My 1990 Jeep Cherokee won't shift
 

My Jeep cherokee 4x4 has an automatic transmission with overdrive.The
problem I am having is with the transmission not wanting to shift. In
order for me to get it to shift i litterally have to wind the engine out.
It shifts from low to second gear at 35 mph and then will not shift into
the next gear until you reach 65 mph. It seems to be intermittant as
yesterday when I first drove it it worked perfectly but later the same day
it started acting up again and still is not right. Can anyone give me some
advise. I am thinking that it could be the electronic shifting control
module, but I know nothing about this, Thanks

Have you ever done any maintenance on the tranny, flush (not drain oil) new
filter every 30K (cost $150.00 each flush), if not it is time for a new
tranny.

--
Coasty
SEMPAR PARATUS
(ALWAYS READY)

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"davees90JEEP" > wrote in message
lkaboutautos.com...
> My Jeep cherokee 4x4 has an automatic transmission with overdrive.The
> problem I am having is with the transmission not wanting to shift. In
> order for me to get it to shift i litterally have to wind the engine out.
> It shifts from low to second gear at 35 mph and then will not shift into
> the next gear until you reach 65 mph. It seems to be intermittant as
> yesterday when I first drove it it worked perfectly but later the same day
> it started acting up again and still is not right. Can anyone give me some
> advise. I am thinking that it could be the electronic shifting control
> module, but I know nothing about this, Thanks
>

Freind bought a 1975 cherokee off ebay, the seller said the tranny was
shot, same symptoms as you disscribe, I went with freind to get cherokee, he
changed the $9.00 tranny filter and away it went

"davees90JEEP" > wrote in message
lkaboutautos.com...
> My Jeep cherokee 4x4 has an automatic transmission with overdrive.The
> problem I am having is with the transmission not wanting to shift. In
> order for me to get it to shift i litterally have to wind the engine out.
> It shifts from low to second gear at 35 mph and then will not shift into
> the next gear until you reach 65 mph. It seems to be intermittant as
> yesterday when I first drove it it worked perfectly but later the same day
> it started acting up again and still is not right. Can anyone give me some
> advise. I am thinking that it could be the electronic shifting control
> module, but I know nothing about this, Thanks
>

The shift points are somewhat controlled by the throttle position
sensor. The plug and socket on it get corroded. I clean them with a
spray contact cleaner, then use some dielectric grease on the plug seal
skirt which seems to last at least a couple years.

WD40 will also work as a cleaner in a pinch, but the job doesn't last
long.

If cleaning doesn't help, then you can test it with a multimeter. On
ohms, it will vary the resistance going up on the center wire and one
side wire, and vary going opposite on the center wire and the other side
wire. The resistance must be smooth.

There are voltage tests for it too. You have the engine key on run and
backprobe the plug. The voltage should go from .02V to 4.8V. Same deal
as above, one side goes up from .02 and the other side goes down to
0.02V and it must be a smooth transition.

Hope this helps,

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

davees90JEEP wrote:
>
> My Jeep cherokee 4x4 has an automatic transmission with overdrive.The
> problem I am having is with the transmission not wanting to shift. In
> order for me to get it to shift i litterally have to wind the engine out.
> It shifts from low to second gear at 35 mph and then will not shift into
> the next gear until you reach 65 mph. It seems to be intermittant as
> yesterday when I first drove it it worked perfectly but later the same day
> it started acting up again and still is not right. Can anyone give me some
> advise. I am thinking that it could be the electronic shifting control
> module, but I know nothing about this, Thanks