Why the 392 doesn't need Rubicon transfer case?

[roaniecowpony]

Yeah why the shop told him it wouldn't fit will remain a mystery we won't solve until @Sportacus and I eventually install his transfer case. If I remember correctly the shop told him the splines wouldn't line up?

I also had some interesting conversations with shops about a t-case swap. A lot said it couldn't be done, just flat out wouldn't do it or craziest convo I had was a local shop quoted me 5k to install and said it would take them a week.

Mine was actually in a shop for a week while they tried to install a t-case they found that they claimed was for a manual. They tried 2 different t-cases before giving up and putting my sport t-case back in. At least they did not charge me for any of that work.

In the end I did it in my driveway in a weekend. From start to finish I'd say for me it was 14ish hours of labor since I had no experience and took time checking the forum thread write up. Plus I broke off the heads on my driveshaft bolts which was a setback. With a shop, lift and power tools I would imagine it should be 5-6 hours of labor.

Shows that you did your research and know your capabilities. Glad you took this on. Not many DIY wrenchers have done as much as you.

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[E.O.D.]

I thought I remembered a video (maybe Lite Brite?) where they were on the Rubicon Trail and at the gathering at the end of the first day. I want to say they were talking with the famous Jeep guy that wears sandals/flip flops (like the Easter egg on your plastic cowl around the windshield wipers) about the T case. I dont remember exactly what was said, but my brain came away remembering that there was a prototype with the 4.1 but whoever had more say in the decision wanted something different than the other Wrangler Rubicons, maybe more akin to the Moab, and their voice was the one that made the decision.

Again, it might be mixing 2-3 memories, wrong content creators, and wrong POC, but I was something to that effect.

Edit: He was a journalist, Rick Pewe that wore the sandals. And maybe it was someone else (an actual engineer?) that made the comments.

 

[WXman]

I know the Hemi produces a ton of torque but Rubicon transfer case also gives you a slower 4Lo. What about that, 392 owners don't miss that? In my case, the Willys transfer case does just fine but I wish my 4Lo and 1st gear was super slow like the Rubicon. I can use Jeep's hill descent feature or whatever it is called but I love engine braking.
Or Jeep sees 392 as a high speed offroader? I thought Mohave was the desert runner.

My guess is they are using the clutch-based transfer case behind the 392 to protect the driveline. Those clutch-based cases are garbage and slip so much that they overheat at the first sign of tough terrain, so it acts as a great fused link to protect the driveline from that monster torque being delivered.

 

[swampflyer]

I believe in the above statement but also that the average buyer does not know how to handle that much power, probably saw the future of somebody's teenager misbehaving badly.

 

[roaniecowpony]

I would guess that an Atlas or Rubicon type T-case, with the M210/M220 axles would trash the rear axle in short order on the street in 2wd, if full throttle launches and runs were a regular thing.

 

[Zandcwhite]

I would guess that an Atlas or Rubicon type T-case, with the M210/M220 axles would trash the rear axle in short order on the street in 2wd, if full throttle launches and runs were a regular thing.

With ATs or MTs I don't think you'd get enough traction to cause damage. Full throttle 2wd launches would just be tire smoke which isn't nearly as hard on the shafts as what we subject them to bound up in the rocks in moab or on the rubicon etc. while aired down.

 

[Sftdyna0326$]

No, it's a sincere question. 392 is so freaking loaded, but why no Rubicon transfer case? Did Jeep fear that 392 owners who love the Hemi would be annoyed by the super slow 4Lo? I am saying that because I have a diesel Wrangler friend, and he hates his Rubicon transfer case, in fact he wants to swap it with mine. He says his Wrangler is a diesel and he doesn't care about the Rubicon transfer case

I always thought it was very easy to understand!! Giving some of us the ability to have 2wd would increase warranty
Claims 10 fold! You would break everything from the transfer case back! Can you imagine having a 35" tire and wheel package tapping 100lbs x2 being spun violently then stopped in some cases so hard without breaking things??? Then having the transfer case with that super low gearing withstanding the kind of punishment we see while rock crawling with almost 500 ftlbs of
Torque?? Its not only clearly understood but should be appreciated especially once our drivetrain warranty expires! And honestly the only big negative for those of us that really run our jeeps off-road hard is the reduced engine braking with the Rubicon case which
is HUGE !!!!!

 

[Deen]

I guess I'm different. I'm considering an atlas t-case in the future with 5 to 1 gears for 4LO. I want the Jeep to go up the steepest incline in first gear with no gas pedal needed.

Sounds like my '21 JLUR diesel with 4:1 t-case and 4.88's. Full 442 ft lbs at 1,700 rpm. So, basically same torque as the 392 but much lower RPM. It always starts in 2nd gear when in 4L.

 

[roaniecowpony]

Sounds like my '21 JLUR diesel with 4:1 t-case and 4.88's. Full 442 ft lbs at 1,700 rpm. So, basically same torque as the 392 but much lower RPM. It always starts in 2nd gear when in 4L.

My 3.6 in 4 Lo (4:1) also takes off in 2nd when in Drive. I think my final drive ratio in 1st gear-4 Lo, is 90:1 reduction.

 

[Sftdyna0326$]

I would guess that an Atlas or Rubicon type T-case, with the M210/M220 axles would trash the rear axle in short order on the street in 2wd, if full throttle launches and runs were a regular thing.

ABSOLUTELY!!!!!!!
My wife's 392 would break everything if it had the Rubi case, especially in low range!!
Our friends 392 had the torque management turned off with a nolimits programer and in off road mode his truck launches so hard he jumps ahead of us by two full car lengths! When he had 37's and forced 2wd he blew one driveshaft and snapped an axle! He was lucky he had a great dealer up here in Long island because they covered it!
He is the type of driver jeep was worried about!

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