Re[2]: 4x4 242HD conversion

From: fawcett@uism.bu.edu
Date: Fri Jul 09 1999 - 20:46:26 EDT


<<full time four wheel drive has about 400 different meanings and every
manufacturer uses it differently. some manufacturers uses it differently
depending on which of their products they are refering two.>>

Yep, no doubt about it... Manufacturer's feel the need to name their system
something different. Can be very confusing.

<<a lot of people including myself think of it as power going to the front
and rear drive shafts all the time with torque going to the axle with more
traction. like the subaru line about the wheel that grips.>>

I would consider power going to both axles all the time as AWD. If the system
provides power to the wheels that grip, then they've upped the anti with a more
sophisticated system like LSD's, computer controlled braking, or something else.
        
<<there are 4x on demand, which is most trucks have. there is slippage then
it engages like a part time unit with a 50/50 split.>>

50/50 front and rear axle, but what slippage are you talking about?
  
<<then there are the all-whell drive types. power is sent along both shafts
all the time. the case is a viscous coupling. and power is sent to the
shaft with more power. this unit type is found in subaru's and non-off road
4wd drive units (syclone). the only problem is most of these can not be
locked like part time 4x.
        now there are all types of transfer cases some like the above examples
some unlike, some are a combination.
        the 242 is somewhat different from the above it is more like a part time
unit that is set up to allow slippage when in the full time mode.>>

I'm still confused on your use of the word "slippage". I thought you were
referring to a LSD but that doesn't add up. A "viscous coupling" is just
another word for a clutch pack A.K.A. LSD, no? My understanding is that the
242 has something similar to an open differential in the T-Case. Therefore,
there would be no slippage, power would simply go the path of least
resistance to either axle.

<<my experience is this. the 242 is a great transfer case 2wd high, 4 high,
4 low, and the full time mode works well, but never anywhere as well as when
it is part time. It is most noticeable when you are giving lots of power in
very slick situations(ice, deep snow, mud). basicaly trying to spin yourself
out. but, in rain, light snow, dirt at safe speeds it works great.>>

Yep! That's what it was designed for... I would never recommend
full-time on the Kota for any serious off-road trails or if your stuck in
stuff --it doesn't work that way and was never designed to.

<<note
  -when in part time on slick surfaces if you lock one wheel all of the
others that are connected
     lock up as well (through drive train) I learned the hard way that abs
is very good.
  -the 231 part time unit is rugged, your not going break it very easily.
short straight drives on hard pavement and extended drives on packed
earth/gravel will not damage it.>>

Driveline lock-up sucks! I had it happen once in my old Jeep --not fun.

Straight and level with full lockers front and rear will never damage any
4wdr system... I've never met a road that stayed straight for long,
though. The problem is, and will always be, turning with a part-time
system. If anyone doubts me, slip your truck into part-time high and try
to make a VERY slow speed turn on some dry pavement (try this only once
and don't complete the turn!)... As soon as you start turning you'll
think your driving a pogo stick. That's your driveline binding up --very
bad!

Tom



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