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Discussion Starter · #1 ·
I read about the aftermarket "Lefty" transfer case. Anyway I am not sure I understand it fully; what are the advantages? If it's "only" about the higher ratio, isn't it possible to modify the OEM one?
 

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I read about the aftermarket "Lefty" transfer case. Anyway I am not sure I understand it fully; what are the advantages? If it's "only" about the higher ratio, isn't it possible to modify the OEM one?

No, you cannot get different gears for the stock transfer case due to it size. It is also a chain driven vs. gear driven.

If you want a higher gearing in the transfer case your only option is aftermarket cases like the Inchworm and Atlas.

The advantages of a higher crawl ratio while offroad are much slower crawl speed, more control, more torque to the wheels, etc.

I will add this though, the only transfer cases i have heard of breaking out on the trails are aftermarket ones. I haven't heard very much about people breaking the stock transfer case.
 

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Discussion Starter · #3 ·
Oh and I also read in the meanwhile that on a Manual Transmission, one would lose the "permanent" 4WD mode...
 

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Oh and I also read in the meanwhile that on a Manual Transmission, one would lose the "permanent" 4WD mode...
The manuals have a full-time 4wd transfer case setup.
There is a center differential that splits torque between the front and rear wheels allowing slippage so that binding does not occur when turning. Then you have 4HI-lock, and 4-LO-lock.

The auto has a part time transfer case just like the aftermarket ones.

So yes, if going with an aftermarket case, you are going to loose full-time 4WD. Some like this some don't.
 

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Discussion Starter · #5 ·
Well the full-time 4WD is one of the reasons I bought it ;) so I guess I will have to keep the current crawl ratio. Thanks!
 

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nothing impeding you from leaving it @ 4HI while driving and not using 2HI on the aftermaket ones.
you have the extra flexibility of chosing 2 or 4wd.... stock M6 doesn't provide that flexibility.
 

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Discussion Starter · #7 ·
nothing impeding you from leaving it @ 4HI while driving and not using 2HI on the aftermaket ones.
you have the extra flexibility of chosing 2 or 4wd.... stock M6 doesn't provide that flexibility.
No, my understanding from this thread is that one can't use the "full-time" 4WD with the "lefty".
 

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As far as I know, when you get the lefty you sacrifice the full time $WD (i.e being able to have all wheel dry asphalt without any binding) but you gain the ability to choose any combination of 2wd or 4wd and hi or lo. It's a dual stick setup in addition to the shifter stick. The main advantages are in the ratios. I have followed an FJ with a lefty on a bunch of trails and I'm amazed how slow and steady it crawls while I am trying not to stall out in 1st and have to either power through lines faster tan I would like or stop re-assess and then go for it.

The other big draw is that the lefty gives you a lot more clearance. So if you go with the lefty, re-route the exhaust and replace the rear crossmember the FJ becomes completely flat underneath. Personally I am not ready to give up the onroad 4WD but having nothing protrude from the under body to catch on obstacles would be a big help on the trail. Do a forum search for tummy tuck and you should find some info.
 

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nothing impeding you from leaving it @ 4HI while driving and not using 2HI on the aftermaket ones.
you have the extra flexibility of chosing 2 or 4wd.... stock M6 doesn't provide that flexibility.
Just like with an AT you can't put it in 4hi while on dry pavement.
 

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No, my understanding from this thread is that one can't use the "full-time" 4WD with the "lefty".
The stock T-Case in the manual is a constant 4WD model. It allows for differential between front and rear output. When you lock it in 4L it locks out that diff function and only the axles provide diff functions.

The lefty is an older gear driven style transfer case that has been modified for a left hand drop that the FJC requires, thus "Lefty" This case lends itself to being able to use lower gears. Makes a big difference in how the FJC handles on the trail. There is thought that this case is not robust enough to handle the weight of the FJC.

With the Lefty you can run it in 4H on the street but not advised. You can lock in 4H on road when required like in snow.
 

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even if one was to drive on 4Hi w/ a lefty, there is still the front diff to allow differencial from left/right... same for the rear axle.
Under which circumstance does the front/rear differential come into the picture ?
The only thing I can think of is when someone is doing sharp turn like a U-turn where the rear-wheel radius will be a bit smaller than the front wheel radius.

So, are there any transfer cases like a lefty that allow a lock and a non-lock position for the center... the non-lock would probably act as a torsen w/ limited slippage ?

Am I day dreaming ?
 

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if not mistaken, the RAV4 has that on the transfer case, no? locks the transfer case to a 50-50 split while under normal conditions it allows some slippage.
I know we can't compare... but just saying.
 

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even if one was to drive on 4Hi w/ a lefty, there is still the front diff to allow differencial from left/right... same for the rear axle.
Under which circumstance does the front/rear differential come into the picture ?
The only thing I can think of is when someone is doing sharp turn like a U-turn where the rear-wheel radius will be a bit smaller than the front wheel radius.

So, are there any transfer cases like a lefty that allow a lock and a non-lock position for the center... the non-lock would probably act as a torsen w/ limited slippage ?

Am I day dreaming ?
Take your FJ, put it in 4Hi or 4Lo on dry concrete, turn the steering wheel all the way to one side, and try to drive forward, see what happens. It doesn't even have to be a sharp turn. :) Even barely turning the steering wheel is going to cause this problem on dry surfaces.

Just because you have open differentials in both front and rear does not matter when the front and rear axles are locked together. When turning, no wheel travels the same turning radius therefore all 4 wheels rotate at different speeds. In 4Hi/Lo the fr/rr are locked together so you are going to get binding.
 

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Ok just a bit confused here. I will be looking for an "upgrade" in the future for lower crawl ratio. Why are you all so much in need for Awd...on dry pavement? My FJ barely needs 4wd in the snow. Tire choice makes a huge difference,

I guess its good to have on that occasional wet patch but I’ve not "lost it" with my part-time.

My main reason for looking at lower ratios is that while A-Trac is useful, it’s not that desirable on rocks (not a mudder here). Also hoping the lower gears would play less havoc on the torque converter with less stabbing the throttle. Plus the higher breakover is a nice plus.

:cheers:
 

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Take your FJ, put it in 4Hi or 4Lo on dry concrete, turn the steering wheel all the way to one side, and try to drive forward, see what happens. It doesn't even have to be a sharp turn. :) Even barely turning the steering wheel is going to cause this problem on dry surfaces.

Just because you have open differentials in both front and rear does not matter when the front and rear axles are locked together. When turning, no wheel travels the same turning radius therefore all 4 wheels rotate at different speeds. In 4Hi/Lo the fr/rr are locked together so you are going to get binding.
This seems to be the case for Automatics... not Manual Transmissions.
 

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My main reason for looking at lower ratios is that while A-Trac is useful, it’s not that desirable on rocks (not a mudder here).

:cheers:
I thought the opposite of a-trac. It seems like I get better benefit from a-trac. while crawling rocks. I haven't seen the benefit from the mud at all.
Of course, living in AZ, my experience is limited to monsoon and trips to other locations.
 

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I thought the opposite of a-trac. It seems like I get better benefit from a-trac. while crawling rocks. I haven't seen the benefit from the mud at all.
Of course, living in AZ, my experience is limited to monsoon and trips to other locations.
While my experience is limited to WTF in the FJ, I have been with friends in SA trucks and can say the lower crawl seems to make it easier to maintain steady forward progression without the need to burn up the TC running the brakes with the gas. Even a 4:1 would be better- the FJ has great torque to make even 35's (with the right gearing) rock, but the higher stock ratio seems to require more gas and less finess.

I'm not saying the A-Trac doesnt have its merits- works very well at keeping people like me from blowing things up while turning on the rocks. It would keep that but would like a locker in the front and a little more grunt from the gears- thats all.


Besides- it keeps giving me reasons to add things to my Mod list...:lol:


:cheers:
 

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I have really been enjoying my Atlas. Not only is it great for control while going up rocks, but the benefit of going down steep hills without using breaks is priceless.

I have the 3.8 geared Atlas and 3.56 diffs. This equates to a 61 to 1 crawl ratio in low low. I know the Lefty runs lower and some say too low. The thing that made me go Atlas though was the fact that lots of people were blowing up their leftys on the FJC platform.
 
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