Quick question, the park/neutral position switch appears to tell the PCM what gear the transmission is in (according to the wiring diagram). Does the PCM alter the tune or anything else depending on which gear the transmission is in?

The reason I ask is because I'm putting a T56 into my '01 Silverado and can ground the wires of the PNP switch to make the truck think it's in any gear. I have it wired right now to be in drive.

Thanks!

 

Did you look at the legendary T56 swap thread? I haven't read through that whole thing but I'm sure its covered in there.

 

No, that thread has nothing but misinformation about wiring. I'm planning on writing up the wiring section of it once I get things sorted out.

Hopefully tuners will know if the PCM will change anything in the tune based on what gear it's in as indicated by the PNP switch.

 

I take it back. I can wire the PNP switch so the gear indicator says DRIVE when it's not running, then as soon as the engine is running the gear indicator goes back to 2ND. Anyone know how to wire the PNP switch so it says DRIVE even when running?

 

Can't you just tell the PCM that the vehicle doesnt have a PRNDL switch so it references the in gear airflow tables all the time?

 

I would like to but I have no idea how. Now the gear indicator says 2ND even when the engine off. When I turn the key to run it goes to drive, pauses for a fraction of a second, then goes to 2ND. Before it would go to drive when on run, then go to 2ND when the engine is running.

 

Do you have any tuning software? HPtuners?

 

exactly what im trying to do right now on my 08' silverado,im trying to turn it on without the trans

 

I don't have tuning software. I sent Jim at CalSpeed an email about getting a mail order tune. Hopefully he will know how to tune for the T56. It sounds like you can turn off the gear display on the dash (I heard people calling it the "prndl") in the tune. Not to mention the half dozen codes because the PCM can't find its shift solenoids.

So far I'm loving the T56! Even with stock gears its a lot of fun. 4.56's and Truetrac are going in this weekend!

 

It can be fixed in the tune. There is an actual table that you can select either manual or auto trans..... I removed and dummy pinned all the auto trans wires from my harness. Weight reduction