Help with Rubi Crawler

MericaMade

Active Member
Need some advise for good friend. My buddy has a 2010 JK with the 3.8 and RIPP Supercharger, DTD, and Rubi Crawler. Last week in Sand Hollow the Rubicrawler output shaft decided to shear in half on a pretty chill hill climb.

Then issue he is having is the RIPP is bringing on the power pretty violently in 4 low. Within 3 to 4 hundred rpms it spikes the power band really good on the dyno. He's thinking of swapping to a sport Tcase for a higher ratio and wants to know if the sport Tcase is weaker in strength versus the rubicon Tcase?
 

fiend

Caught the Bug
I don’t think the sport TC is any weaker, but if he goes that route he will loose the main benefit of a Rubicrawler: having both 4:1 and a 2.7:1 ratios to work with (in addition to the rarely used 10.8:1). Instead he’d have a 2.7:1 and a 7.3:1. The latter is probably impractical for most situations, making the rubicrawler pointless.
 

MericaMade

Active Member
I don’t think the sport TC is any weaker, but if he goes that route he will loose the main benefit of a Rubicrawler: having both 4:1 and a 2.7:1 ratios to work with (in addition to the rarely used 10.8:1). Instead he’d have a 2.7:1 and a 7.3:1. The latter is probably impractical for most situations, making the rubicrawler pointless.
I believe that is the point to higher the gear ration to lesson the load on the Rubicrawler due to the supercharger. IF he were to go with the sport tcase would it be a simple bolt in or is there modifications needed?

Also, would a Atlas be a better option?
 

fiend

Caught the Bug
I believe that is the point to higher the gear ration to lesson the load on the Rubicrawler due to the supercharger. IF he were to go with the sport tcase would it be a simple bolt in or is there modifications needed?

Also, would a Atlas be a better option?
The Rubicrawler is between the AT and the TC. So I would think that changing the TC isn’t going to help the issue.

As for whether it’s a simple bolt in swap, I don’t know. Your friend should call Advanced Adapters with that question.
 
Sounds like its having a tune problem with the RIPP if its spiking like that, perhaps sensor issues, or even misfires or basic issues with the 3.8, the power should be pretty linear.
 

jdofmemi

Active Member
Sounds like its having a tune problem with the RIPP if its spiking like that, perhaps sensor issues, or even misfires or basic issues with the 3.8, the power should be pretty linear.
☝️This☝️

I remember the video lats year, where it was idle, or wide open, with little to no modulation in between.
Work on solving that, but he likely needs to go to an Atlas to handle the power anyway.
I don’t think the sport TC is any weaker, but if he goes that route he will loose the main benefit of a Rubicrawler: having both 4:1 and a 2.7:1 ratios to work with (in addition to the rarely used 10.8:1). Instead he’d have a 2.7:1 and a 7.3:1. The latter is probably impractical for most situations, making the rubicrawler pointless.
For what it's worth, that is how Vengeance is, and the 7.3 is way more useable than the 10.8 would be.

It works great on technical situations.
 

fiend

Caught the Bug
For what it's worth, that is how Vengeance is, and the 7.3 is way more useable than the 10.8 would be.

It works great on technical situations.
Interesting. I guess I could see that. I use the 10.8:1 occasionally, but it’s so low I just idle because I’m afraid of breaking something. But for certain situations it’s great. Gatekeeper to Hammerdown, for example.
 

MericaMade

Active Member
☝️This☝️

I remember the video lats year, where it was idle, or wide open, with little to no modulation in between.
Work on solving that, but he likely needs to go to an Atlas to handle the power anyway.

For what it's worth, that is how Vengeance is, and the 7.3 is way more useable than the 10.8 would be.

It works great on technical situations.
I did not realize that was Sahara Jerry. This is what he is thinking so I will let him know.
 
If you need a reason to get an atlas then yeah definitely, totally necessary upgrade to handle things, yup yup yup. Just tell the wife it’s needed.

Buuut are we pretending the reason he needs one is from the crazy amount of power a 3.8 with a screw slapped on makes?.... cuz... uhhh.... it isn’t ‘that’ much more power that it’ll break driveline from all its upgraded Tim Allen ‘more power!’ ::grunts::
 

MericaMade

Active Member
Does anyone know if a 2007-2018 Jk sport transfer case are all compatable with eachother and are pulg in play or are the 07-11 different then the 12-18 year?
 

fiend

Caught the Bug
Does anyone know if a 2007-2018 Jk sport transfer case are all compatable with eachother and are pulg in play or are the 07-11 different then the 12-18 year?
I read something about the AT and MT versions being different, but I don’t know the details. Maybe different input shaft?
 

fiend

Caught the Bug
Here is some verbiage from Advanced Adapters’ website. It pertains to the rubicon transfer case, but the change in input shaft from 2012 onward was due to the different transmission, so I would expect the sport TC would have the same issue.

“Prior to 2012, all Roctracs received a short 23 spline input shaft and were mated to either the 42RLE, NV3550 or the NSG370 transmissions. In 2012 Jeep retired the 42RLE and replaced it with the A580 five-speed automatic. The Roctrac used behind the A580 utilized a special 26 spline male shaft for the input.”

 

MericaMade

Active Member
Here is some verbiage from Advanced Adapters’ website. It pertains to the rubicon transfer case, but the change in input shaft from 2012 onward was due to the different transmission, so I would expect the sport TC would have the same issue.

“Prior to 2012, all Roctracs received a short 23 spline input shaft and were mated to either the 42RLE, NV3550 or the NSG370 transmissions. In 2012 Jeep retired the 42RLE and replaced it with the A580 five-speed automatic. The Roctrac used behind the A580 utilized a special 26 spline male shaft for the input.”


Good info and thanks I will read it now.
 
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