Lessons Learned from Lifting a 2021 JLUD

[HighCountryJLU]

I'm making this post in hopes that it will help some poor soul in a similar position in the future.

Everything about the Diesel variant of the JL seems to be weird or different. I set out to lift my 2021 Sport S Diesel with JLURD Diesel Springs and some TeraFlex Spacers and had a heck of a time finding information.

Here's the parts list of what was on my Jeep and what went on for reference:

• Original Front Springs (same on both sides): 68416582AA
• Original Rear Springs (same on both sides): 68253600AA
• Donor JLURD Front Springs (same on both sides): 68307622AD
• Donor JLURD Rear Springs (same on both sides): 68253601AA
• TeraFlex 1" Front Spacer Load Leveling Kit (two on each side, total of 2" each side): 1155100
• TeraFlex 0.5" Rear Load Level Kit (two on each side, total of 1" each side): 1155120
• Mopar Extended Front Lower Control Arms (same on both sides): 68322798AA
• Bilstein 5100 Extended Front Shocks (2-3" Lift): 33-292625
• Bilstein 5100 Extended Rear Shocks (0-1.5" Lift): 33-316321

The expected lift that you expect from swapping Rubicon springs onto a Sport is not a thing with the diesels. I got my springs from a donor with the same specs as my Sport (same engine, hard top, tow package, etc) so other than one being a Rubicon, things should mostly be apples-to-apples. Here's a picture of the two front springs together (Rubicon on the left, Stock on the right):

I didn't realize there was so little difference until after I had already done the rear, so I sadly don't have a picture of the rears together, but I suspect much of the same. I measured the fronts to be less than 3/16" difference in length when not compressed.

Before I started any of this, I had already put a heavy steel bumper and a winch on the front of the truck, so understand this isn't bone stock. Here's the measurements (tire to fender bend) for my situation:

• Front Left: 4.500" -> 7.000"
  • 2" of spacer and Rubicon springs
• Front Right: 4.375" -> 7.000"
  • 2" of spacer and Rubicon springs
• Rear Left: 6.000" -> 7.500"
  • 1" of spacer and Rubicon springs
• Rear Right: 6.125" -> 7.500"
  • 1" of spacer and Rubicon springs

Everything that I've read and seen says that the spacer lifts are true-to-size with lifts, meaning a 1" lift gives an actual 1" lift. If that's accurate, then I only got about 1/2" out of the Rubicon springs on both the front and rear - a far cry from the 1" - 1.5" most speak of when going from Sport to Rubicon springs on the gassers.

A few other random tidbits of information just for people searching and coming upon this thread:

• The bump stops on the front on the diesels are 1.375" longer than on non-diesels. I opted to add no additional bump stop here, as most of the posts I've read say people are adding lifts up front just to get some upward travel since they sit so low.
• The rear bump stops should be the same as the normal JLs. I still need to assess for adding bump stop there.
• The rear driver-side upper control arm frame-side bolt is completely inaccessible because of the fuel tank. I don't know if this is the same for the gassers, but short of dropping the tank, I don't see a way to touch it. I'm taking my chances (since it was only 1" added in the rear) with just leaving it as it was and praying it doesn't fail any faster.
• The extended front LCAs are totally worth it.

Hope this helps someone in the future.

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