transmission not shifting

2006 CHEVROLET 2500
280,000 MILES • 6.0L • V8 • 4WD • AUTOMATIC
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ERIK GUTIERREZ
  • MEMBER
  • 2 POSTS
transmission not shifting can only go up to 55 and RPMs go all the way to 4,500. found out that my IGN O FUSE was popped refers to TCM replaced that and try to turn it on but will pop fuse even if you only turn key forward. i went ahead and replaced ignition switch and still does same thing on popping fuse. can someone help me on this problem?
May 26, 2021 at 10:30 AM
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JACOBANDNICKOLAS
  • CERTIFIED EXPERT
  • 110,175 POSTS
Hi,

The fuse you indicated is what powers the torque converter clutch. That would explain why you had high RPMs at the speed you mentioned.

If you look at the pics below, they are the wiring schematics for the transmission circuit. I highlighted the wiring related to the fuse you replaced.

If the fuse blows as soon as you turn the key to run, there has to be a short. According to the schematic, that fuse runs back to the underhood fuse box. I circled that point in the pic. Check that to see if there is a short.

Start with this and let me know what you find. Also, here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

I will watch for your reply.

Take care,

Joe

See pics below. Note: I had to cut the pic in half to make it readable. I did overlap them so you can follow from one to the next.

Images (Click to enlarge)
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May 27, 2021 at 9:03 PM