95 grand cherokee od light stuck in third

terry3blue · 01-05-2010, 07:25 AM

Ive had the governor switches replaced, but heres the problem. when its cold like 25 or below when you crank it in the mornings the od light stays on and the trans is stuck in third after you drive it about 10 miles and cut the vehicle of the light goes off. It wont come on every morning. Ive also noticed that if i leave the heat selecter switch on it does it all the time, but if the selector switch is in the off position it dont do it as much, sounds crazy i know but it semms to be involved. Its a 95 jeep grand cherokee with a 4.0 and 4 wheel drive. Im new here and i have searched the forums but havnt found anything, im running out of options so thanks for any help.

JS97ZJ · 01-05-2010, 02:44 PM

i doubt that the heater control has anything to do with the overdrive circuit. The od switch goes directly to the PCM. The switch is a momentary type, hit it once, it turns off the over drive seleniod & turns on the lamp. Hit it again tells PCM to re-energize the selenoid & turns off the lamp. I would suspect the switch. Pull the switch & check for continuity it should only read when pressed. I had a car that when it got extremely cold the horn would turn on. Steering wheel horn switch pad was bad.

**ratmonkey** · 01-05-2010, 03:38 PM

could be a short in the wiring, sounds like the gov pressure sensor/temp sensor is bad though.

terry3blue · 01-05-2010, 09:49 PM

if it was the switch wont it still have 1st and 2nd gear, it only has 3rd when light is on.

**Virmagicus** · 01-05-2010, 09:56 PM

When the OD light comes on can you turn it back off when it is stuck in third?

terry3blue · 01-05-2010, 10:09 PM

no it stays on till i drive about 10 minutes then pull over and cut the jeep off and crank it back up and it wont be on then.

**ratmonkey** · 01-05-2010, 10:36 PM

Its in limp mode. You will not have any gear other than 3rd. Sounds like it needs to warm up before you can drive it.

Driving it while in limp mode will kill the transmission very quickly. Find the problem before you need a new tranny.

terry3blue · 01-06-2010, 06:03 AM

ive tried warming up for 15 or 20 mjnutes but it didnt help either, my tranny mechanic said the tranny fine, hes one of the best in my area. i was wondering if it could be in iginition switch. Its gremlin, has to be.

**ratmonkey** · 01-06-2010, 07:06 AM

warming up the engine doesn't do anything for the transmission, which is what i was saying needed to warm up before functioning right. i think you have a bad gov pressure/temperature sensor(same unit).

try warming up the jeep while the tranny is in neutral and see if that does anything for you(the tranny won't circulate fluid unless it is in a drive gear or neutral).

baxy · 01-06-2010, 07:10 AM

the software that controls the transmission is programmed not to allow 4th gear if it thinks the trans is too cold

common complaint when I worked at the dealership with jeeps and dakotas

I'm sure there is a TSB explaining it , also chrysler offers a software update which will allow 4th when it is cold but it comes with a warning of possible trans damage

**Virmagicus** · 01-06-2010, 08:10 AM

I believe it goes by coolant temperature though before shifting into 4th. It gets real cold here as well and i notice this all of the time but the light never comes on, it will just act like the OD is off until the coolant reaches a certain temp. I am guessing around 120ish. And the OP does not have 1-2 shifts, only 3 until warm.

terry3blue · 01-06-2010, 08:11 AM

tranny guy pulled codes today it had for gov sol, torq convert circuit, od circuit. I think im haven a problem with the power supply feeding these switches but i dont know where the supply comes from like ign switch, pcm, or tcm.

terry3blue · 01-06-2010, 08:15 AM

respond to above about o/d waitiung till its warm. I dont have 1st or 2nd either till it warms up.

**ratmonkey** · 01-06-2010, 08:49 AM

Quote:

Originally Posted by terry3blue

respond to above about o/d waitiung till its warm. I dont have 1st or 2nd either till it warms up.

then you have a bigger problem.

check the relays in the power distribution center.

check the wiring to the main tranny plug for any worn through wires.

after that you can start digging into the transmission valve body.

terry3blue · 01-06-2010, 09:36 AM

thanks for the help i have a feeling its going to take a while to trace this one down, but atleast i have a starting point.