Chevy and GMC Duramax Diesel Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
Truck Details
2008 Chevy 2500HD
Crew Cab 8 foot bed
No modification completely stock

So I am really scratching my head at this one. This all started about a week ago. I was driving down the highway around 70 mph and all of a sudden the transmission went into neutral I coasted to the side of the highway. The shift inhibited message was displayed on the DIC. No CEL was displayed and all gears acted like neutral. So I turned the truck on and off and disconnected the battery reconnected the battery then the truck went into gear only with the manual shift mode and with a horrible screeching noise for about a half of a mile before I decided to stop to prevent damage. Still no CEL. To this point I have done the following with no luck:

  • Checked the TCM for codes
    • None
  • Checked for collapsed pan filter
    • Filter was in tact, perfectly clean oil and no metal on the magnetic drain plug
  • Checked the main harness plug on the transmission
    • was coated in oil plug was clean and grease with dielectric grease
  • Checked TCM plug and pins
    • no loose pins
Any ideas I'm currently leaning towards a fried TCM any thought really pulling my hair out on this one. I will trade a six pack for the solution!!!!:p
 

·
Registered
Joined
·
1,757 Posts
Certainly LMM's do have faulty TCMs from time to time, but check the wiring harness carefully before you spring for a new TCM and programming, only to find out that your problem continues. The wiring harnesses between the transmission and the TCM have problems also and are much easier to repair, once the 'bad spot' is located. Take a look at this video
 

·
Registered
Joined
·
3 Posts
Discussion Starter #4
Certainly LMM's do have faulty TCMs from time to time, but check the wiring harness carefully before you spring for a new TCM and programming, only to find out that your problem continues. The wiring harnesses between the transmission and the TCM have problems also and are much easier to repair, once the 'bad spot' is located. Take a look at this video
Are there any key locations they fail or where would you start?
 

·
Registered
Joined
·
1,757 Posts
Are there any key locations they fail or where would you start?
If you watched the video, it shows you where this mechanic checked for problems. Start at one end of the harness and keep going until you find the problem or that the problems is elsewhere.
 
1 - 6 of 6 Posts
Top