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Swapping Rubicon T-case vs. re-gearing Sport axles

Rodeoflyer

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I can tell you, I was smelling trans fluid cooking from 2 vehicles back.. the guy behind them said to go into 4 low and that helped but they were still like a 3.73 rear axle and a 2.73:1 transfer case with what like a 2.80 1st gear in the auto.. I mean it's gonna cook your trans.
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6.2Blazer

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I can tell you, I was smelling trans fluid cooking from 2 vehicles back.. the guy behind them said to go into 4 low and that helped but they were still like a 3.73 rear axle and a 2.73:1 transfer case with what like a 2.80 1st gear in the auto.. I mean it's gonna cook your trans.
Isn't first gear in the 8 speed auto 4.7:1, and 2nd gear is even lower than the 2.80 quote above?
But in any case, the post above seems to state they weren't even in 4 low. If that is the case it's not a problem with the automatic transmission but a problem with somebody not knowing how to drive. Go run a trail in high range with a manual transmission rig and see how long the clutch lasts before you fry it!
 

Rodeoflyer

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If that is the case it's not a problem with the automatic transmission but a problem with somebody not knowing how to drive. Go run a trail in high range with a manual transmission rig and see how long the clutch lasts before you fry it!
That's true, it was an issue with the drivers. We kept telling him to drop into 4lo...

and yeah, the clutch wouldn't last long in 4hi either :)
 

word302

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Isn't first gear in the 8 speed auto 4.7:1, and 2nd gear is even lower than the 2.80 quote above?
But in any case, the post above seems to state they weren't even in 4 low. If that is the case it's not a problem with the automatic transmission but a problem with somebody not knowing how to drive. Go run a trail in high range with a manual transmission rig and see how long the clutch lasts before you fry it!
Unless you’re shifting a bunch mid-obstacle low range vs high range makes no difference in a manual. Sometimes wheel speed matters.
 

6.2Blazer

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Unless you’re shifting a bunch mid-obstacle low range vs high range makes no difference in a manual. Sometimes wheel speed matters.
Huh? Maybe we are talking about different things? I'm talking about shifting the transfer case into 4 low when on the trail, especially something that is fairly technical, rocky, and steep. You are not going to idle up any obstacles with a manual if you stay in 4 high. If you need wheel speed with a manual trans just shift to a higher gear in the transmission. Even in a Rubicon with the 4:1 low range t-case if you shift into 4th gear in the trans that allows more wheel speed than 1st gear high range. Yes, there are some situations where wheel speed makes a difference, but I've seen very, very few times where somebody actually shifted from low back to high.
 

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word302

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Huh? Maybe we are talking about different things? I'm talking about shifting the transfer case into 4 low when on the trail, especially something that is fairly technical, rocky, and steep. You are not going to idle up any obstacles with a manual if you stay in 4 high. If you need wheel speed with a manual trans just shift to a higher gear in the transmission. Even in a Rubicon with the 4:1 low range t-case if you shift into 4th gear in the trans that allows more wheel speed than 1st gear high range. Yes, there are some situations where wheel speed makes a difference, but I've seen very, very few times where somebody actually shifted from low back to high.
Off-road means different things to different people.. 4 low isn’t typically used in sand or mud.
 

entropy

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Well said and straight on.



^That is me 100%. At this point, and I’m sure you’re the same way, I’ve put too much into my non-rubicon to go back. It’s also pride in building. Cheers!
Lol same here.

I am looking to re-gear and install a rear locker soon and that'll put me into Rubicon level sans front dana44 and 4:1 t-case. But it has been fun modifying the sport to my needs. Since I am about to drop 3k on this Jeep for the re-gear and rear locker I looked into buying a similarly optioned 2-door Rubicon; similar to my 2019 sport S.

The rubicon comes at 53k MSRP before taxes. I got a really good deal on my 2019 it was 31.5k before taxes. I could probably get some sort of deal on the Rubi, but it'll never be even close to what I paid. So now really I have 2 options.

1) Throw the 3k and have a cheap quasi rubi.
2) Get better than rubi axles already locked and re-geared and throw a nice RK suspension with 35s.

I am starting to lean towards option 2. it'll get me better than a rubi for a better price. But that's just cause I got a good deal on my sport. The caveat is once I sell the Jeep I am getting almost 0 return on upgrades. Unless I went through the trouble of swapping back to sport axles and selling the axles separately.
 

6.2Blazer

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Off-road means different things to different people.. 4 low isn’t typically used in sand or mud.
While I agree on it meaning different things to different people, I definitely wouldn't say it's "not typical" to use 4 low in the sand or mud. I've been wheelin' for over 30 years in the Midwest where a lot of of off-road is mud and snow. Yes, there are a few times where 4 high might work better or it simply doesn't matter but that is usually very light mud, snow, or sand. From my experience if you get into any moderate to heavy/deep mud, or even soft sand, most vehicles don't have enough engine power to really spin the tires in high range and will start bogging down. If anything they have poor throttle response in high range and can get the tires spinning faster in low range.
Our off-road club hosts "novice rides" several times a year and there are always people that start out in high range and struggle until we get them to shift to low. I've seen people flat out refuse to shift to low range stating they wouldn't have enough wheel speed to get through a mud hole, then watch them struggle through the mud with the engine bogged down and barely being able to spin the tires.
 

word302

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While I agree on it meaning different things to different people, I definitely wouldn't say it's "not typical" to use 4 low in the sand or mud. I've been wheelin' for over 30 years in the Midwest where a lot of of off-road is mud and snow. Yes, there are a few times where 4 high might work better or it simply doesn't matter but that is usually very light mud, snow, or sand. From my experience if you get into any moderate to heavy/deep mud, or even soft sand, most vehicles don't have enough engine power to really spin the tires in high range and will start bogging down. If anything they have poor throttle response in high range and can get the tires spinning faster in low range.
Our off-road club hosts "novice rides" several times a year and there are always people that start out in high range and struggle until we get them to shift to low. I've seen people flat out refuse to shift to low range stating they wouldn't have enough wheel speed to get through a mud hole, then watch them struggle through the mud with the engine bogged down and barely being able to spin the tires.
Look man, I’m always in low because mud and sand dunes are of no interest to me (unless I’m in a sand rail), I’m just saying different strokes for different folks. My main point was that your clutch doesn’t care if you’re in high or low.
 

6.2Blazer

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Look man, I’m always in low because mud and sand dunes are of no interest to me (unless I’m in a sand rail), I’m just saying different strokes for different folks. My main point was that your clutch doesn’t care if you’re in high or low.
I'm not arguing with you about using high or low range in certain situations, but I will argue with the comment about the clutch not caring if you are in high or low range. If you try to do anything halfway serious off road in high range you are either going to stall out the engine or going to slip the clutch to keep from stalling the engine, which will quickly burn up and wear out the clutch. So technically the clutch operates the same whether you are in high or low range, but it will get abused a lot more trying to off-road in high range in most situations.
 

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crackrk

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The caveat is once I sell the Jeep I am getting almost 0 return on upgrades.
If you’re going to do any kind of major upgrade (t-case, gears, axles) you really can’t think about return value. You have to consider “now” value. I’ve accepted that there’s no way in hell my Jeep is returning back to stock, or at least not on my dime. I’ve been selling off the stock stuff at this point.

As for your options I wasn’t exactly following with your current setup. That said with the price of regearing these days if you can find a set of front and rear rubicon axles I’d just go that way. You’ll save some money and it’s something you can swap yourself with the right tools. You’ll also have f/r d44 & lockers. Sure it only has 4.11 gears, but you’d be able to run 35’s with minimal noticeable impact on driving. Then later down the road should you decide to go to 37’s you can regear it properly for those tires (I’d go 4.88 or 5.13 depending on which transmission you have).

Like I’ve stated before, for me personally 4.56 + rubi transfer case + 35’s is pretty dang perfect. My jeep drives better then stock at this point with all of the stock like acceleration. If I’m not paying attention I can easily light up those 35’s. Maybe someday I’ll move to 37’s but I’m in no real rush right now.
 

c20040215

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Finally got an opportunity to do some hardcore wheeling after the transfer case swap at Hollerwood Park, KY. I know it is nothing special for Rubicon folks but I had been wheeling this JL sport for the last 4 years with different gear and tire size combo, and this is a game changer for me.

I have gotten a lot better with 2.72 T-case and I could manage most rock crawling without stalling but switching to 4:1 is like cheating.
Best way to describe it is when you are used to running 5k, 1 mile above sea level. And you are now running the same distance at sea level. Everything is so much easier.

This is one of the obstacles at Big Widow Maker Trail.
 

Rodeoflyer

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Congrats!!! Yes. the 4:1 is awesome. Now throw some 5.13 gears and just baby crawl up stuff.. it's nice.

I'll wheel with a lot of JK guys on 35/37's and the 4:1 TC with stock gears. They will shift and try to bump up and across obstacles. I just use the 95:1 crawl and wave out the window lol. It IS like cheating.

Mine crawls at about 1/3 the speed of yours in 1st and 4lo... just imagine. It's like a drug lol

If could go to 6.13 gears I would do it tomorrow.
 
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There are a few forum members who have done the transfer case swap. It is a pretty straightforward job but I thought I would share my experience and things to expect if you want to do it yourself.

Source: I assume most people who would consider the swap are 6MT non-Rubicon owners. The part number is 68321888 AB or AC. I got mine from Baseline 4x4 in Indiana for $1350. Another resource you can try is Tri State Auto Parts Inc. Both companies would ship it to you on your dime. The transfer case aren’t easy to come by but once Atlas starts shipping their transfer case, I suspect there will be more and more Rubicon takeoffs on the market.
Jeep Wrangler JL Swapping Rubicon T-case vs. re-gearing Sport axles received_1448143885687759


Tools: You don’t need any specialty tools but an assortment of extensions, swivels, wobbles, low profile sockets (13mm), and ratcheting wrenches. I use power tools here and there. Just be mindful the transfer case and the transmission case are aluminum and the torque spec isn’t much. A transmission jack would help, but normal jack would do the trick.
Jeep Wrangler JL Swapping Rubicon T-case vs. re-gearing Sport axles received_1448143885687759



Process:

  • Remove everything in the way including front & rear drive shafts to the transfer case and all the skid plates. Don’t forget to drain the Transfer case fluid.
  • Remove crossmember and everything bolt onto it including the fuel line cover on the passenger side and exhaust hanger bracket on the passenger side. Remove the 3 nuts that hold the transfer case mount on the crossmember side. Make sure to support the transmission before you start to loosen the crossmember bolts. 18mm bolts. 2 on the driver side and 3 on passenger side. Once the crossmember is removed, remove the 4 transfer case mount bolts on the transfer case side.
  • Before you separate the transfer case and transmission, there are a few Christmas tree clips holding the wire harness on the passenger side that need to be removed. Disconnect the shift linkage. On top of the transfer case, there is bracket that holds 3 shift cables. You can pop the cables out of the bracket, which was what I did, or you can remove the bracket completely. You will need to transfer it to the new transfer case anyways. There are 7 bolts (13mm) that hold the transfer case to the transmission. Support the transfer case before you start removing those bolts. With the help of my buddy and an assortment of extension, it was not hard to remove the bolts. Once those are removed, you can start wiggle it and slide it out towards the back of the Jeep. It is about 100lb so be careful. It’s definitely a two-person job. The wire harness has enough slack so you can lower the transfer case to give you more room to unplug the connector on top.
Jeep Wrangler JL Swapping Rubicon T-case vs. re-gearing Sport axles received_1448143885687759


Jeep Wrangler JL Swapping Rubicon T-case vs. re-gearing Sport axles received_1448143885687759

  • Transfer the shift linkage, breather tube, and shift cable bracket from the old transfer case to the new one.
Jeep Wrangler JL Swapping Rubicon T-case vs. re-gearing Sport axles received_1448143885687759

  • Reinstallation. Everything I have mentioned in reverse order. Now, it is a direct fit, but Rubicon transfer case is noticeably heavier, and the case on the input end shaped slightly different. The top 3 bolts are very hard to get to. See the picture where I circled green are easy and I was able to use a torque wrench to torque to spec. The yellow ones are tricky and could not be reached with a torque wrench, but I was able to get them tight enough. The red, well, good luck. lol
Jeep Wrangler JL Swapping Rubicon T-case vs. re-gearing Sport axles received_1448143885687759

Jeep Wrangler JL Swapping Rubicon T-case vs. re-gearing Sport axles received_1448143885687759

Jeep Wrangler JL Swapping Rubicon T-case vs. re-gearing Sport axles received_1448143885687759


As I stated, it is a straightforward swap and can be done in one day. There were a few moments where I questioned myself why didn’t I get a Rubicon to begin with. But I enjoy working on my Jeep and have learned a lot along the way. The journey is just as enjoyable as the destination.

At the end of the day, it is definitely worth the time and cost.

I went on a test drive. On 2H and 4H, everything feels the same which is a good sign and expected. With 5.13 first gear, 4 to 1 low range, and 4.88 final drive, it would idle up a lot of climbs. I have a trip planned late September. I will report back how it performs.
thank you for posting this! do you happen to know the torque specs for the bolts?
 

c20040215

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