Fool's Errand (Aeromodding GMC 2500HD)

[vskid3]

Had to take the top and front of the dash apart. Not really difficult, just time consuming. This is the guide I used. How to remove driverside/passanger side temp controll actuators in 04 Chevy Siverado I think it took 3 or 4 hours to take it apart, haven't put it back together yet.

[Deezler]

Nice thread and mods (thanks again for linking to it from my new thread) !

Originally Posted by aardvarcus

Also you can see the transmission crossmember hangs down below the frame about 2" for no reason. That can't be good for airflow down there. There are aftermarket flush ones available, or it wouldn't be that bad to fabricate.

I gotta agree here. The first time I got under my 2500HD I was shocked to see such lazy engineering by GM. $230 is a lot to swallow but I am now obsessed with this thing:

Transmission Cross Members By DJM At StylinTrucks.com

This is the only one I can find for a Chevy/GMC 2500. Anyone else know of other options?

Improved aero, better ground clearance, and "slightly moving the transmission, to correct driveshaft alignment" whatever that means. Is the factory alignment known to be poor?

With the low-pro crossmember it seems like you could get a nearly flat underside back to the rear axle, which hangs.... way down. Not sure if anything beneficial can really be done there to address/improve it and still allow for plenty of movement.

[Deezler]

Got it down to $218 with a coupon code on JC Whitney.... still too much.

http://www.jcwhitney.com/djm-suspens...545y2003g139j1

[vskid3]

I can buy a lot of gas for the price of that crossmember. I would consider it if I had a 4WD and took it wheeling, though. One way to reduce how much the rear axle sticks down is throwing a couple thousand pounds of whatever in the bed to squish the truck down a bit.

I got the dash put back together a while ago. Took 1-1.5 hours using the instructions to work backwards. I now have heat and cold on demand for both sides.

My dad's truck ('02 2500HD Duramax 4WD 4 door) wasn't liking to get very hot when winter rolled around. He stuck a coroplast grille block between the radiator and grille and it's been doing much better. About the only aeromod he's interested in doing. Kinda hard to get a picture of it, he cut out a hole for the tranny cooler to keep the tranny happy.

[Deezler]

Originally Posted by vskid3

One way to reduce how much the rear axle sticks down is throwing a couple thousand pounds of whatever in the bed to squish the truck down a bit.

I dunno man, I hauled ~2700 lbs of 12' drywall sheets and lumber for my buddy this morning and it barely squatted more than a couple inches! I was impressed.

Dunno if your dad has the allison or the 4L80 trans, but I've been monitoring my 4L80 temps on my scan gauge. It struggles to get above 100 deg F in calm driving when it's cold out, even with my grill block.

[Snowman9000]

I have about the same truck. Have you considered lowering it? Not street rod low, but two or three inches?

[vskid3]

I haven't considered lowering it because its main use is doing truck things, like hauling heavy stuff that squishes it and driving over things. Also, the cheapest kit I found in a quick search was $350 to lower the front 2" and rear 4" (which would probably still give me plenty of clearance). Would be a very long time for it to pay off with how much I drive it, even if it helped quite a bit.

My current mod is working quite well; it's driving the truck as little as possible. :P I last filled up over 4 months ago and I still have about 1/3rd of a tank left. I've only put about 2600 miles on the truck since I bought it about a year ago. Clearly even my cheap aeromods are more a labor of love than investments.

[vskid3]

Update on the truck:

Moved back in June, loaded all our stuff into the fifth wheel (it was completely packed) and drove from El Paso to Idaho. My dad flew down to drive the truck, as he has much more experience towing. He said the truck did great, the best towing gas truck he'd driven. It did 70-75MPH quite well, except for the steep hills. Even at those speeds, it didn't do terrible on gas. I reset the dash MPG gauge a couple hundred miles in and it showed 8.5MPG over the rest of the trip (at 13-14MPG, it's about .5MPG optimistic, not sure how it translates for lower MPGs). Weighed the whole setup and it was a bit over 16k lbs, just about at the GCWR, so the performance was great considering that.

Now to the current state of the truck... I sold it a couple weeks ago. Didn't need it anymore and it was just making my insurance cost more. I miss its roar, but I like being done putting money in it.