Hi,

First off, thank you all for this awesome forum!


I have a 99 ml320 with 260K Miles on it. and this is the FIRST major problem it's given me.

I drove it yesterday for a good 200 mile and parked it at night, then when i went to drive it in the morning, i noticed that it was revving much faster and went through all five gear by the time it was going 20MPH!!!!!!!!!!!

Then i noticed that the low range light was on, so i pulled over, put it in neutral and hit the low range button to no avail, just 3 blinks and it was still on.

I came back home and disconnected the battery for 20 mins and turned it on again, still stuck in low range, then i got underneath it and told my friend to hit the low range button and nothing (no vibration or sound from the transfer case motor) i tapped the motor a couple of times with a hammer too, but nothing.

so i have come to the conclusion that either my transfer case motor is bad, OR my transfer case controller module is bad (if these cars even have one).

both are pricey. I was wondering if you guy have any troubleshooting tips to pinpoint the problem. help me please, the car gets about 6 miles to the gallon because of this. not to mention that i have to change the oil since its been revving soo much.

I'm a mechanical engineer and love working on cars, so DIY is not an issue for me.





P.S i scanned the ECM and the only relevant code i got was a 137. something about CAN not being able to communicate with the TCC


ANY INFO IS APRECIATED!!!

Thanks,
RAY

That code is your answer. The system cannot communicate with the transfer case controller. The motors on the transfer cases can go bad, not unusual (look at how it just hangs out there exposed to the elements, not surprising). It could simply be corrosion of the wiring outside the body down to the motor/connectors.

I checked the wiring while down there and they didn't look affected by the enviorment.




I have decided to check the voltages going to the motor, to see it actually receives signals from the tcc or not. i need the wiring diagram though, anyones got it?


thanks