Will's Bug Out Rig: Duramax Van

[The Dark Side of Will]

The van never had much paint on the roof. It grew up in Tucson and 2000's GM white was no match for Arizona sun and dust storms.

Over the weekend I had a local dude pressure wash the roof to remove any remaining paint, then I applied POR-15's zinc phosphate metal prep, so that I can paint the roof at some point in the near future.

I did not get good before/after photos. Here's the van when I drove it to work Friday



Here's the zinc phosphate application after I got it back to my house.





The apparently rusty area is NOT a miss or gap in coverage. I'm not sure if the white is excess or how the treatment actually works. The apparently rusty areas definitely have a clear coating over them.

I'm looking for a 2k urethane roof paint in Ugly Industrial Beige. That way if I park it on bare dirt, it's a lot harder to find in overhead photos. Being a light color, it will also be cooler in summer. My dad has some aluminized roofing paint, but that's aluminum colored, not bare dirt colored.

Also starting to look for a different year/application of brake lines that would make getting into my underhood fuse box easier. After I finish The Mule's harness, my next wiring project will be a factory-style trailer wiring harness for the van. The factory trailer harnesses are pretty awesome, in that they include provision for a brake controller as well as relays to operate the turn signals so that the flash rate stays normal, no matter how many lights are on the trailer.

[The Dark Side of Will]

I had an idea for how to test an Allison TCM (A40 or A41, IIRC) in my van.

As we discussed above, adding one to the bus in addition to the T42 already there would cause bus collisions and lots of problems.

The 4L80E is in 2nd gear with both shift solenoids de-energized. The pressure control mechanism goes to max line pressure when the pressure control solenoid is de-energized. The gear selector is mechanical, and of course the TCC lockup stays unlocked when the solenoid is de-energized. The transmission can be driven in 2nd gear unlock with max line pressure with zero electrical inputs.

So I can build a break-out harness adapter that allows me to plug an Allison TCM in place of my T42. The break out adapter would not connect the shift solenoids or the pressure control solenoid, and may have other features like giving the Allison TCM resistors and/or LEDs instead of the Allison solenoids. I could use an Allison range switch and add other features to make it a "live" testbed. I could drive the vehicle in a limited fashion in 2nd gear, record what codes are set, maybe sniff bus traffic, etc. And then just remove the Allison TCM + break-out adapter, plug the T42 back in and drive the van normally.

Sure beats doing a swap that I can't get to work right, then undoing the swap to put it back to stock.

[Series8217]

Do you know anyone with an Allison in a working vehicle that you could install a CAN logger in for a bit? Just need a few conditions.. stopped, engine off. Start engine. Idle. Put in drive and stand on brake for a few seconds. Drive off at steady slow speed first gear. Then a gradual acceleration up to highway speed and back down. A log of the powertrain CAN for that drive cycle should be enough to reverse engineer the messages needed to make the TCM happy.

[The Dark Side of Will]

Do you know anyone with an Allison in a working vehicle that you could install a CAN logger in for a bit? Just need a few conditions.. stopped, engine off. Start engine. Idle. Put in drive and stand on brake for a few seconds. Drive off at steady slow speed first gear. Then a gradual acceleration up to highway speed and back down. A log of the powertrain CAN for that drive cycle should be enough to reverse engineer the messages needed to make the TCM happy.

I don't specifically, but I should be able to find someone.

Yes, before I go to the trouble of building a break out adapter, I would want to do bus sniffing on both vehicles to see what the bus traffic looks like. Maybe more than "both"... I certainly want to try a 2006 Silverado Duramax, but maybe also a 2006 Topkick Duramax (good luck finding one!) and a 2006 Silverado 8100/Allison. I'd love to try a 2006 Hummer H1 Alpha, but not likely to find one