Hi, I`ve been having a problem with my 4wheel drive and, before I start
parts changing, I figured I`d ask. What`s happening is that my Jimmy is
dropping out of 4 wheel into 2 wheel. It`s intermittent, happens more often
when its colder outside, dash "service 4 wheel" comes on, and I lose 4
wheel. Happens in both Auto and 4High. Can be reset sometimes by restarting
the vehicle, other times not. A borrowed scan tool shows no hard codes but I
havent been in a situation to hook it up when its happening.
I`ve heard that the dash switch is problematic in this model with the Auto 4
wheel but was under the impression it was a complete failure problem not an
intermittent one. Ive done a good visual on the undercarriage,wiring to the
T/case looks good.
Any thoughts on how to proceed from here?
Thanks
Jeff
Any thoughts

JKBK wrote:
of common for the switch to get flakey.

It could also be a problem with the front clutch pack itself. When was
the last service of the front axle?


--
Steve W.
Near Cooperstown, New York

Life is not like a box of chocolates
it's more like a jar of jalapenos-
what you do today could burn your ass tomorrow!

"Steve W." <csr684NOT (AT) yahoo (DOT) com> wrote

Aside from an oil level check (and the usual tierods, ball joints, etc.) in
the summer, I havent done anything with the front axle since I got the
vehicle in 2005. Would a front axle slipping cause a system fault? I would
think it would no actual 4 wheel. With the intermittent nature I dismissed a
mechanical problem with the T/Case or front end and leaned toward electrical
especially with some basic research indicating the problemic behavior of the
system.

JKBK wrote:
The way the auto 4x4 works there are a lot of items that can cause
system faults. The switch and TCCM along with the front clutch packs are
the common fault areas.
If the scan tool you borrowed may not be able to read the codes from the
TCCM. If the light came one there will be a code stored. You might want
to take it to a dealer/independent who has a factory style scan tool.
That way to can find out what it is doing.

--
Steve W.
Near Cooperstown, New York

"Steve W." <csr684NOT (AT) yahoo (DOT) com> wrote

Thanks Steve
It was a snapon series scan tool from the local high school mechanics
program which is why I`m perplexed as to no code. It is working properly as
it is showing a code for my fuel sending unit but nothing else. I understand
the TCCM is by the front axle T/C output but I`m hearing clicking in the
glovebox area when I`m having the trouble. Is there a module under the dask
that controls the system/TCCM?
Jeff

JKBK wrote:
The TCCM on that rig is behind the kick panel on the passengers side. It
may be what you hear clicking. It is possible the contacts have gotten
corroded casing a problem. The T/C Encoder motor is on the case.
http://www.kylestubbins.com/node/11 has a nice write up about the connector.

--
Steve W.
Near Cooperstown, New York

Life is not like a box of chocolates
it's more like a jar of jalapenos-
what you do today could burn your ass tomorrow!

"Steve W." <csr684NOT (AT) yahoo (DOT) com> wrote


Thanks. In light of the clicking and the TCCM location, that seems like the
best place to start.
Merry Christmas
Jeff