Topic: can someone explain the dual t case to me???

[weirdtimes_7]

i do feel dumb for asking, but i really want to know how it works.... is it just the fact that you have two transfer cases running different gears to the front and rear??? so you can have the front at lower gears and the rear at higher... please, someone help me out...

military_stang

[Shamb]

The engine turns the tires. So in order

Engine transfers rotation to Transmission, Transmission transfers rotation to transfercase(S) then through the drivelines into the ring and pinion gears which turn the axles that turn the tires.

Hard to explain but think of it as a math equation.

If I have a 3.93 to 1 1st gear ratio in my transmission, then a 2.28 to 1 low range in my transfercase and a 5.29 to 1 ring and pinion gear set in your axles then the way you determine your crawl ratio is

Transmission 1st gear times transfercase times ring and pinion gear = crawl ratio
3.93x2.28x5.29 = 47 to 1 crawl ratio

Stock dual transfercases double that ratio because your adding another 2.28 to the equation so instead it would look like this with the same setup in the example

3.93x2.28x2.28x5.29 = 108 to 1 crawl ratio

So by adding that second transfercase (crawl box) your increasing the amount of torque that is concentrated to those wheels, thus giving you better traction.
More gears = slower speed

I'm not very good at explaining but that gives you the rough idea, i'm sure someone will post up specifics. 

[Tice]

i do feel dumb for asking, but i really want to know how it works.... is it just the fact that you have two transfer cases running different gears to the front and rear??? so you can have the front at lower gears and the rear at higher... please, someone help me out...

military_stang

Are you thinking two cases, one for front axle and one for rear? Dual cases is the low range box of one case bolted to the tranny, then an adapter, then a whole t-case bolted to that.  The front case is just hi- neutral-low, the rear case has every thing. For crawlin you'd put the front case in low and the rear case in 4-lo. The reason for duals or duals with 4.7's is for slowing down your rig to climb easier.   Shambs explanation is good.

[chaseheadrick]

it might make more sense also to think of them as reduction cases rather than transfer cases. shamb did have a good explanation in that you have:

engine>transmission>(reduction case)>reduction case w/transfer>front/rear drive shafts>axles

the transfer case is what actually disperses power between the front and rear axles. so what people really mean when they say they have two t cases, is they have two reduction cases. the rearmost reduction case also happens to be a transfer case.

maybe that helps, maybe i made it worse

[weirdtimes_7 [OP]]

acctually, ya'll did a dang good job of explaining it to me, thank you very much. I am starting to get a really good idea of em... Again, thank you...

military_stang

[dino1967]

was wondering the same thing thanks for the info guys