03 lb7 trans problem

nasty03

New member
Feb 12, 2013
6
0
1
concord nc
I have a 03 lb7 4x4 with built suncoastwith 1057 3D converter, trans has never had a problem has around 15k, I went to crank the truck and it won’t move just revs up, checked codes and there are none..so I replaced the nsbu switch, no help. I Then checked the wiring and replaced the whole wiring harness no help, I can remove the Big electrical plug on back of trans and the trans has 3rd reverse and park plug back in and has nothing. So I then removed the pan and checked the internal filter wiring etc all fine replaced filter while I was at it, put back together filled with fluid and still nothing. I removed the pressure test port on trans by the filter and fluid sprays out like crazy so guessing it has pressure I don’t have fitting to put a gauge on but it sprays like crazy.
there are no codes and I’m at a lose, I have been trying to find out the issue for couple weeks now researching online and trying things and finally I am asking for help,
Any help would be appreciated

I checked all pin outs on wiring when I replaced everything checks out. I have efi live and reflashed the tcm and still no luck,
 

nasty03

New member
Feb 12, 2013
6
0
1
concord nc
Ok so I went under the truck unplugged the big connector and checked voltage with key on I have 11v on some wires and 5/6v on other wires crank truck I have 13v and 5/6v
I have changed the harness and the tcm out still same symptoms
 

nasty03

New member
Feb 12, 2013
6
0
1
concord nc
I believe I might have it fixed finally, So after I changed the ignition it did the same thing but was getting voltage to trans cleared all modules and reflashed and it started working
Going to test drive tomorrow and hopefully all is good..

Thank you for the input I would have never thought the ignition module would have controlled voltage to trans
 

ironmax

chock full of goodies
Jul 6, 2010
455
4
18
Col. Ohio
I believe I might have it fixed finally, So after I changed the ignition it did the same thing but was getting voltage to trans cleared all modules and reflashed and it started working
Going to test drive tomorrow and hopefully all is good..

Thank you for the input I would have never thought the ignition module would have controlled voltage to trans
Good to hear, we like feed back around here. It helps other people with similar issues so the same questions don't get answered over and over again.(y)
 

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