How bad is my OPDA cam gear?

So a couple of weeks ago I got a P0344 Code and my LJ went into limp mode. Having previously replaced my OPDA with a Dorman unit about 10 years ago (but only 40,000 miles on the Dorman unit since then), I was aware of the OPDA issue. So I ordered a Crown OPDA and installed it last night. Unfortunately I think I waited to long. Because my cam gear looks pretty rough. Surprisingly the gears on the Dorman OPDA show minimal wear, but the cam gear looks pretty rough to my eyes. Bad enough I was afraid to start the Jeep after I finished the install.

So my question is basically, what do I do from here?

1) Can I run the Jeep with the new OPDA and check the codes and see how it goes. Or will this cause bigger issues?
2) Do I need to replace the cam shaft? How long do I have until it needs replacing?

NOTE: I used a bright LED when taking the picture so the gear may look slighly worse than it really is. But its noticably worn in an uneven apttern.

JKP said:

If the gear on the Dorman looks OK, I'd put it back in and run it till you get too much slop in the gears. No need to put a new OPDA gear on a worn cam.

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The problem that I see with that solution is that the cam was fine when I changed out the previous OPDA for the Dorman. So I think the Dorman was sticking and caused the wear on the cam. I wonder if the dorman gear was hardened more than the cam gear and the cam took all of the wear. Also I pulled the OPDA due to a code. So I have some concerns that I may already have too much slop in the gears.

My hope is that the new Crown OPDA will spin more freely and if I get the timing spot on I can still run it. But my biggest concern is if I am risking loosing my oil pump or something by running it with such a worn cam gear.

I got a P0344 Code.

I never spun the Dorman. I did noticed that it felt pretty free with the little movement it had with the lock pin in it. I'm going to look at things again tonight. I've read they can spin free without a load, but bind up with a side load. So I'll look it over a little better.

I'll get back to you with a picture and my other test on the Dorman unit.


Loosing the oil pump is my concern. Would I get a code again if the gear was that bad or would I just loose oil pressure and destroy the engine?

So spinning the old Dorman OPDA it spins relatively freely, but not consistently. As I spin it, I can feel it spin easily then get a little harder. Or if I start in a section that has more resistance, I will feel the resistance suddenly disappear and it will spin quicker with the same force.

Are there any distinguishing marks on the OEM sensor? I just realized my Dorman unit has a limited lifetime warranty. So I might see if I can get a replacement. But I don't want to give up my OEM sensor and I don't recall for sure which sensor I had on the Dorman.


Here you can see the Dorman gear has some wear but looks good. Its crazy how rough the cam gear looks in comparison. But I will acknowledge the cam has 130,000 miles vs 40,000 on the Dorman unit. But the cam appeared to have normal wear when I installed the Dorman.

So looking at the sensors I found some interesting things. It doesn't change that my cam gear is still really worn, but I've made some interesting observations.

First off the sensor that came out of my Dorman appears to have rubbed the timing wheel a little and the housing has a crack. Could that be the reason for my code? I thought the sensor was good because I checked it out with a multimeter before I pulled the OPDA and it checked out good.



Now for the other interesting things. Just for clarity, I have 2 used OPDAs on hand. The Dorman and I believe a Mopar one that had a bearing mod done to it by a Jeepforum member years ago when the OPDA issue was just starting to be known.

Going into my sensor research, I thought I had put my Mopar sensor into the Dorman unit, but looking at the two sensors I think I have been using the Dorman sensor for the last 10 years. I think you will see why I think this when you look at the picture below.

Looking at picture you will see that one sensor has a number on it. Searching the forum I found an old thread where someone was looking for a used Mopar sensor and the sensor they purchased has that same number. So assuming they got a Mopar sensor, the sensor with the number on the end should be the OEM Mopar sensor. Even though I thought I was using the Mopar sensor But even more interesting was looking at the other end. Looking into the plugs of each sensor, the sensor with the number on it also has the red pin base filling the entire back end of the plug. The other sensor just has the 3 pins and the black base doesn't make a flush connection with the other end of the plug. I'm not sure if this makes any difference for weather sealing or anything, but it seems like a relevant difference between plugs.









In then end, although this is all very interesting and educational, my cam gear is still really worn. So I still have to decide if I need to replace the camshaft or not. But I do look forward to hearing your thoughts on all of this.

sab said:

The red piece is a terminal lock. It's purpose is to keep the locking tabs from unlocking. It's a belt-and-suspenders thing.

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Both units have the red locking tabs. I was referring to the inside of the plug. You should see it in the pictures.

JKP said:

Either the cracked plastic allowed the sensor to move and hit the wheel, or the shaft is wobbling.

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Good points. That crack will tighten up as it slides into the OPDA. So it seems unlikely it moved unless it was not in all the way from new. So its possible the shaft is bent slightly. That might also explain why it didn't spin with even resistance all the way through its rotation.

Any other thoughts on that cam gear in the first post? Do I need a new cam ASAP or can I run it with that worn cam? I was thinking about driving it through the summer with that old cam and then replacing it this winter. But knowing myself, if it worked through the summer, I'd probably drive it for a couple summers before I got back to replacing the cam. (Its not a daily driver any more. Just a summer toy).