Yeah I have to agree with jkitterman-the wear pattern on the gears are nowhere near the machine marks that you highlighted in your pics. Those marks you highlighted are (1) away from the marked areas showing gear mesh, (2) have sharp, demarcated edges indicating machining-irregular wear or damage doesn't produce sharp edges like that, and (3) are at the edge of the ring gear-nowhere near where the pinion contacts (as shown by the pattern on the ring gear). I think everyone above is correct-unless you hear noise, leave it alone.

Trust me when I say casting "defects" can produce a lot of strange looking things on machined parts. The thing to remember is that just because a part has a casting defect DOESN'T mean that it's out of tolerance or not usable-as long as the defect doesn't involve areas of importance. If you want a great example, look at any of the cast (or, for that matter, forged) cranks from any old mopar big block-lots of defects on the crank counterweights, but the journals were machined true. Once the factory balanced the crank, the "defects" didn't make a squat bit of difference.

Leave your gears alone If the only reason you're staring at those gears is to change the diff oil, and the only reason you're changing the oil is because you're at 15K on it (and not because they're making noise), then your diff is just fine.

 

In a perfect world...

 

Tell you what, when you have gone through umpteen sets of R&P on a heavy, high torque car, you learn things.

Perhaps not so much ring gear deflection, but high torque WILL suck the pinion back. I ended up about .002 shallow for the best combination of pattern, noise, and R&P life on my car.

 

X2

stupidtooshortrule

 

patdaly is talking about how we're seeing 2, 3 or more times the power through some of these gearsets than the designers ever intended. Even the strongest gears set up perfectly, steel-on-steel will only take so much....

OTOH, you can have a worn out gearset with sawdust in the oil whining away for years behind a tired 4-banger.

In a perfect world, I'd have titanium alloy gears with NASA-grade bearings and lubricants that could stand up to any tuner stack with dual CP3s and the biggest injectors they make pounding them all day. Then I woke up...

 

Looks like the pinion is not set deep enough. Like the others have said, if its not howling dont mess with it. If you adjust anything you will be buying new gears.

 

Thanks for additional answers. Consensus is leave it alone so I will. To measure backlash or pinion depth seems to require some dismantling which I won't try till warranty expires. When I first purchased truck there was no play in the driveline. I would expect a little, but I think it now excessive. So, whether this be too much backlash or lack of pinion depth, could this represent the majority of play in the drivetrain ? If so, I would consider buying replacement gearset at 70k. Comments ?

Sven

 

Actually, you can check the backlash and pattern without dismantling anything other than taking the differential cover off.

To check the backlash just set up a dial indicator on a ring gear tooth and rock the differntial back and forth. Take the reading to see how much play there is when your rock it back and forth.

As far as checking the pattern just jack up the rear end, paint about 5 ring gear teeth, and turn the differential one revolution in each direction. Then match the pattern up to a chart that has gear contact patterns such as this:
http://www.yukongear.com/Downloads/T...structions.pdf

 

How much play do you have there at the back of the driveshaft? What is recommended? I replaced my seal there today and noticed an excessive amount of play.

Jared

 

The backlash on used R&P should be less than .010". There shouldn't be any end play.

 

Aside: Those are really nice pics!!! What camera, lens, focal length & f-stop did you use? What kind of lighting?

 

carefulll what you read, and what patterns you look at!
factory gears are cut much diferently than aftermarket and setup is nowheres near the same!
when some one said .010" b/l is ok on used, used aftermarket yes, used oem , no.
latemodel gears set up tight! ie: .002-.003 b/l, older oem and aftermarket are in the .006-.010 range.

gota love internet based misinformation based on oldshool technology.

 

The AAM TracRite if worked much leaves fine metal on the magnet and in the bottom of the hog head. It's a good idea to change the fluid often.
Billy

 

The Dodge Factory Service Manual calls for a backlash setting of .005" to .007" when setting up factory(AAM) gears in 2003 and up Dodge 2500/3500 trucks. If you were to set up AAM gears used in the 2003 and up Dodge 2500/3500 at .002" backlash you may overheat and ruin the gears as .002 is out of the specification and would not allow a thick enough film of gear oil to lubricate the gear teeth.

Weather the gears are aftermarket gears or factory gears has no bearing on the backlash setting; however, it has everything to do with the manufacturing process involved.

For example, the gears manufactured by AAM(OEM) for our trucks call for a .005 to .007 backlash setting because they are manufactured using a two-cut design that allows a tighter backlash specification. Gears manufactured by US Gear(aftermarket) for our trucks call for a .008 to .012 backlash seting because they are manufactured using a five-cut design which requires a looser backlash specification.

There are not too many gear contact pattern charts for the two-cut design which is why I referred to the Yukon website. The ideal contact pattern for the two-cut design is slightly different than the five-cut design. The ideal contact pattern will still be centered heel to toe and root to crown, but the contact pattern will appear slanted or "biased" going diagonally across the tooth.

Below are two ideal contact patterns with a two-cut gears:





Below is an ideal contact pattern with a five-cut gear:

 

Since it's not on the wearing surface most likely done to remove rough edges during assembly by AA. If no metal particles on magnet I wouldn't worry about it.