Aluminum knuckle failure

[Chocolate Thunder]

The aluminum knuckle - anyone know if it's cast or forged?

That is cast aluminum.

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[BradyW]

I thought the diesels had the same cast iron knuckles as the gladiators. Was that updated somewhere mid stream or am I mistaken?

Mine are magnetic, take a magnet to yours and it’ll tell you what is on your Jeep specifically. Seems like Jeep sometimes switches things out on the assembly line based on parts availability. Like 2022 392’s getting the old aluminum oil pan that gets the drain plug ripped off even though they had fixed that for late 2021 models.

 

[Chocolate Thunder]

Each side. LOL. They sell them as a set for around $600 with a coupon code.

Wait, WHAT? I have been scouring the Internet trying to find them for cheaper than $790 for a couple of weeks. Care to share that code?

 

[OldBlue]

Cast aluminum. Wonder if anyone makes forged ones... Be a he!! of a lot stronger.

 

[Rangemaster]

Each side. LOL. They sell them as a set for around $600 with a coupon code.

Who did you get yours from?

 

[BDinTX]

Mine are magnetic, take a magnet to yours and it’ll tell you what is on your Jeep specifically. Seems like Jeep sometimes switches things out on the assembly line based on parts availability. Like 2022 392’s getting the old aluminum oil pan that gets the drain plug ripped off even though they had fixed that for late 2021 models.

Yeah they’re aluminum. I’ll have to come up with a different plan since hydros are now off the table…

 

[Willycon]

Just saw this.

In the vid, the owner said, "I'm new to off-roading, the front wasn't locked in and it started wheel hopping". Pretty sure thats your cause.

 

[OBJLU]

Who did you get yours from?

Yeah lol where p

 

[roaniecowpony]

Nodular cast iron is about 40-50% stronger in tension than aluminum for the same cross section, depending on which commonly used alloy for these components. But making a direct strength comparison of a finished part is really difficult. Usually, the aluminum part has greater cross section to make up for lower strength. Failures like this are rarely a pure tension failure. So, would a cast iron knuckle have failed in this instance or not? That would take a pretty significant engineering analysis to know for sure. But my bet is the JL cast iron knuckle is stronger than the aluminum knuckle and that is the reason for it being specified for the 392.

If anyone is interested, there has been a price drop on the factory cast iron knuckles in the online sellers. They're still not below the Reid Racing knuckles for the JL. But it's closer.

 

[19 JLUR Bright Whit3]

Who did you get yours from?

My apologies. I fat figured the keyboard. I meant to type "around $700 with coupon code" (Edited).

I purchased them from Poly Performance. I didnt get charged sales tax or shipping. I used code NL10.

Item​ Qty​ Description​ Amount​ DBP-JL001 1 Reid Racing Jeep JL Heavy Duty Steering Knuckles (Pair) $785.00 Discount ($78.50) Tax $0.00 Total $706.50

 

[19 JLUR Bright Whit3]

Wait, WHAT? I have been scouring the Internet trying to find them for cheaper than $790 for a couple of weeks. Care to share that code?

My apologies. I fat figured the keyboard. I meant to type "around $700 with coupon code" (Edited).

I purchased them from Poly Performance. I didnt get charged sales tax or shipping. I used code NL10.

Item Qty Description Amount DBP-JL001 1 Reid Racing Jeep JL Heavy Duty Steering Knuckles (Pair) $785.00 Discount ($78.50) Tax $0.00 Total $706.50

 

[19 JLUR Bright Whit3]

In the vid, the owner said, "I'm new to off-roading, the front wasn't locked in and it started wheel hopping". Pretty sure thats your cause.

LOL. He sure has a lot of trail badges for a Newbie.

 

[CarbonSteel]

Do the Mopar steel knuckles have a part number yet?

68477358AA - Front Knuckle, Right
68477359AA - Front Knuckle, Left

10K+ miles on mine thus far with no issues. I bought a set of Reid's and sold them, I did not like the orange coating. Reid's were $650 to the door from Northridge last May.

 

[sourdough]

Bigger than spec'd tires and wheels are the issue. Folks in the know that wheel big rubber have been swapping to D60 axles for close to forty years. Doing anything less is kicking the breakage can down the road. JL D44's have been beefed up some but weakened with the FAD housing, aluminum knuckles and weak Track Bar attachment points.

 

[roaniecowpony]

Cast aluminum. Wonder if anyone makes forged ones... Be a he!! of a lot stronger.

I thought I had looked at them before and they had looked forged to me. So, I looked again this morning. Sure look forged to me. The fidelity of the lettering and foundry timer is too fine to be sand cast and the parting line is wider than I'd observed in permanent mold low pressure casting. My background includes manufacturing engineering with a focus in machining, not forging or casting. But I've seen a lot of both.

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