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Discussion Starter · #1 ·
Hello all. I have been trolling this site for a while, and I'm just now registering to ask a question.

I have a 1995 Jeep GC, I6, automatic, full time 4WD, w/ 124K miles.

This issue just started 2 weeks ago.

When I first start the engine, either in the morning or afternoon, the OD light comes on, stays on, and the Jeep will not shift into first.....it starts off in second, even if I manually put it into first. If I turn off the engine, wait a second, restart, then the OD light will go off, and the Jeep will start out in first, and everything is OK.

From reading past posts, when the OD light starts coming on at random times, the tranny is about to go.

I just had the tranny serviced the day after the light started coming on. The mechanic said he found no metal pieces when he flushed the system..

Do I need to start looking for another Jeep? Do I need to get a new tranny? What is the ballpark costs of that?

One more thing, I just got back from a weekend road trip of 800+ miles with no issues. (no shifting out of OD at highway speeds)

Thanks
Michael
 

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could an electrical problem. try the output speed sensor, which is located on the bottom driver's side of the tranny; or it could be a vehicle speed sensor, located on the tailshaft of the tranny-transfercase. those two sensors have been known to give some people problems. Your tranny is electronically shifted, so shifting issues may have to do with electronics rather than internals.

if your OD light comes on at the start-up of the Jeep, then it isn't internal. Usually when the OD light comes on when you're driving, and won't go off, that is a sign the tranny is overheating. But if the light comes on at start-up, then how can the tranny be overheating?! you see my point. also try the transmission temp sensor. these tranny's are tricky, so goodluck.
 

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I think the OD stays off when its really cold as well. Not sure what the outside temp is there but I have had mine in some pretty cold weather and it has never done it.
 

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The tranny is computer controlled.
The OD light is the tranny equivalent of the Check Engine Light
There is an onboard diagnostic system and the computer runs through its routine everytime you start the engine.
You can check for stored fault codes exactly the same way you would pull engine codes with the key on-off routine.

The OD light .. count the blinks
Code:
example:
blink blink pause blink blink blink = 23

23 = converter clutch solenoid ouput
My guess is that because a) the problem is transient and b) the light is on that the solution will be somewhat less catastrophic than a complete rebuild. That little 42RE is a pretty tough unit, unfortunately saddled with a ton of electronic bells and whistles that stop there ding-dinging and toot-tooting.

:lol:
 

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Sorry if I'm hijacking this thread but, my OD light doesn't come on at all, and although my transmission has been shifting fine and done this for quite a long time with no problems, other than the non-functioning manual override + the light not working ever, I still do NOT get any trouble codes at all. It's as if all is as it should be when a scan is performed. So whats that all about?

I figured something should show up at the least. Should I count my blessings that I'm free of this nagging feature or just worry my f'ing head off?
 

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pk,
my guess is the circuit betwen the switch and the computer is 'open' and the computer doesn't know the switch is being pushed, therefore it doesn't show any faults. The light is 'lit' by the computer after it receives the 'signal pulse' to switch off the OD. No signal pulse, therefore no light...

It can be something as dead simple as the harness connector is not plugged into the switch. Or maybe the ground connection is bad (the signal pulse is a 'ground' pulse) Or as hard to track down as an internal break in the wire somewhere. Unplug the TCM connector, probe the pin socket coming from the switch, push button should give continuity to ground.

I wouldn't worry that your tranny will fail, but you should avoid towing heavy loads where the recommendation is to disengage OD to prevent excessive shifting. And when you have some time get a meter and a test light and begin tearing apart your dash to track the wires and find the fault.

hth
 

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Discussion Starter · #8 ·
Update on the OD/first gear issue..

It seems to only have problems when it is cold outside (<40F). Once the temp drops, I cannot even turn off the engine to get the OD light to go off.
Also, the OD light stays constant. It does not flash.

Since it has been warm here in Arkansas the last few days, I have not been able to check the codes for any problems. The 'check engine' light just flashes 5 - 5. Which means all is well in my Jeep book.

Since it is temp dependent, I'm thinking its a bad sensor or connection.

I found where the VSS (vehicle speed sensor) is supposed to be, but I've found nothing in my jeep book about an output speed sensor.

I guess I'll update ya'll when the temp drops.. (not likely until 11-24). Damn this warm weather!

Michael
 

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I saw you posted this year's back. My Jeep is now doing the exact same thing so I was wondering if you found a solution to this?


I have a 1995 Jeep GC, I6, automatic, full time 4WD, w/ 124K miles.

This issue just started 2 weeks ago.

When I first start the engine, either in the morning or afternoon, the OD light comes on, stays on, and the Jeep will not shift into first.....it starts off in second, even if I manually put it into first. If I turn off the engine, wait a second, restart, then the OD light will go off, and the Jeep will start out in first, and everything is OK.

From reading past posts, when the OD light starts coming on at random times, the tranny is about to go.

I just had the tranny serviced the day after the light started coming on. The mechanic said he found no metal pieces when he flushed the system..

Do I need to start looking for another Jeep? Do I need to get a new tranny? What is the ballpark costs of that?

One more thing, I just got back from a weekend road trip of 800+ miles with no issues. (no shifting out of OD at highway speeds)

Thanks
Michael
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