Attemping axle whine correction

[GDouglas]

I have about 25k on the truck now and I am looking to change my rear axle fluid with 75W-90 synthetic per American Axle recommendations. I have also just recently noticed a whine from 65-70 MPH on a slight pull, goes away on hard pull or coast. While the cover is off I am going to do a gear pattern check to see what I have to do to correct the whine. From my past dealership technician experience, a gearset does not audibly whine if the gear contact pattern is correct. Usually, if the pattern is off center concerning tooth contact depth, I have found that changing pinion depth will correct the issue. In the other direction concerning where the pattern is located between the ID and the OD of the ring gear, then adjusting backlash usually brings the pattern where it needs to be.



I have a shop manual on order but not in my hands yet. I was wondering if someone here has had some experience with the method of adjustment for setting backlash on the 11. 5" American Axle before I take the cover off. I am hoping there are some threaded collars instead of shims behind the carrier bearings. If the American Axle has some sort of threaded adjustment and if all that needs to be done is a backlash correction, then the correction shouldn't take long at all to do.



However, I have run into Ford and Chevy gearsets in the past where you can get a good pattern on one side of the teeth but not the other. In cases like that you have to comprimise on the best pattern you can get or try another gearset. Sometimes you you only end up moving the noise to a different speed. Hopefully I won't run into that problem.

 

[Gauthier]

The 11. 5" AAM does have threaded adjusters similar to the Chrysler 9¼" axle. I wish you success, but I haven’t seen much success with changing the backlash or pinion depth once the gears have been run-in for any length of time. Good luck.

 

[KevinWatts]

I don't have this problem with my truck but it interests me. I setup 3 or 4 axles a week. It would be interesting to see what the backlash and pinion preload is before you change anything. The first thing I'd look at before changing anything is the carrier and pinion bearings. I've had new jeeps with only 5k that had bearings that were all pitted and scored. It also doesn't sound like a pattern problem if it just started after 25K. I haven't had one of these apart yet, does it use shims or a crush sleeve for pinion preload?



Let us know how it goes

 

[Gauthier]

Crush sleeve

 

[KevinWatts]

That being the case... that would be the first thing I'd check.



Here's a little troubleshooting info: http://www.ringpinion.com/tech/techind.html



scroll down to diagnosing noise

 

[GDouglas]

I got around to taking the rear end cover off today and did a gear pattern check. On the pull side of the teeth the pattern looked textbook perfect. On the coast side, the pattern was just slightly high but not running off the top edge of the teeth. If I were to change anything it would be pinion depth to help the coast side a little bit, but since the patterns were acceptable, I just decided to change the fluid. Backlash was at . 006". Since my whine noise is only on a slight pull between 65 and 70 MPH and quiet when coasting, I decided not to change any settings and just stick with the fluid change.



With such an excellent pattern on the pull side, I am still wondering where the whine is originating from since I only hear it on a slight pull between 65 and 70. Maybe some of the talk from other rear end topics about DC trying some different things with the driveshaft will eventualy end up in a fix later on.



At least I have the satisfaction and peace of mind now that the contact pattern is OK and that I won't be stranded out in BFE somewhere in the middle of the night with ring and pinion failure.

Until if and when DC comes up with a solution, I can keep the radio volume up where it usually stays, about 1/4 to 1/3 of the way up and I won't be able to hear the whine much at all.

 

[Nellie]

this is nellie the dealers tell me the axel whine is ok . this must be the new way they build axels now, very upsetting .



nellie

 

[Prairie Dog]

Whoa Nellie (sorry) the rear end in mine is as quiet as any other vehicle I've ever owned. I must be lucky or maybe it's the pure life I've led?

 

[Gauthier]

GDouglas:



Did you take any pictures of the drive and coast side of the teeth?

If not, I have some pictures I took of my howling axle if you would compare to your truck.

 

[drrhoades]

Is it a whine or more of a growl? If more of a growl it could quite possibly be your bearings.

 

[GDouglas]

Unfortunately, I don't have any pictures of the patterns I obtained. The noise is definitely a gear whine and not a bearing growl. In all my past rear end experience, a bad bearing will make noise all the time whereas a gear whine will be tourque sensitive and only happen either on a coast, pull, or float.



For now I am not going to loose any sleep over it since my contact patterns on the pull and coast side of the teeth are acceptable. With this fact I am comfortable that nothing will tear up and leave me stranded on the roadside. I am planning to look into the driveshaft fix that is reportedly out for the 2WD models that is supposed to help with the whine.

 

[RTWhitfield]

I have already had the dealer replace the rear axle gears in my truck. It started a loud whine at about 10,000 miles and got so bad at 15,000 something had to be done.

The dealer replaced ring and pinion and all bearing and seals.

That fixed it for now, I hope it does not start again in another 10K. That way I will not have to go back to the dealer and get it replaced 10 more times before my extended warrenty expires.

Tom

2003 3500 DRW HO auto 2WD 3:73