I HAVE A 2004 GMC 2500HD W 8

  • Tiny
  • Anonymous
  • 2004 GMC Truck
  • 106,000 miles

I have a 2004 gmc 2500hd w/ 8.1 l and allison trans. Scanner says the trans is losing communication. While driving it intermittenly loses cominication causing spedo to quit, the eng light comes on, also the park brake light and abs light. This only happens periodiclly and only lasts for few seconds and back to normal. Have already changed ignition switch cuz all the components involved run through the switch. Still does it. Transmission modular?

Tuesday, January 22nd, 2013 AT 11:33 PM

1 Reply

  • Tiny
  • ASEMaster6371
  • Expert
  • 25,556 posts

It all runs through the pcm and tcm as we. I would look at connections first before assuming anything else.


Was this
Wednesday, January 23rd, 2013 AT 2:14 AM

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