Hi forum. Attached are two photos of my rear differential ring gear. The first attachement, Bessie1.JPG, highlights with a red circle a worn area on ring gear that I don't think is from manufacturing. The second attachment, Bessie2.JPG, highlights with a red square the contact area
with pinion that appears not to be wearing evenly. In both photos one can see the "heel" side has more material than "toe" side.

Should I have serviced or leave it alone ?

Sven

 

pics arent showing.

 

missing pictures attached

 

That's not a bad gear mesh, so if it's not howling or grinding I'd leave it alone. Any noticeable chunkage inside? I think the circled part is the way it came off the line since it appears to be consistent across the teeth and big chunks of broken gear is about the only thing that could do that in an abnormal fashion.

 

>Any noticeable chunkage inside?

No chunkage, about 1/4" of very fine buildup on magnetic plug. Thanks for reply.

Sven

 

I just pulled 'some' flakes and a little fine build up off of my drain plug last week. I've got no signs (audible / tactile) of trouble that I can tell. I think these trucks are so overbuilt in the rear that there's plenty of metal back there to handle some significant issues before there's breakage.

I wouldn't worry. I was surprised to see my small chunks / flakes, but the fluid was still nice and clear so I won't worry.

$ 0.02

 

Why did you open it all up?

 

I changed the fluid in the front diff today and attached those photos as well. Noticeably more even wear pattern and a very slight strange wear area ( indicated with red circle as before for the rear differential photos ). Fluid in front was also much cleaner than rear. Somebody asked why I pulled the covers, because I was changing the differential fluid. I've always thought there was too much driveline play ( posted a few years ago about it ). Two visits to dealer about this issue in the past with dealer saying it felt normal.

Thanks for all the replies,

Sven

 

I think if you get some ring gear paint and run a pattern check you will find that the gears are wearing correctly. Whining, howling, or grinding are usually indicative of a differential problem. Chances are if you are not hearing anything unusual, you do not have a problem.

If your vehicle is out of warranty, I would not waste the money taking it to the dealer. If you do decide to have them look at it, they most certainly WILL find a problem that requires about $2000.00 to repair.

 

The front fluid looked cleaner because it doesn't work nearly as hard (if at all) as the rear, depending on how you use the truck.

 

On rears that experience heavy torque loads you often set them up shallow, to allow any deflection to be handled.

The gears in my Nova are wearing very much like your pictures, and I am not worried.

 

X2 on running a pattern. That does look a little weird. I think you can download pictures of different normal and abnormal patterns from Richmond for comparison. Might also be a good idea to check the backlash.

 

thanks for additional replies. I'll add that truck has 58k so it is still under warranty. I intend to measure backlash with a friends dial calipers and share the photos with a local driveline shop. I'll share what I find.

Sven

 

Setting gears up shallow will not prevent ring gear deflection. Moreover, setting the pinion shallow would cause most of the loading to be put on the crown portion of the ring gear tooth.

Setting the pinion depth correctly would center the pattern between the root and the crown of the ring gear tooth and also between the heel and the toe of the ring gear tooth.

Setting the carrier bearing preloads correctly is what prevents ring gear deflection. Utilizing an inch/pounds recording torque wrench to measure Pinion Torque To Rotate(PTTR) and subtracting it from Total Torque To Rotate(TTTR) will determine the carrier bearing preload.

 

Your circled areas look like the sharp edges on the gears were machined and appears to be completely normal. Oh, nice pictures. I get so use to seeing fuzzy pictures posted. You did real good with those examples.