Maybe you’ll finally be able to keep up with me now that you’ll have 2.72 available
Picking up where I left off
- Thread starter Chris
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No kidding. It's really hard to keep up with you when I'm in 4 LO currently.
I'm at roughly 97. You're going to be closer to 150
Too slow? What crawl ratio does your Atlas have?
MPH in gears.
Mine:
Your's:
I'm more shocked about the 6,000rpm 17mph in 4th. Looks like the days of flipping the OD switch are behind youNow that's a slow crawl
I'm more shocked about the 6,000rpm 17mph in 4th. Looks like the days of flipping the OD switch are behind you
Haha! I remember it well on my last Rubicon with the RubiCrawler. I'm not sure it would have been possible to go any slower.
I've been told my driving style can be aggressive at times. However I describe it as I think I know exactly how much gas to give it. So take this with a grain of salt because you may drive differently than you and because you may wheel different places than me.
I'm not going to claim to have figured ratios out by any means but here's what I've discovered so far with big tires and 5.38 gears.
Manually placing the 42RLE in 1st or 2nd gear helps with almost everything. But it also doesn't shift fast enough into 2nd for loose hill climbs. A 2nd gear start would be very helpful to avoid the slow shift.
The stock torque converter on the 42RLE might benefit from a higher stall speed when using 5.38 gears in the axles so the 4.0 engine can get into the power band when the wheels are bogged down (if you've ever been in deep wet snow and the wheels won't spin even with your foot on the floor you'll know what I mean.).
The Rubicrawler in low in front of a 4:1 in low is too low for anything I've come across.
4:1 is about perfect for rock crawling (although haven't tried Moab style crawling). But not enough wheel speed for anything else.
Dirt/mud/gravel/snow/sand is not great with any ratios because the engine doesn't have enough HP and if you gear too high you don't have enough torque. 2.72:1 can be okay for trails where it won't get bogged down.
This isn't an issue experienced really with the 4.0, but if you go too low on gearing (too high on torque) you get wheel spin on loose stuff but it doesn't catch and grab. Placing the trans into a higher gear can help with that.
With my LS3 making 430hp and 430tq (more just off idle than the 4.0 has at peak) and deep 1st gear on the 6L transmission, I made a gamble to go with a 3:1 transfercase. It's either going to be bad at everything or with the wide gearing span on the transmission it might be really good.
Getting back to the 4.0... If you're not planning on wheeling outside of the rocks. I'd stick with the simplicity of the 4:1. If you plan to go other places, having the 2.72:1 of the Rubicrawler is better than the 4:1.
I'm not going to claim to have figured ratios out by any means but here's what I've discovered so far with big tires and 5.38 gears.
Manually placing the 42RLE in 1st or 2nd gear helps with almost everything. But it also doesn't shift fast enough into 2nd for loose hill climbs. A 2nd gear start would be very helpful to avoid the slow shift.
The stock torque converter on the 42RLE might benefit from a higher stall speed when using 5.38 gears in the axles so the 4.0 engine can get into the power band when the wheels are bogged down (if you've ever been in deep wet snow and the wheels won't spin even with your foot on the floor you'll know what I mean.).
The Rubicrawler in low in front of a 4:1 in low is too low for anything I've come across.
4:1 is about perfect for rock crawling (although haven't tried Moab style crawling). But not enough wheel speed for anything else.
Dirt/mud/gravel/snow/sand is not great with any ratios because the engine doesn't have enough HP and if you gear too high you don't have enough torque. 2.72:1 can be okay for trails where it won't get bogged down.
This isn't an issue experienced really with the 4.0, but if you go too low on gearing (too high on torque) you get wheel spin on loose stuff but it doesn't catch and grab. Placing the trans into a higher gear can help with that.
With my LS3 making 430hp and 430tq (more just off idle than the 4.0 has at peak) and deep 1st gear on the 6L transmission, I made a gamble to go with a 3:1 transfercase. It's either going to be bad at everything or with the wide gearing span on the transmission it might be really good.
Getting back to the 4.0... If you're not planning on wheeling outside of the rocks. I'd stick with the simplicity of the 4:1. If you plan to go other places, having the 2.72:1 of the Rubicrawler is better than the 4:1.
Do you feel like the 10:88 on the RubiCrawler might be beneficial in situations where you are descending down an extremely steep hill in 4LO? I could see it being useful because then you're not having to rely on the brakes nearly as much. Obviously I have a 16" Vanco kit, so I've got good brakes, but you know what I mean.
So far the 4:1 ratio has been all I've needed in the rocks. Truth be told, I can't imagine where I'd ever need 10:88. However, @starkey480 seems to know of some places, and perhaps @mrblaine knows of some places as well.
I don't know much about crawl ratio's that low. The options it provide seem like it could be nice. I know there are always Toyota guys chugging along on the Rubicon with crazy low crawl ratios that seem to like it.
Wrong guy to ask. I have the 4.3 Atlas, 4.88 gears, 40" tires and I've never wished for or needed lower gearing.
Maybe on sticky rocks like in Moab. Anything that has dust/gravel or is loose, I don't think so. 4:1 and put the trans in 1st gear until you get to the bottom.
I'm second guessing my decision to buy a RubiCrawler now. I could probably just just put the money into an ARB or Eaton rear locker, Detroit full case in the front, and 5.38 gears.
In my mind I like the idea of being able to have all those extra ratios "just in case", but in reality I don't see myself really going wheeling much outside of Arizona, California, and possibly Utah very rarely.
Me wanting to build my LJ Rubicon with a 10 speed automatic with my doubler and NP241OR transfer case with a crawl ratio of 210.17:1
In a way that answers my question. If you don't see a need I don't think many would.
Having a doubler is freaking awesome, especially for being able to have a 2wd Lo, I already know I'm going to miss it on my TJ but I'll install it on my LJ Rubicon for sure.
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Resoundingly so.Might be cooler
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