2021 40” Rubicon Diesel Build

40”JLURD

Well-Known Member
First Name
Ross
Joined
Aug 20, 2020
Messages
532
Reaction score
386
Location
Southern California
Vehicle(s)
2021 JL Unlimited Rubicon Diesel
Occupation
Bad Mother Fucker
Hi Guys,

This is my first post here and I wanted to start by saying thank you to all of you for all the great info you’ve put up here on the website. I am an experienced wheeler but all the review’s, install guides, and pictures of all your Jeeps have made it possible for me to do my entire Jeep build on paper and fully price it out before even ordering my Jeep!!! So thank you all very much for your contributions and I will be sure to do my part and share my experiences as well. Especially with this new diesel motor, which the aftermarket is still catching up to.

Now that I got that outta the way, onto the build!

I ordered my 2021 Jeep Rubicon Unlimited Diesel 2 days ago on August 19th 2020. (Ssshhhhh don’t tell the wife she doesn’t know yet lol) Long story short I wanted the Granite Crystal Metallic paint, tan leather seat package, BLACK hardtop (why pay $1,000 extra to have it painted) and BLACK fenders (because I’m going to replace them, I’ll be selling them so let me know if you’re interested) Also just about every other goodie. Had my dealership do a search and no such Jeep exists in the entire country at this time! Apparently the tan seats are a very rare option. So we custom built one and I placed my order with the Jeep factory ...

The lead time I was quoted was 6 to 10 weeks so we shall see how soon I get it with all this craziness going on in the world.





Advertisement

 
OP
40”JLURD

40”JLURD

Well-Known Member
First Name
Ross
Joined
Aug 20, 2020
Messages
532
Reaction score
386
Location
Southern California
Vehicle(s)
2021 JL Unlimited Rubicon Diesel
Occupation
Bad Mother Fucker
  • Thread starter
  • Thread Starter
  • #2
Are you keeping the factory axles?
Unfortunately yes I am keeping the factory axles... for now.

Dynatrac, or Currie 60’s would be great but the budget just isn’t there for them right now with buying the Jeep and all the other mods already planned.

Before everyone tells me how I’m going to break the factory axles while wheeling with the 40’s; here’s the plan with them.

Probably everyone knows that the new AdvanTEK M210 & M220 Dana 44 axle housings in the JL are stronger than previous genergenerations were. So that’s my starting point.

I’m also going to keep the factory e lockers which will save money and the factory locker switches which is nice since they are already there. It would be a shame to make it non functional with aftermarket lockers IMHO. Someone should make a mod to use that factory switch with aftermarket lockers.

Then I will re-gear to 4.88, upgrade the front to RCV 1 piece axle shafts and eliminate the FAD with a block off plate. Also while it is all apart to get gears and shafts I will have the builder put on a Artec Industries APEX Front Axle Truss & Inner C Gussets for added strength.

For the rear basically the same Artec Industries APEX Rear Axle Truss while it’s apart. To get gears and RCV axle shafts.

Motobilt Diff armor to put the cherry on top of both axles, and probably the MC rear diff skid.

If I missed anything please feel free to chime in.
 
OP
40”JLURD

40”JLURD

Well-Known Member
First Name
Ross
Joined
Aug 20, 2020
Messages
532
Reaction score
386
Location
Southern California
Vehicle(s)
2021 JL Unlimited Rubicon Diesel
Occupation
Bad Mother Fucker
  • Thread starter
  • Thread Starter
  • #3
All depends on your uses. I'd be really cautious pushing 40's on the D44, even with RCVs.
I love rock crawling and want to be able to run any trail I wish...

probably nothing higher than an 8/10 though
 
OP
40”JLURD

40”JLURD

Well-Known Member
First Name
Ross
Joined
Aug 20, 2020
Messages
532
Reaction score
386
Location
Southern California
Vehicle(s)
2021 JL Unlimited Rubicon Diesel
Occupation
Bad Mother Fucker
  • Thread starter
  • Thread Starter
  • #4
I know 60’s is the proper setup or a 60/80 but all the above axle mods are only about $5,400... leaves a LONG way to go before stepping up to built curries or dynatrack...

Maybe I can get one of them to sponsor me lol
 

Stormin’ Moorman

Well-Known Member
First Name
Michael
Joined
Mar 11, 2019
Messages
1,486
Reaction score
5,308
Location
Georgia
Vehicle(s)
2019 JLUR
Occupation
Forester
Vehicle Showcase
1
Unfortunately yes I am keeping the factory axles... for now.

Dynatrac, or Currie 60’s would be great but the budget just isn’t there for them right now with buying the Jeep and all the other mods already planned.

Before everyone tells me how I’m going to break the factory axles while wheeling with the 40’s; here’s the plan with them.

Probably everyone knows that the new AdvanTEK M210 & M220 Dana 44 axle housings in the JL are stronger than previous genergenerations were. So that’s my starting point.

I’m also going to keep the factory e lockers which will save money and the factory locker switches which is nice since they are already there. It would be a shame to make it non functional with aftermarket lockers IMHO. Someone should make a mod to use that factory switch with aftermarket lockers.

Then I will re-gear to 4.88, upgrade the front to RCV 1 piece axle shafts and eliminate the FAD with a block off plate. Also while it is all apart to get gears and shafts I will have the builder put on a Artec Industries APEX Front Axle Truss & Inner C Gussets for added strength.

For the rear basically the same Artec Industries APEX Rear Axle Truss while it’s apart. To get gears and RCV axle shafts.

Motobilt Diff armor to put the cherry on top of both axles, and probably the MC rear diff skid.

If I missed anything please feel free to chime in.
So you're thinking that 4.88 with 40s will be adequate with the diesel? Just wondering
 
OP
40”JLURD

40”JLURD

Well-Known Member
First Name
Ross
Joined
Aug 20, 2020
Messages
532
Reaction score
386
Location
Southern California
Vehicle(s)
2021 JL Unlimited Rubicon Diesel
Occupation
Bad Mother Fucker
  • Thread starter
  • Thread Starter
  • #6
So you're thinking that 4.88 with 40s will be adequate with the diesel? Just wondering
Going by gear ratio charts to keep it at factory rpm would be right at a 4.56 with the diesel. However the builder I’m going to use said the factory is under gearing the diesels a little (3.73) and he has already built a couple on 40’s. He suggested going to 4.88 with the 40’s on the diesel and since he’s already done a couple and driven them I’m not one to argue.

Also there was another member on here, can’t remember who; that has a diesel and went to 4.56 with 37’s then switched to 40’s.

He said the Jeep felt perfect with 37’s and 4.56’s and the 40’s were a little much. He wished he had gone 4.88. Which aligns exactly with what my builder suggested.
 
OP
40”JLURD

40”JLURD

Well-Known Member
First Name
Ross
Joined
Aug 20, 2020
Messages
532
Reaction score
386
Location
Southern California
Vehicle(s)
2021 JL Unlimited Rubicon Diesel
Occupation
Bad Mother Fucker
  • Thread starter
  • Thread Starter
  • #7
All depends on your uses. I'd be really cautious pushing 40's on the D44, even with RCVs.
What do you think the weak link in this setup would be?

The RCV’s are guaranteed not to break with up to a 40” tire with a lifetime warranty.

My builder will also warranty the work if I buy them through him and handle any warranty claims. Although that still won’t help get me out the middle of a gnarly rock crawling trail with a broken axle and then all the way to his shop either.

With the 1 Piece RCV’s, Axle truss, C gussets, and FAD elimination what is the weak point that’s left?
 
OP
40”JLURD

40”JLURD

Well-Known Member
First Name
Ross
Joined
Aug 20, 2020
Messages
532
Reaction score
386
Location
Southern California
Vehicle(s)
2021 JL Unlimited Rubicon Diesel
Occupation
Bad Mother Fucker
  • Thread starter
  • Thread Starter
  • #8
If you're spending that kind of coin (for Dynatrac or Currie)...there are far better options....like Spider 9s with Gearworks 10.5" or Tru-Hi 9 centers or even a Torq 14.
Any suggestions for something maybe closer to $10k which would swap the front and rear? The whole reason I wanted to keep the stock ones for now was $15 - $18k is just outrageously expensive on top of everything else
 
OP
40”JLURD

40”JLURD

Well-Known Member
First Name
Ross
Joined
Aug 20, 2020
Messages
532
Reaction score
386
Location
Southern California
Vehicle(s)
2021 JL Unlimited Rubicon Diesel
Occupation
Bad Mother Fucker
  • Thread starter
  • Thread Starter
  • #9
Boneyard 60/14B....keep them 8 lug, go simple in terms of the lockers....spend the money on front RCVs, flanged yokes, good aftermarket knuckles/steering arms and hydro assist (or full hydro if you're comfortable with that).

You can literally build a 14B for $1500 with gears, a locker and discs. $8500 for the front 60 might be a stretch, mainly b/c of the steering...but it's worth its weight in gold to be able to actually hold a line and with 40's and factory steering, you're going to HATE life in the rocks.
I already had about $800 budgeted for steering, add that to the $3000 selling the stock axles and I’m a lot closer!

As far as steering the plan was only to keep it stock till PSC comes out with a kit for the diesel. Right now they don’t have one that I’m aware of. I was gonna go Redneck Ram but builder suggested against it and said just wait till the PSC comes out.

You’ve really got my GEARS TURNING on thinking about axle swaps now... damn you.... lol j/k thanks for the great ideas
 
OP
40”JLURD

40”JLURD

Well-Known Member
First Name
Ross
Joined
Aug 20, 2020
Messages
532
Reaction score
386
Location
Southern California
Vehicle(s)
2021 JL Unlimited Rubicon Diesel
Occupation
Bad Mother Fucker
  • Thread starter
  • Thread Starter
  • #10
Oh, and you can probably offset at least $3K for your factory D44 takeoffs from the Rubicon.
It’s gonna see a LOT of street and highway driving, so I’ll probably need to go for an ARB... maybe need a little more than $3k for the factory D44 takeoffs lol
 
OP
40”JLURD

40”JLURD

Well-Known Member
First Name
Ross
Joined
Aug 20, 2020
Messages
532
Reaction score
386
Location
Southern California
Vehicle(s)
2021 JL Unlimited Rubicon Diesel
Occupation
Bad Mother Fucker
  • Thread starter
  • Thread Starter
  • #12

guarnibl

Well-Known Member
Joined
Apr 3, 2017
Messages
981
Reaction score
532
Location
Phoenix
Vehicle(s)
2021 Jeep Gladiator Rubicon Diesel, 2021 Jeep Wrangler Rubicon (on order), 2009 Jeep Wrangler Rubicon (crawler)
Any suggestions for something maybe closer to $10k which would swap the front and rear? The whole reason I wanted to keep the stock ones for now was $15 - $18k is just outrageously expensive on top of everything else
You're probably more like $12k after selling axles. Less after you consider what you're going to spend re-gearing etc.

Sorry but if you wheel a lot with 40's (i.e., you need 40's to get through the trail) you're gonna have a bad fuckin' time and then you can't even sell those axles after the fact for more than you would have just sold them to begin with. Just put 37's on it for now (and don't touch the axles) and buy axles when the budget allows.

Also I've literally watched an RCV break on the trail.
 

ChattVol

Well-Known Member
Joined
Jun 29, 2018
Messages
2,445
Reaction score
2,562
Location
Tennessee
Vehicle(s)
JLU 4 door
Any suggestions for something maybe closer to $10k which would swap the front and rear? The whole reason I wanted to keep the stock ones for now was $15 - $18k is just outrageously expensive on top of everything else
I love rock crawling and want to be able to run any trail I wish...

probably nothing higher than an 8/10 though
A pretty good driver and moderately built rubicon jlu on 37s can do trails rated up to 8/10. If you dont have the $ for d60s and want to run those trails, why not save the $5400 you would dump into stock d44s and roll with stock axles and 37s? I'd steer clear of running 40s on stock axles if $ is tight bc you're opening up a can of worms that will likely lead to hydro assist, upgrading brakes, ball joints, broken shafts, broken R&P + all the axle mods you listed. In the long run, I imagine you'll spend more dumping the $5400 into the stock axles and then going to d60s down the road and sell your modded d44 axles.

I was wheelin this week with my friend in a diesel jlu sport on stock d44s, 3.5" lift, 38s on beadlocks with no lockers. We did a few tougher lines that would prob be rated 6-7 and the diesel made it without lockers with sport t-case. I imagine it would have walked up if he was locked up and used more momentum He also ran Golden Spike, Hells Gate and Cliffhanger at Moab with this setup.
 

Advertisement




PSC Motorsports
 



Advertisement
Top