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Discussion Starter · #1 ·
After past problem upon purchasing the jeep and rebuilding the engine (never touched the cam) it's been about 10k miles. I was driving down the road and lost oil pressure and long story short after dropping oil panel and finding metal shavings, I checked main and rod bearing all were good. I then discovered the teeth for the oil pump were sheared off. Has anyone ever heard of this as they are literally gone. What else should I look into replacing and with what upgrades so this doesn't continue to happen.
 

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The 05-06 4.0 OPDA is a crappy design that is known to fail

Google laughing monkey

Bad part is it can both damage engine from low oil pressure and damage cam gear when OPDA fails


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What Digger says.



If you are “lucky” you get the laughing monkey warning sound but others will fail without warning. Usually the OPDA shaft seizes causing the gear to fail. Be sure to pull the OPDA & see if the shaft spins freely. If not, add that to the list of replacement parts needed.
 

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Discussion Starter · #4 ·
I have decided to just restart and purchase a remanufactured long block. How can I prevent this same problem from happening to my new motor do I have to get a certain year or just a certain opda? What are my options to never have this problem again.
 

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The pre 2000 TJ 4.0s don't use an OPDA

The 2000-2004 OPDA is trouble free design

But the 05-06 4.0 computer will only run with the 05-06 OPDA

The dorman 05-06 OPDA is more reliable then the OEM but keep using the OEM sensor on top of the dorman OPDA as the OEM sensor is more reliable

The only sure solution is avoid the 05-06 TJ as both transmissions are a crap shoot and there is a list of other design flaws unique to the 05-06 half assed hold over design with the tighter emissions on an orphan engine destined to be abandoned in the JK and already phased off all other jeep platforms before the 05 emissions rules took effect


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Happened to me at 190K on my 06' Rubi. I replaced the original opda with a Dorman. 8k later the cam gear sheared off. I had the motor replaced with a Jasper reman. Unfortunately the new opda is a Dorman....it has to stay until the warranty runs out.
 

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Did you check to see if the shaft spun freely on the old one? That should tell you what caused the failure. If the shaft was binding, the drag can cause the gear to fail if the shaft locks up. If it spins freely, the cause is more likely a bad gear, maybe of poor quality material. Was the failed one a Crown or Dorman?


On the new engine…

I would recommend using a high zinc oil like Valvoline ZR-1 10-30 or a zinc additive to a good quality oil, lubing the (new) OPDA gear with assembly lube before installation & even consider pre lubing the top bushing. That would require removing the shaft but a light coating of assembly lube might be helpful keeping the top bushing lubricated until the engine oil work its way up there. Especially if the shaft was binding on the old one.
 

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Discussion Starter · #8 ·
Did you check to see if the shaft spun freely on the old one? That should tell you what caused the failure. If the shaft was binding, the drag can cause the gear to fail if the shaft locks up. If it spins freely, the cause is more likely a bad gear, maybe of poor quality material. Was the failed one a Crown or Dorman?


On the new engine?

I would recommend using a high zinc oil like Valvoline ZR-1 10-30 or a zinc additive to a good quality oil, lubing the (new) OPDA gear with assembly lube before installation & even consider pre lubing the top bushing. That would require removing the shaft but a light coating of assembly lube might be helpful keeping the top bushing lubricated until the engine oil work its way up there. Especially if the shaft was binding on the old one.
So I checked it out after pulling the engine today and it was a dorman the unit when through a complete failure with almost a quarter inch of play up and down in the OPDA like the whole shaft would pop in and out. It had a little resistance but it was definitely a poor design failure
 

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I can attest to the 05-06 transmissions being junk. I wish I had known what I was getting myself into, before buying an '05.

As for the OPDA being bad, my understanding is that Crown corrected the flaws in the design. If you Google around, you'll find threads on this. Buy one of theirs, but save your old camshaft position sensor. Mine was bad and someone told me the Crown sensors included with the OPDA were junk, but my experience could have been a fluke.
 
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