davester

It can also be an exhaust leak. Check that all the bolts are present on the exhaust manifolds (they are prone to breaking off over time).

Yes, at least the '04 version is, but it's unlikely the '05 version changed that much. The grille goes around the headlights and marker lights anyway... It's been awhile since I've had to remove it, but I believe the grille has pins that pull out (w.r.t. the truck, pull forwards) at the ends [there are more pins in the middle, and a screw you need to remove as well], but you need to unclip the strip from the fender liner first, as it clips on sideways. And that strip only has clips on each end, the rest of it is supported only by the grille.

Don't know the name, it's the strip to cover the gap caused by the 2" body lift. GM probably doesn't have it anymore (and it would be ridiculously expensive if they did), probably the most reasonable place would be a junkyard. I'm not sure how easy it is to detach from/attach to the main grille, as every time I've removed the grille from my truck, this strip has remained attached to the grille.

Good luck with getting a shop to remove the old TC and install the new one for $100. Having done this twice myself, with a well equipped garage other than having a lift, and it's not a 1-man-hour job, even with a lift.

Given that the dome lights come on & off proper with the doors, that indicates the BCM is correctly getting and processing the doors opening/closing, I would look at the crutchfield-supplied wiring harness, as that harness should/will have some circuitry to get the RAP signal from the serial bus and then turn on/off power to the radio based on that (there's also be a separate always-on power supply to the radio for the clock and to keep radio settings). After 10 years, it's possible something has failed in that circuitry.

I'm also pretty sure that you just use 'regular' atf fluid in the transfer case, the same as a manual transfer case. Auto-Trak II fluid is for the AWD/always on transfer case, which I don't believe is available on the 2500hd/3500 trucks. It's probably fine to run with the Auto-Trak II fluid, it's just not what GM recommends and much more expensive than regular ATF.

Normally, I go for the bellhousing bolts with a short socket (or a long one if they are also studs), an impact swivel (so it can angle a little, but not all over the place like a non-impact swivel), a really long extension (2+ feet long) and a ratchet and go at them from the rear of the transmission. It was easier to do on my truck ('04 Sierra 3500, which has a 2" OEM body lift) than it was on my car (78 Impala). It might also be easier to remove/install the engine and transmission as a unit, and then separate them once removed from the truck. And instead of getting a fire-starter, do a short subscription to alldatadiy.com for the truck instead. It will have WAY more detail on that specific truck vs the mostly generic info in the cheap Haynes/Chilton books.

Or find a wrecked one in a junkyard. Cheaper and you can get all the parts you need in one shot.

It's near the dash brace going to the transmission hump on the drivers side. You need to remove the cover/shield running along the middle of the dash (along the underside of the dash). It's fun, several blind bolts that you need sockets just the right length to do them... There needs to be two, so the two side can have different temperatures.

There are two blend door actuators (so you can have separate passenger/driver temps). Which did you replace?

Bolt pattern for the cover on the rear diff should tell you, but most likely you have a 10.5" rear axle.

What do you mean by "can't pull codes"? Does it report an error trying to get codes, or just that there are no codes?

That's hilarious. GM designed, built and sold it before Obama even began running for President.

The XHD version must be different, as I was pretty sure my 261HD had one that worked as I described (you have to make it smaller to remove it), and I re-watched the assembly youtube video I worked off, and it was definitely that way... But it's great that you got it out.

The seal might be pressing against the bearing on the other side, pushing it against that clip. You might try removing the seal if you haven't already. Or just tapping the bearing away from that clip (only tapping/hammering on the outer edge).