My AWD Build Thread

[jkohnz]

HI! I'm new to the forums, and will be looking to find a 67-72 GMC short bed, fleetside C10. I already have a lot of plans for it, and have been browsing these forums for a few weeks now before registering. I've seen some impressive builds here!

My current plans are using a 2002 Cadillac Escalade AWD chassis that I picked up pretty cheap on Craigslist locally. It came with everything but wiring, for the most part (pic to be attached later). I actually hadn't planned on building anything just yet, but happened to see this while looking for something else lol.

I've seen a few builds on here using Suburbans and Tahoes. I want to use the 6.0L + 4L60E that comes in these, but don't have them yet. I would rather not modify the NP149 transfer case if at all possible. Eventual plan is twin aft turbos, lowered 2" front, 3" rear on the chassis, and have a "hotrod" sport truck to tool around in. It's going to be a very slow process for me while I do research and make room for the project.

My first step is cleaning up, media blasting, and prepping the chassis. Then, once I'm caught up with all that, I'll be looking for a donor vehicle for the engine, trans, wiring, maybe even the floor and firewall.

[jkohnz]

My chassis, needs "some" TLC...

[sick472]

Welcome from a near neighbor (Sedalia Mo). Your project sounds very cool! I'll be looking for your progress reports.

[jkohnz]

So I'm at a bit of a conundrum. I don't know a ton about AWD. I talked to the guy at RS Gear, and he says I should drop the NP149 t-case and go with a BW 4473 (because I'm thinking hard about the T56 he has with the t-case). But, I've read a lot on the 4473 and how they've failed a lot due to poor lubrication. I haven't found as much about the NP149 being problematic, and I know they come in the Silverado SS's, Escalades, Denali's, etc.

Anyone have experience/valid opinions on this?

[mike16]

I'm a bit old school. is AWD anything like 4x4?

[jkohnz]

Originally Posted by mike16

I'm a bit old school. is AWD anything like 4x4?

4X4 has 100% power to the front wheels when the vehicle is put into 4X4, and it's not full time. the transfer cases are not built for full time to the front and will eventually grenade if you drive full time 4X4. The front diffs only lock when put into 4X4.

AWD has a power split, generally 38% front, 62% rear +/-. The have either clutches or viscous couplings in the transfer cases. The front diffs are full-time locked at all times so that the transfer case is under load and doesn't burn up.

[mike16]

Originally Posted by jkohnz

4X4 has 100% power to the front wheels when the vehicle is put into 4X4, and it's not full time. the transfer cases are not built for full time to the front and will eventually grenade if you drive full time 4X4. The front diffs only lock when put into 4X4.

AWD has a power split, generally 38% front, 62% rear +/-. The have either clutches or viscous couplings in the transfer cases. The front diffs are full-time locked at all times so that the transfer case is under load and doesn't burn up.

"I am an old dawg and these are new tricks"

[palallin]

Originally Posted by jkohnz

4X4 has 100% power to the front wheels when the vehicle is put into 4X4, and it's not full time. the transfer cases are not built for full time to the front and will eventually grenade if you drive full time 4X4. The front diffs only lock when put into 4X4.

Uh, no. Most (but not all) xfer cases transmit power equally front and rear as long as all tires have traction (or both axles do, if limited slip or lockers). 100% power to the front axle would mean no power to the rear.

Further, there are MANY xfer cases designed for full-time 4WD, the old school NP 203 being one example. Internal differential action allows them to go on any surface all the time. And the part-time cases are only stressed so long as all tires have traction (or both axles, if limited slip or locker) on solid pavement or other hard surface. As long as there is some slip, you can drive them full-time. In fact, so long as you don't turn, you can drive them full-time on hard pavement. It's the lack of differential action that causes them to bind and eventually over stress.

[jkohnz]

Originally Posted by palallin

Uh, no. Most (but not all) xfer cases transmit power equally front and rear as long as all tires have traction (or both axles do, if limited slip or lockers). 100% power to the front axle would mean no power to the rear.

Further, there are MANY xfer cases designed for full-time 4WD, the old school NP 203 being one example. Internal differential action allows them to go on any surface all the time. And the part-time cases are only stressed so long as all tires have traction (or both axles, if limited slip or locker) on solid pavement or other hard surface. As long as there is some slip, you can drive them full-time. In fact, so long as you don't turn, you can drive them full-time on hard pavement. It's the lack of differential action that causes them to bind and eventually over stress.

Yeah, I actually knew most of that. Mondays... Should have known better than to blanket statement ALL 4X4. Thanks

At any rate, I really need to know about the NP 149 vs. BW 4473.

[jkohnz]

Thought I would mention I found a good deal on a quality engine/transmission/wiring/ECU flashing at justchevytrucks.com. I've been emailing with Stu there the last few days, and his recommendations are pretty good stuff. I'm not ready to pull the trigger yet, but I'm looking at $4400 delivered for a fully tested 6.0L LQ4 with 156k miles, customized harness for stand alone, flashed ECU, and a fresh performance built 4L65E trans. Trans has 2yr 24k mile warranty to boot. Thought I would pass it along for others looking.

[Overdriven]

This board has newer GM truck sections as well, might want to check out those sections for more info on the newer drivetrain stuff. I know LS1tech has more than a few that have gone turbo on their newer Tahoes, burbs, Escalades, etc. They would know what holds up and what doesn’t.

[jkohnz]

Finally got my truck. 68 C20 long bed. Running truck. 6cyl 4 speed, bed shot, but can in fairly good condition. Clean title. Only paid $800.

[jkohnz]

Can't believe it's been over a year since I started this thread. As with many others have had happen, a lot of life has caused delays on my project. But, there has been a tiny bit of progress.

Plans are still close to the same, except I've decided to go stepside instead of fleet.

My C20 is sitting in my garage with the junk bed, and the partially good front clip, removed. I was able to get a good deal on a freshly media blasted core support that has also already had the usually rusted out section repaired quite nicely. I picked up a used GM left fender recently as well for a good deal.

I also recently picked up a 2004 GMC Yukon Denali to complete my project with. I found that the first chassis I picked up had probably $2k in suspension and steering parts needing replaced, as well as some questionable rust spots. But, for the price I paid for it, I'm not unhappy. I did get a front and rear axle, as well as the NP149 transfer case. The Denali has a newer case that won't work as well for my project. I also figured I could drive the Denali around while I pick up parts and finish up planning.

As for the first chassis, I figured I could get my 68 cab removed and set on it, work on mocking up mounts, tack them in place, etc. Then, when I'm ready to do the swap, take it all off and put it on the Denali chassis.

Finally, I picked up a nice set of 20" wheels and got a heck of a deal on new tires to boot.

Some pics of what's going on...

[68 P.O.S.]

That's gonna look nice!

[jkohnz]

Picked up a short step bed over the weekend. Slowly getting my parts together!

[jkohnz]

Some recent updates...

Got my cab, fenders and hood media blasted. Cab had a little more rot than I had hoped for, but it's manageable. Going to have to replace the outer roof panel now, as I found some hidden rot inside the cab on the roof and such, and patch both seems on the bottom of the windshield and around the wiper motor. Amazing how many small dings and dents someone had filled on this thing. The hood has a few pin holes on the front edge, and a football sized section where someone "fixed" a dent.

I've picked up replacement cab corners, outer rockers, and full floor. Still need the roof panel and some sheet metal to fab up the bottom section of the back of the cab between the cab corners.

The 04 Denali started losing a lot of oil and coolant, so I decided to park it, tear it down, and part it out. Now I'm focusing on lining up the cab and bed on the 04 frame. In order to get the bed to roughly fit, I had to cut 4 inches off the rear frame rails and cut off some of the body mounts. I notched the spare tire mount for the rear cross brace for the bed also. I also did some cutting on the bed as well.

I've also decided to use my center console and 2nd row buckets from the Denali, I set them in the cab, and they fit pretty good. I'll just need to rework the seat brackets to fit the floor some, but they feel real nice sitting in the cab. Plus, they're heated. No need for power adjustments at all. Sits perfect for me.

[jkohnz]

More pics...

[CarlsLQ9SS]

From my experience, the np149 is very durable and dependable.

[jkohnz]

Originally Posted by CarlsLQ9SS

From my experience, the np149 is very durable and dependable.

Thanks for the input! I posted that a long time ago and have decided to stick with that TC. I have the BW one from the Denali still sitting here, but don't plan on using it.

[saon]

tagging along.
i too picked up a "06 SS truck and contemplating doing the same thing.
i was thinking about just using the front middle of the SS frame and splicing it into the 67-72 frame. i could Z it to set ride height low. interested to see how yours comes along.

[yuccales]

That's coming along great.

[SCOTI]

Tagging in to see future updates. Cool project!

[Ol Blue K20]

Subscribing to watch!

[jkohnz]

So, I've had some minor set backs since my last post - mainly time to work on it. However, my shop that was built in December 2019 has a massive humidity problem (sitting at 80% today). So, my leather seats, shelving units, anything made out of fabric or cheap wood, is covered in mold. Found this a little over a week ago. Waiting on a big dehumidifier to come in on Monday, so that I can start drying it out in there. Meanwhile, I'm going to be cleaning stuff. My cab is getting surface rust as well. So... yeah. Fun times.

[SCOTI]

Originally Posted by jkohnz

So, I've had some minor set backs since my last post - mainly time to work on it. However, my shop that was built in December 2019 has a massive humidity problem (sitting at 80% today). So, my leather seats, shelving units, anything made out of fabric or cheap wood, is covered in mold. Found this a little over a week ago. Waiting on a big dehumidifier to come in on Monday, so that I can start drying it out in there. Meanwhile, I'm going to be cleaning stuff. My cab is getting surface rust as well. So... yeah. Fun times.

Uhmm…. Yuck.

x2.