OPDA recall says check engine number

[rockbottom]

I saw this in the “how to “ section
Mine is 2006 rubicon lj and has the S as the 8th number in the SN

I also saw to check the engine number, said it was on the block passenger side close ti firewall
I have yet to find it

Any ideas on where or how to confirm engine number or to determine if I have the upgraded OPDA

THANKS AHEAD

 

[OldBuzzard]

If you have an LDI Inc. sticker on your OPDA, it's an OEM one - but whether it's the early 2005 bad one, or the somewhat-better-but-not-fully-cromulent replacement late 2005 & 2006 one is unclear. My Crown OPDA came without a sticker.

 

[Infinite Toast]

"Stamped Engine Serial Number
The 4.0L engines generally have a stamped machined pad containing an engine sequence number.
On most 1997–2006 TJ Wranglers:

• Look on the passenger side of the block
• Just below the cylinder head deck surface
• Near the front of the engine, above the motor mount area

The stamping may be faint and covered by paint, grease, or rust."

https://jeepinside.com/jeep-6-cylinder-engine-block-casting-numbers/

S

 

[JKP]

All the LDI OEM ones are junk, no need to check any numbers. They all have a sealed upper bushing that will dry out and fail.

There were no factory upgrades, the recall was due to improperly hardened OPDA gears on 05s.

 

[sab]

All the LDI OEM ones are junk, no need to check any numbers. They all have a sealed upper bushing that will dry out and fail.

There were no factory upgrades, the recall was due to improperly hardened OPDA gears on 05s.

Attached is the notice that JKP mentions. Also, last year I dissected and compared the OEM OPDA to Crown's OPDA and found that there were definite improvements made by Crown to address the failures of the upper bearings in the OEM design. Here's the thread I created with that information:

Thread 'A Comparison of the OEM 05-06 OPDA to the Crown Aftermarket Version'

Nov 26, 2025

I recently decided I wanted an oil pump priming tool, and I figured the best way to make one would be to use a castaway OEM OPDA. I replaced the OEM one in my LJ with a Crown one at about 48,000 miles, and I saved the OEM as a spare. Since it has relatively low miles, I decided to look for another one to make this tool. After acquiring one, I set to work on making the tool, but before I did so, I decided to compare it to the Crown, to confirm if Crown really had improved the design.

I started by removing the covers off each unit. After removing the covers, I punched out the roll pins...

• sab
• Replies: 7
• Forum: TJ Resources

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[sab]

Also, if you look at Page 5 of the notice I posted above, you'll see that you don't even need to look at the engine number if you can still read the label on the OPDA. You just read the date code off the label:

And then use that to determine if your OPDA has the soft driven gear on it:

Note that there were only 68 OPDAs produced with soft gears, and that the repair performed was just to change the gear on the OPDA (and the cam, if that gear was damaged). They didn't change the entire assembly. As JKP stated in his post, all the OPDAs from Mopar are junk because they leave the upper bearing without lubrication and it will eventually fail. If you have an OEM OPDA (with the LDI label like below), it's best to install a Crown OPDA.

 

[rockbottom]

Thats all great history and bad engineering design.

All this information makes it a no brainer to replace the OPDA with the Crown OPDA
IM ORDERING MINE TODAY

I watched the U-tube that Chris posted
Looks straight forward

Is it necessary to get a mechanic to check the settings with the computer if I follow the “pin” procedure and dont get any codes

Lots of people seem to have issues after the install

Thanks to all for great feedback

 

[sab]

Is it necessary to get a mechanic to check the settings with the computer if I follow the “pin” procedure and dont get any codes

It is definitely wise to fine-tune the OPDA position (the "pin" procedure isn't usually good enough) to set Cam/Crank Diff as close to zero as possible and then perform the Cam/Crank ReLearn procedure. However, I don't know too many mechanics I would trust to understand it enough to get it right. Even Jeep dealers are hit and miss because these vehicles are 20 years old, so finding a mechanic at a dealership that worked on them is difficult. If you are unable to do it yourself following the many threads on this forum on the subject, it would be wise to make sure that whoever you pay to do it understands what they are doing. It ain't rocket science, but the level of misunderstanding out there is astounding.

 

[OldBuzzard]

I'm still looking for the OBDII codes where Chrysler stashed the Cam/Crank Difference data. I've looked through the mostly undocumented Mode 6 stuff, and I don't think it's there. I suspect it's in the totally undocumented Mode 22 stuff. Chrysler keeps that info locked away behind a very expensive paywall, and as far as I can find, nobody has leaked it. With that info I could build a cheap ($50) reader just for that single purpose.

 

[sab]

I'm still looking for the OBDII codes where Chrysler stashed the Cam/Crank Difference data. I've looked through the mostly undocumented Mode 6 stuff, and I don't think it's there. I suspect it's in the totally undocumented Mode 22 stuff. Chrysler keeps that info locked away behind a very expensive paywall, and as far as I can find, nobody has leaked it. With that info I could build a cheap ($50) reader just for that single purpose.

I'm no help on that. However, it seems that some of the Chinese scanner makers have cracked that code. There are several reports in threads here of people using cheaper scanners to read Cam/Crank Difference and Cam/Crank Learned PIDs, although they are not in units of degrees.

 

[Zorba]

Thats all great history and bad engineering design.

All this information makes it a no brainer to replace the OPDA with the Crown OPDA
IM ORDERING MINE TODAY

I watched the U-tube that Chris posted
Looks straight forward

Is it necessary to get a mechanic to check the settings with the computer if I follow the “pin” procedure and dont get any codes

Lots of people seem to have issues after the install

Thanks to all for great feedback

Watch videos, read threads. I didn't have any problems, but I may have just gotten lucky. If it helps, here's my particular experience, all detailed in a boring blow-by-blow:
https://www.doubleveil.net/jeep/twenty-eight.htm

 

[rockbottom]

Thanks again to all the shared information