Transfer Case: 2 Hi to 4 low.

[sdotcarter]

Hey guys,

A long time lurker here, and had to register because I cant quite wrap my head around something.

Im looking to reproduce my jeep wrangler minus the 5 speed transmission. I have the solid axles built, but im looking for a transfer case.

2 hi, a faster speed just by rear wheels along with a driving ring selector for a 4 low. ( 4wd crawling ratio )

My wrangler is equipped with a np231 t-case

http://www.thejeep.c...part4/H12-4.gif

Is something like this replicable with lego?

I try and build first in my head but this particular thought i cant figure out but maybe its simple.

Anyways, thanks for having me, and good building.

Edit:

Power through 1 xl or two l's if that matters

Edited June 4, 2014 by sdotcarter

[Rockbrick]

use something like this in the centre drive shaft but with one side 'locked' all the time (for the rear wheels) then you can use a selector to also engage the front axle or not

then using the larger ring or smaller ring you can achieve low or high ratio - but would require another selector I can't see how to do that with just one selector at the moment

Edited June 4, 2014 by Rockbrick

[aeh5040]

Here you go:

[Bzroom]

That's really awesome. I wish i had room for this in my 4x4 moc

[aeh5040]

That's really awesome. I wish i had room for this in my 4x4 moc

Well, of course it could be made more compact in various ways...

[Rockbrick]

Nice one!

Here you go:

[sdotcarter]

aeh5040,

That is pretty much a marvelous solution, but I spot 1:1 ratios for both 2hi and 4 low.

Since your more talented then me can a solution be made from this? Or would a two speed gear box be needed?

[Bzroom]

When you stall one side of the differential, through the planetary gears, the other side is driven with twice the speed.

[aeh5040]

aeh5040,

That is pretty much a marvelous solution, but I spot 1:1 ratios for both 2hi and 4 low.

Since your more talented then me can a solution be made from this? Or would a two speed gear box be needed?

Nope. "Hi" is a 2:1 ratio (geared up), "Lo" is 1:1, as Bzroom says. Just try it :)

Differentials can be tricky ...

[Hrafn]

I just realized one way to make aeh5040's design more compact while also adding the ability to lock the differential while in 4x4 mode. The differential case should be driven. When the driving ring is to the left, it's 2WD high mode; in the center, 4WD low with an open diff; and to the right, 4WD with a locked diff.

[Technic Builder]

The above example is very compact, but when in 2WD high mode wouldn't the front axle be locked? In other words, the front wheels still roll on the ground, they still turn the front diff which in turn turns that axle which would be not able to move due to the driving ring bing slid to the left.

[Hrafn]

The above example is very compact, but when in 2WD high mode wouldn't the front axle be locked? In other words, the front wheels still roll on the ground, they still turn the front diff which in turn turns that axle which would be not able to move due to the driving ring bing slid to the left.

Yeah, I realized that right after posting it. There are ways of dealing with that issue (ratchet clutch, second driving ring disengaging the front prop shaft, etc.) but then the design is no longer more compact than the original.

[sdotcarter]

Appreciating all the comments and help guys.

With summer here my fishing vessel gets top priority but I plan on building the frame + axles within the next week. Id like to do a "super car" but I doubt i have the skills to do it.

Thanks again guys.

[Thobricks]

Hello,

I would Need a Transfer case with three positions:2WD,4WD, 4WD Low. Better syncronized, linear should be no Problem.

any idea?

Thank you

Thanks

[Blakbird]

I would Need a Transfer case with three positions:2WD,4WD, 4WD Low. Better syncronized, linear should be no Problem.

any idea?

Sheepo's Land Rover has exactly that system. You might want to check that out as a starting point.