The last hurdle was the fuel pump for the AFM and associated wiring don't work with the new wiring harness. Rather that replacing the body harness we hot wired the fuel pump to be on when the ignition is on.

So other than the obvious hard parts, just get a wiring harness for a 6sp and if your truck HAD AFM you'll have to work around the fuel pump issue.

Good Luck...

 

Looks like MNC5 found an AFM issue I hadn't though of. Check out post #31.

 

You mentioned something about resonance in 4 cyl mode with the tc locked up.

I dont know if it is my tc unlocking but right before my truck goes into 4 cyl mode the revs seem to come up 100-200rpm. Does this have to do with the tc unlocking before to stop harmonics or because the engine needs a few more revs at highway speed in 4 cyl mode??

MNC5, in your case Did you start with an AFM truck?

 

Yep, I had already scrapped the AFM due to a cam install. Mine is a 6.0 liter

 

so when are you gonna post up a how to and what parts you used, i want a 6speed in my 4door bad

 

How to... I already posted it

Buy the obvious hard parts 1. You'll need a wiring harness from a 6sp truck 2. Reflash your ECM with a 6sp vin 3. I had to hot wire the fuel pump as mine was a AFM vehicle. 4. The rest, well if you can't figure it out you shouldn't attempt it

 

Questions:

1) Does the dash cluster work properly, does the tranny gear readout work?

2) Did you use the factory engine/tranny wiring harness or did you have one made?

 

1. I haven't replaced the cluster. It does light up PRND pulling the shift lever down further results in a code.

2. Had SpearTech make one, but didn't use it. I went with a new factory engine harness because its the one that has the correct plug for the tranny.

3. I'm still having fuel issues. I hot wired the fuel pump and have 90+lbs of fuel pressure currently. It might be easier if you started with a non AFM vehicle.

 

Thanks for the info. I took a look and there are two fuel pump setups for these trucks, but AFM does not appear to be the deciding factor.

LMG (5.3 flex AFM), LC9 (5.3 AFM) and LY6 (6.0L without AFM) use one system (ecm decides when pump is on).

The rest (LH6, LY2, LY5,L76, and L92) use another and three of those 5 engines have AFM. On that one there is a fuel pump flow control module.

Weird

 

Just an update, the difference might be flexfuel. The LMG and LC9 are flexfuel, but can't find any info on the LY6 (to confirm theory). The rest are not.