Is this pinion gear usable?

[mysticclam]

I have this set of 4.56s for my 8.8 (richmond) but there is a small chip on the end of one tooth on the pinion. This is a used set and you can see that the chip is in an area where the black hasnt worn off. This makes me think is not a spot where the two gears contact anyway. You cant tell from the picture, but it is a very shallow chip, almost no depth at all so I dont know if i should just use it or get a new set.

 

[rookieshooter]

IMO, an accident waiting to happen. If you have to use it I would have it magnafluxed and debur the sharp edges. Those sharp edges = stress cracking. It's not that far from the worn part of the gear. When that one chiped gear meets the gear of the ring gear, stess goes thru the whole gear tooth and up to the crack which could lead to a catastrophic failure. Not to mention vibration problem. Junk it.

 

[mechanix]

I would have to disagree with rookie. I would say this it is fine. I would deburr around the chip and let it run. To install a 4.56+ gear set you have grind the ring gear anyway. So I can't see that this would hurt anything. Like you said it dosent even contact the ring gear at all.

In my eyes. Run it!!!

 

[sparky2263]

I'd de-burr it, put it in and take a good close look at the pattern. If it changes on that tooth, then you gotta junk it.

It's slightly risky, but I'd run it. Wouldn't put it in a customers vehicle though.

 

[Creager]

^^^ im with him

It all depends on how its sets up.

If it came out of the other guys differiential like that, then its probably fine.

Yes its in a spot that only gets used 1% of time, but if your gears are alighned to put more torque in that spot more then not... (competition patterns) you see where this is going. If it makes noise when are test it on the bench, i wouldnt use it.

the first 3/16" of the tooth doesnt make much contact anyway.

 

[mysticclam]

rookie, thats exactly what I was thinking, that the chip creates a place for new cracks to happen. I assume since its used and must have some wear on it that I cant get just a new pinion and have it mesh well.

 

[Creager]

There have been times where gear sets were missing teeth and still worked. The gear you have can work, esspecially if the proper care and time is taken to make it work. It probably doesnt even need to be deburred, its probably as smooth as marble; if its been ran like that already, its probably a non issue. If thats the case, may it be a ticking time bomb, may outlive everything else on your drivetrain.

Gears are only sold in sets, unless you got a spare 8.8 4.56 pinion gear lying around, its gonna be hard to find just a pinion.

 

[mysticclam]

Thats what I figured, and for the reason I said. They wear together. Install is just to expensive to do over. I think I will get another set.

 

[Creager]

Oh yeah, good call; definatly get a new set if you are paying someone else to install it.

Would it not be cheaper to have the shop install their own brand of gears? you probably can get away with a warentee and what not.

why not just buy a spare rear-end from the junkyard, and use this set to practice setting up gears? Then when it explodes put the spare underneith there and go out and buy a new set =)

 

[mysticclam]

hmmm, are you saying use these but install them myself in a different axle since they are already kind of toasted so i wont be out anything if i screw them up Then have the original axle regeared later if these blow up. I suppose If there was another 8.8 around cheap.

 

[Creager]

yep, exactly what im saying; swap to disks while yr at it =)

 

[Hotweels]

take a rotary tool to that tooth and smooth it over, start with some 80 grit and werk yer way to about 140 grit then buff it with a red scotch brite pad.... there is noting wrong with that gear set.... i have seen 1/4 and 1/2 teeth missing... sunday nite after trail run pull out broken teeth, blend in the sharp edges and run it monday till friday back and forth to work at 100kph on the hiway and never have a problem.... that is a very minor chip in a very large gear that makes 99% of it's contact some where else...

 

[mysticclam]

ok, how about second opinions

For a lark I decided to grind the chip smooth. So far this is what Ive got, seems like it would be ok if I hit it with finer grit and get it more polished like. What does everyone think.

 

[Hotweels]

yup look's good.... i would run it as is no worry's... but if it makes ya feel better switch to a lighter grit and polish it like a mirror....

 

[98 sport]

I'd run it, if that part of the pinion hits the ring gear you got more problems than that.

 

[mysticclam]

Been running that pinion and ring gear set for a week now. Its seems ok thus far. No noise at all.
Also, at 160,000 miles I'm amazed the original gearset looks brand new. A couple tiny tiny marks (pencil dot sized) at the big end of the pinion but it still looks sooooo new. Awesome.

 

[RockRanger]

I drove my old ranger 1200 miles with two full teeth missing off the pinion. Did you set them up yourself or have someone else?

 

[mysticclam]

A friend of a friend set them up. He drag races mustangs and works on all sorts of project cars. He seemed very knowledgeable about the 8.8, made sure that the gears didnt contact on the area I smoothed out. I still have to get the front done, ill probably pull the center section out and take it someplace, hopefully that will make it a little cheaper. Im tempted to get another center section take some time and try and do it myself. Either way I need to do it soon so I can have 4wd back.