diagnosing gear wear

[LittleHorse]

Guys,

Hoping someone whose got extensive transmission experience (AllanD!) can look at a gear and tell me what would cause this type of wear.

It's a distributor/oil pump drive gear on a non-RBV.

It's well covered in oil so I don't think it's lubrication.

Could it be poor tooth profile design, poor machining tolerance or substandard materials?

If this gear is worn this way and I replace it, is the camshaft gear it mates to likely worn and will it just wear the new driven gear the same way?

I've got my fingers crossed that the other gear is significantly harder, wore down the imperfections on this one and additional wear has ceased. No traces of metal in my oil so maybe it's been this way for a while?

 

[mentalbreakdown00]

I've seen this on a few dodge distributors, correct me if i'm wrong on the make

 

[LittleHorse]

I've seen this on a few dodge distributors, correct me if i'm wrong on the make

pretty close, Jeep. Apparently it's an issue with late 2004 to 2006 Wranglers with 4.0. Technically it's not a "distributor" per se, it's actually an oil pump drive assembly with camshaft locator, basically it looks like a distributor but instead of plug wires coming out of it, it's got a toothed wheel with a camshaft position sensor on it.

There's a TSB on it but no recall. Chryslers response to it has varied from a teardown and replacement of camshaft along with the OPDA, to just replacement of the OPDA or retrofit with another gear that involves redrilling a new locator hole for the roll pin.

At this stage I think just replacing the OPDA or the gear would be ok, but I've seen some (with much fewer miles than mine, even) where it was completely trashed.

 

[mentalbreakdown00]

D/C/J it's all the same, we have put 2 in my buddys truck, next time we will probably have to put a cam in it, and dodge won't do anything for him. I've done several in my shop...

 

[LittleHorse]

The part number for the OPDA is still the same but it's now got a Rev E on it in the serial number instead of a Rev B like mine. Haven't figured out whether the E includes a change in that gear.

I'm probably gonna start with taking it to Chrysler (still under the 7 yr/70k mile powertrain warranty) and see what they say. I'll try to get a new camshaft put in with a new OPDA or the retrofitted gear.

If they won't do the camshaft I'll probably just change to the older gear and monitor the wear on it.

 

[LittleHorse]

ok, apparently the Rev E has the same problem.

Replacement assemblies are on indefinite backorder from Chrysler, with about 250 units on the backorder list. Those with the backorders have been told around end of September.

Apparently the supplier went under so they're having to get new units made by someone else. Hopefully the new units will include a different gear - maybe the one from the pre-04 models that doesn't have wear issues.

This has gone to the extent of people performing Rockwell hardness tests on the gears to compare them, and found the hardness of the new gear to be identical to the old, so it's not a soft gear issue. The blocks are the same so there shouldn't be an alignment issue, so I'm leaning toward an actual gear design issue. Worm gears are among the most sensitive gear types to tooth profile, because the contact between the gears is friction instead of impact.

 

[mentalbreakdown00]

ell, my buddys completely stripped this morning, looks like a tear down and a cam and all is gonna have to go in...