Alert!! Jeep Cherokee Transmission Safety Problem
Jim Nasset
The following information has been brought to light as to the full scope
of the Jeep Cherokee AW4 automatic transmissions 1-2 downshifting design
defect. It came to my attention by a driver who spun out of control in
Drive gear position while slowing down during slippery conditions. He
had
e-mailed me for information on the CompuShift Plus. I then searched a
few news forums looking for similar mishaps and found the following
instances which I have included below.
Until this time I was simply advising people of the hazards of
downshifting to second gear(the 1-2 position)with their Cherokee when on
slippery or icy conditions. I was not aware that the same unwanted
downshift could occur while the shift lever was in the normal Overdrive
or Drive positions.
I know that the last time I sent out information about the Jeep
Cherokees automatic transmission problem I was taken to task by some as
being an alarmist simply wanting to prey on peoples fears to sell a
product. I am sure I will hear from some of those same people again,
however if you read the owners problems below you will see that this is
not the case. Yes I have a product which solves the abrupt automatic
downshift to first gear problem, however although the Chrysler has been
aware of the problem since at least 1992 (this is when I notified the
Director of Safety, Darrel Dawkins) they continue to refuse to do
anything about it or even to
notify Cherokee owners of the hazard. I therefore will continue to
do so and take any heat that may come from it.
Best Regards,
Jim Nasset
Aftermarket Innovations
http://www.inventorworld.com/ami/jeep.htm
Subject:
Compushift...
Date:
Wed, 05 May 1999 12:22:09 -0400
From:
Wunder Phish <jdg...@is5.nyu.edu>
To:
am...@sprintmail.com
I have a '90 XJ, and I was wondering: this sudden downshift, does it
happen
ONLY when the auto tranny is in 1-2? Honestly, I've gone flying off the
road backwards TWICE while doing about 30mph, both on ice with little
snow
buildup to slow me down. Both times, however, I was in full time 4WD,
with
the tranny in D, and I don't think I did anything to cause it - I didn't
touch the brake, and the car just jerked slightly and started to do a
180.
And if this problem DOES happen in D, would I have to shift into 1-2 so
the
compushift would eliminate it?
Anyway, I'd really like to know what's going wrong, since one of those
times, my XJ actually ROLLED, which could have been really bad for my
health.
Thanks for your time,
James Greenan
Subject:
Re: Compushift...
Date:
Wed, 05 May 1999 12:06:55 -0700
From:
Jim Nasset <am...@pop.a001.sprintmail.com>
Organization:
Aftermarket Innovations
To:
Wunder Phish <jdg...@is5.nyu.edu>
References:
1
Thanks for the inquiry James,
In answer to your question, your transmission should never downshift
automatically to low gear at 30 MPH while in the Drive, or 3rd gear
detent when you are decelerating. If it does you may have a problem
with the Transmission Control Unit, or you could have a mis-adjusted or
loose 1-2 detent activation switch on your transmission. If this were
the case, the TCU would think that you were in the 1-2 position (when it
was given a false signal from the 1-2 position switch) and when you
reached 28-20 MPH it would go to low gear automatically. (Not good as
you have noted!!) However, either way if you were to install a
CompuShift Plus on your Cherokee and keep the Power/Comfort switch in
the comfort position, the transmission would not downshift into low gear
automatically whether the selector was in Drive, 3rd or the 1-2
position, as the CompuShift would prevent it from doing that. You would
have to select the Activation switch in order to get first gear on
downshift.
Hope this helps. If you have any more questions, or would like to order
one give me a call. My number is 800 528 6900.
Thanks again,
Jim Nasset
Aftermarket Innovations
P.S.
I would also be interested in hearing more about your loss of control as
I have been trying to get Chrysler to fix this problem for years. Yours
is the first time however that I have heard of it happening in Drive.
Subject:
Re: Compushift...
Date:
Wed, 05 May 1999 17:59:24 -0400
From:
Wunder Phish <jdg...@is5.nyu.edu>
To:
am...@sprintmail.com
References:
1
Well, I'm fairly certain that my transmission doesn't think I'm in 1-2
when
I'm in drive, otherwise I'd have a good deal of trouble hitting highway
speed, which I don't.
As for exactly what happened to me, the first time I was driving on a
tiny
little state road in Illinois, which was straight and flat, even for
Illinois. It was basically during an ice storm, where it wasn't snow,
but
it wasn't big enough to be hail, but it was definitely frozen. I was
doing
around 30-35 mph. A large car was coming the other way, and to be safer
when he went by, I let off the gas when I saw him, coming over the
rise. I
got down to 20-25, as he passed me going quite fast the other way, and
when
he passed, I felt the rear end kick out towards him, in his wake, as if
pulled by the passing of his car. To compensate, since I was in 4WD, I
gave the car a good deal of gas, with the wheels turned in the direction
the rear end was trying to go. This, however, brought me up to 30-35
mph
and put me right in the middle of the road, with a STOP sign a good ways
ahead, and it was only a three way intersection, with my way being the
way
that didn't keep going. I was then concerned about my speed, and let
off
the gas entirely. I drove straight, decelerating with no gas/no brakes.
And after maybe 100 yards from when it first started to spin, it started
AGAIN, same slide, different direction, this time to the right. So the
rear end was sliding out to the right, I compensated the same way,
overcompensating, I'm sure, so I got going straight just to see the rear
keep sliding around LEFT. It kept going until I was completely
backwards,
and which point I just departed the road in classic style, ass first,
into
a drainage ditch for some farmers corn field, which is maybe 3-5 feet
deep.
(Since the rear end went left, I went off the left side of the road, as
well.) So the Jeep landed with enough momentum that it ended up flat on
the passenger side. I should point out that the road was so slippery
that
when I climbed out my door, and slogged through the ditch, the first
step I
took on the road surface resulted in me falling backwards into the
ditch.
The second time was much simpler than the first. Straight downhill. No
other car. Speed 30 mph. The downhill was letting my speed drop, just
barely, so I was coasting along again, no gas, no brakes. Completely
out
of nowhere, the rear end went right again, and since it happened so
SUDDENLY, and I was all the way on the right side of the road, I didn't
have time to do than say "OH (insert favorite expletive here), NOT
AGAIN!"
At which point I buried the rear of the Cherokee into a snowbank. It's
especially noteworthy that I did NOTHING to change the direction/speed
of
the car. This was halfway through a 30" snowstorm, somewhere in upstate
NY, near Canada.
Okay, story time's over. Good luck figuring it out, I know I can't,
James
Subject:
Re: Compushift...
Date:
Wed, 05 May 1999 16:28:47 -0700
From:
Jim Nasset <am...@pop.a001.sprintmail.com>
Organization:
Aftermarket Innovations
To:
Wunder Phish <jdg...@is5.nyu.edu>
References:
1 , 2
Well James,
I still can't rule out the TCU having a glitch in it, and although your
1-2 switch may not be totally out of adjustment, if it was loose at all
it might give you an intermittent problem during vehicle operation,
especially when changing momentum by letting off on the gas. Stepping on
the gas again may have caused the switch to break contact. Sorry but
that is all I can think of at the moment. Have you ever had any problem
with it not starting in Park or Neutral, and had to jiggle the shift
lever to get it to crank? If so, the switch may not quite be lined up
right, or loose. If not the 1-2 part of the switch could be still be
going bad and shorting out occasonially or getting corroded. This or
the TCU is the only thing I know of that might cause it downshift to
first when in Drive or
Third gear position at that speed. It must be going to first, as a
downshift to Second at that speed should not cause the vehicle to go out
of control.
Who knows for sure, but the 1-2 operation as it comes from the factory
is definetly an accident waiting to happen.
Hope this helps, and good luck in finding the problem. I am sure it has
to be an electronic control problem though.
Jim
Subject:
More info on Cherokee Accident
Date:
Sat, 15 May 1999 08:57:01 -0700
From:
Jim Nasset <am...@pop.a001.sprintmail.com>
Organization:
Aftermarket Innovations
To:
jdg...@is5.nyu.edu
James,
I ran across these posts in another news forum while trying to come up
with an answer to your problem. One of the problems was definetely a
1-2 switch problem and I suspect the other one was too, although it
could also have been a TCU problem.
The one guy says that at highway speeds it shifted out of overdrive to
drive at will, sometimes at 70 MPH. It actually shifted from overdrive
to second. The proof of this is the fact that his tach registered 4000
rpm when it downshifted. If it had shifted to 3rd the rpm would only be
around 2600 depending on the rear end gearing. The 1-2 switch or
possibly the TCU could be the only thing that would cause this. The one
guy mentioned the TPS however it would only affect upshift and downshift
timing in correlation with the vehicle speed sensor, and gearshift
position selection, it could not CAUSE a downshift to second at this
rate of speed. In order for this to happen the TCU would have to think
it was in the 1-2 position, the TPS could not give it such a signal.
Because of these other posts' it is becoming obvious that this is not
just an isolated incidence. Although the CompuShift Plus would not
prevent the downshift to second gear with a malfunction of the 1-2
switch or the TCU, it would however indicate what had happend by turning
on the LED on the unit to let you know that it had shifted into second,
and it would then prevent the automatic downshift to first gear that
would subsequently occur at 28-30 MPH with this malfunction.
Intermittent problems, especially electrical or electronic ones can be
very hard to track down.
Hope this helps and good luck,
Jim
Posted by Bob on January 31, 1999 at 05:55:59:
My transmission will downshift from overdrive to drive - at will
sometimes. Further, sometimes you can hear the engine as
well as see the tachometer increase - up to 4,000 rpm) and the Jeep
still crusing at about 70 mph. When this occurs, I
pull off the side of the road and shut the ignition off, wait a minute
and start up again - with no problems! Here is my
situation; all this occurred at 30,000 miles - still under warranty. A
Transmission Control Module (TCM) was replaced.
However, now at 60,000 mile - out of warranty - the same problem is back
again. What are the odds of having two (2)
TCM's go bad? Jeep PR folks - check this out - acknowledge the fact the
dealer "perhaps didn't fix this problem entirely"
the first time. AND, Jeep is not in a position to now "subsidize" the
dealership! HELLO - what about the customer here?
So I am now faced with letting the dealer try (this would be their 5th
attempt - 6th overall) at fixing this problem. Now
(again, after warranty) the dealer feels it is a mechanical issue and
will be expesive to fix. Does anybody have any
experience with this problem I've outlined? Any help or suggestions
would be much appreciated. Any 'backyard'
mechanics have any suggestions for me to track down before I am faced
with no other alternative but to go back to the
dealership? Thanks in advance for any help!
Follow Ups:
Re: 1996 Cherokee with AW4 Automatic SpudGasket 14:35:05 2/02/99
(0)
Re: 1996 Cherokee with AW4 Automatic Chet - Grand Cherokee
Connection 23:01:42 1/31/99 (1)
Re: 1996 Cherokee with AW4 Automatic Doccers 07:40:52 2/04/99
(0)
Posted by SpudGasket on February 02, 1999 at 14:35:05:
In Reply to: 1996 Cherokee with AW4 Automatic posted by Bob on January
31, 1999 at 05:55:59:
I have an 88 LTD with a AW4 tranny.
I have had that same problem with the high rev's at crusing speeds till
one day i couldn't get out of the drive way with out
shifting to 1st gear then shifting to 2nd to get up to speed. I took it
to my local AAMCO dealer.
It ended up costing me 2 grand to have them rebuild the transmission.
After about 3 months later it happened again i
couldn't move till i manual shifted into first gearand so forth. So off
to AAMCO. After about a two days of them looking at it
they find it is the Neutral Safty Swith. DOH! What was the 2 grand for i
asked!
of course they gave me the run around with this and that. So it is now
costing me 275 bucks replace the switch. I'm writing
this as they fix it now so i will let you know what happend after i get
it back. I dun no may be it was the Neutral Safty Switch
all along?
Anyway ill have to see. Just thought i'd let you know maybe it will
help.
GOOD LUCK !
Follow Ups:
Posted by Chet - Grand Cherokee Connection on January 31, 1999 at
23:01:42:
In Reply to: 1996 Cherokee with AW4 Automatic posted by Bob on January
31, 1999 at 05:55:59:
Sounds to me like you may want to take a close look at the TPS (throttle
position sensor) for maybe problems there. This
sensor feeds the tranny (and engine computer) information on the exact
postition of the throttle - bad info - weird thing
happen!
Had a friend that had a tranny replaced - turned out that the only
problem was with the TPS - the AW4 trannies are
bulletproof so look into the electronics first.
Sincerely,
Chet
Jerry Bransford
previous posts. For some applications, I agree TOTALLY that the product
you are pushing is an excellent product. But HOW you choose to try and
boost sales of the kit is what I have a BIG problem with... playing on
the fear of a few people who are easy to sway. I'm around Jeeps all the
time and follow Jeep issues but I've yet to EVER hear of anyone's
transmission abruptly downshifting to first while in drive and creating
a problem. In my personal opinion, your current method of marketing is
simply misleading. Ethics?
Jerry
--
Jerry Bransford
PP-ASEL KC6TAY C.A.P.
The Zen Hotdog... make me one with everything!
Jeff Schwartz
preying on the fears of Cherokee owners. Where I come from we call 'em
leaches. With all the Cherokees in my neighborhood (on my block alone you
can usually find 3 or 4 of them parked) according to this character they
should be skidding all over the place. 100% unadulterated pure crapola!
--
Jeff Schwartz
I may not be as good as I once was but I am as good once as I ever was!
'97 Grand Cherokee Ltd.
/ \
#[||||||]#
* *
Remove nospam to reply
Jerry Bransford <jer...@home.com> wrote in message
news:373E41CF...@home.com...
Mark Tener
>
> This is, IMHO, just another SPAM posting, very similar to previous your
> previous posts. For some applications, I agree TOTALLY that the product
> you are pushing is an excellent product. But HOW you choose to try and
> boost sales of the kit is what I have a BIG problem with... playing on
> the fear of a few people who are easy to sway. I'm around Jeeps all the
> time and follow Jeep issues but I've yet to EVER hear of anyone's
> transmission abruptly downshifting to first while in drive and creating
> a problem. In my personal opinion, your current method of marketing is
> simply misleading. Ethics?
I know you're not going to read this Jerry but to everyone else...I only
wish that Jim Nasset of Aftermarket Innovations would fix his excellent
product so that it works flawlessly in 97 and newer XJ's without turning
on the Check Engine light.
I don't really care how he markets it...it's the same as any business
trying to sell its product...believe it or don't believe it...caveat
emptor and all that.
-MarkT
97 XJ 30x9.5 BFG AT's, JKS discon's, K&N air filter, Tomken skids, Bosch
H4's, front Truetrac