced anyway, ignoring the fluid level confusion.

 

[inarush76]

noise

I am insisting on new ring and pinion, no adjustments. Mine has drive side whine starting at about 40mph, letting up on throttle noise is gone. They get one attempt to quieten this rear end, then a new assembly, then if not fixed, a new truck. (Can you say lemon law?)



James

 

[Wil_H]

So, what is the correct fill level for the 11. 5"rear end on the '03? If it is not the bottom of the fill hole how do you tell exactly how full it is?

ALSO, what would be the problem with filling this axle to the bottom of the fill hole?

Thanks in advance,

Wil_H

 

[DLeno]

AA has informed the DC star line how to evaluate for the correct fluid level. It turns out that they are filled via volume (number of quarts) at the AA factory, but there is no convinient way to do this in the field. AA is working on putting a scribe mark on the casing. I think they should just fill 'er up and move on with life, rather than insisting on this stupid "it isn't really low" line which only confuses people.



There is no danger, according to AA, in filling the fluid level up to the fill hole. clearly, that is the best solution (assuming you put in the right fluid, don't mix synthetic with non-synthetic and by all means don't put in no stinking friction modifier!)