I just my 6.0L/4L80E swaped into my 1990 truck and now the tranny won't shift out of first gear, it goes into gear just fine forward and reverse but won't shift. I didn't know if this could be an electrical issue since the transmission is electronically controlled? anyone else have similar issues?
The motor and trans only have 31K miles on them.
Sounds like you do not have power to the transmission. The pink wire going into the connector should have power going to it when the brakes are not being pressed. First, pull the connector at the trans and probe it with a test light to see if you have power.
See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709
The pink wire showed power to it. What else could be causing this? The speedo doesn't work and I have read where this will cause problems in the newer trucks with keeping them from shifting. Is there any truth to this? Could this be keeping mine in limp mode?
In HPT, tuning the trans. 2 conditions have to be met in order to shift.....rpm and speed. I believe you may have found your problem unless you are controlling the trans. by some other means than an updated PCM and I am assuming you are using a PCM for a 4L80 or at least one with a segment swap for one.
Yeah, if the speedo doesn't work it won't shift. It may shift but not til redlinish and when it does it will clunk really bad.
2013 CC 5.3
81 C10 LS1 project
Yes on the PCM I a running a complete pullout from an 06 in my 90. motor trans, harness, PCM
Also on the speedo part the other threads I have found show to hook the wires from the speedo and tap them into the wires on the VSS. What should the wire that goes from the PCM to the speedo in a factory setup be hooked up to?
Currently the speedo is just wired to the PCM pinout for the speedo and that doesn't work.
Last edited by scarbrow; 09-21-2009 at 01:20 PM.
the output doesnt work because you're not getting feedback, most likely. Do you have HPTUNERS software or something like it?
See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709
I personally don't have HP tuners, I had another guy from the area turn off the VATS and rear O2's for me using HP tuners.
I was wondering if maybe you could get him to scan it as you drive to see if its reconginising the speed in the PCM. It would be good to look at your tune to see if the PCM was for a 60e or 80e. PCMs get swapped all the time and this could be the issue as to why its not working properly.
See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709
^^Ask G about this. His 80 wasn't shifting right at all until he got the tune worked out.
1969 Chevy RCLB C10 350/TH400 SOLD
2007 Chevy RCSB 4.8 4x4 LS SOLD
2008 Chevy RCSB 5.3 4x4 LT SOLD
2010 Chevy CCSB 6.2 4x4 LT SOLD
2005 GMC CCLB DRW 6.6 Duramax 4x4 191,000 and counting
2013 FORD CCSB F350 6.7 Powerstroke 4x4
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