[s-cars] NAC - Why is manual and full-time 4wd or AWD mutually exclusive in SUVs

[Taka Mizutani]

The only 4WD vehicles available with the manual, off the top of my head:
Jeep Wrangler
Jeep Liberty
Nissan Xterra

The vehicles you mention below are not available with a manual in the US, at
least- Explorer,
Pathfinder, 4Runner.

Most of the 4WD trucks lack a real center diff, so if you engage 4WD, the
front and rear axles are locked at turning at the same rate (like a locked
center diff). This is not good on dry roads due to driveline binding when
you turn.

These days, SUVs are pretty luxurious and very far from their utilitarian
roots- automatic transmissions and AWD is the norm rather than the exception
now- you have no demand for a manual transmission in that market.

Not to say that you can't have a proper AWD SUV with a manual- the FJ80
Landcruisers had a manual with the turbodiesel outside of the US and they're
full-time AWD with lockable center and rear diffs, some even had lockable
front diffs.

BTW, be very careful with "AWD" trucks these days- a lot of them don't have
a real AWD system, but rather have triple open diffs and rely on the
traction control system to brake the slipping wheel to prevent traction
loss. This does not work in low friction situations like deep snow, slushy
conditions or ice. To prevent the accidental purchase of one of these "AWD"
trucks, I'd rather pick one of the "auto-engaging" 4WD systems- like the one
in the Chevy/GMC Tahoe/Yukon/Avalanche or Nissan Titan/Armada.

Taka


On 6/25/07, Edward <audi.ed at gmail.com> wrote:
>
> Hello all,
> Very unrelated to UrS, but I am trying to find a high-clearance vehicle to
> tackle water bars so I can stop abusing my poor 95 S6...
>
> Much research has landed me the conclusion that the few high-clearance
> vehicles available with a manual (xterra, for instance) are part-time 4wd
> only.  Vehicles that in the recent past offered full-time 4wd or AWD and a
> manual (pathfinder, 4runner, explorer) only offer part-time with the
> manual.  (I'm looking at SUVs of this nature as vehicles like all-road and
> outback, while higher clearance than a car, do not really offer enough
> approach angle to actually clear the average BC water bar...)
>
> Is there some challenging technical reason for this that audi & subaru
> have
> overcome to get AWD and manual in their cars that doesn't scale to a
> bigger
> vehicle?  Or is this just a function of market?  Am I only one who wants a
> manual and on-dry-road 4wd?  Is there some vehicle I'm missing?
>
> Found myself curious and unable to solve on google... figured someone here
> *must* know!
>
> Thanks (and sorry for the NAC question),
>
> Ed
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