Chevrolet Express Van - AWD to 4x4 conversion

[Herbie]

Zuren, regarding your transmission-shifting-while-in-4LO issue:

Check out this thread on the AstroSafariVans site:
http://astrosafarivans.org/bb2/viewtopic.php?f=21&t=1940&hilit=switched+power

Read the whole thread for all the details, but the summary is this: On the Blazer and Astro/Safari TCUs, there's a pin that tells the TCU when 4LO is engaged that allows the shifting to work correctly. On the Astro/Safari TCUs, this pin is not connected BUT IS APPARENTLY FUNCTIONAL if you add a pin to the connector.

The OP on that thread solved the problem with a manual switch to ground the pin, but after more research, I believe that some of the NP transfer cases included a switch or sensor that closed (to ground) when 4LO is engaged, making it automatic. Even if your transfer case doesn't include the provisions for this switch, rigging up a microswitch that gets triggered by either by your shift handle or the shifting lever on the transfer case body should be fairly easy.

I hope this applies similarly to your build, and I hope this helps.

-Herbie

 

[Loopie]

That's a great tip/link Herbie! I hadn't noticed that thread before.

 

[kntr]

Im just curious. Maybe Im missing something here, but why did you do this? What was wrong with just the AWD. My AWD does great on and off road.

Why?

 

[Herbie]

Im just curious. Maybe Im missing something here, but why did you do this? What was wrong with just the AWD. My AWD does great on and off road.

Why?

I can't answer for Zuren, but my main reason for heading down this path: Low Range - my van isn't the all-conquering offroad racer, so being able to crawl over tricky terrain saves a lot of other problems. Without the low range, I just don't have enough control over speed over trickier stuff without riding the brake...

 

[zuren]

I can't answer for Zuren, but my main reason for heading down this path: Low Range - my van isn't the all-conquering offroad racer, so being able to crawl over tricky terrain saves a lot of other problems. Without the low range, I just don't have enough control over speed over trickier stuff without riding the brake...

Like Herbie said, the #1 advantage is the low range. I do not have plans to take this van places that many here go but having 4LO will be extra insurance. I will also be pulling a boat in the next year or 2 and being able to lock into 4WD is nice when on slippery boat ramps. I gathered a couple fuel mileage data points before the conversion vs. after and for the driving I do, there seems to be no difference (what I mostly expected) so you neither gain nor lose in that category.

To me, 4WD vs. AWD are 2 different tools for 2 different jobs. On pavement, AWD is regarded as being better. My daily driver is an AWD VW station wagon and I love it but if you ignore wheel base and clearance, I would think 3 times about going down a questionable road/2-track (after doing it a couple times); I have been stuck or came close. 4WD systems are regarded as being better offroad but worse on pavement than AWD. Here are a couple articles that are probably a good deal of opinion but they speak to the matter better than I could:

Article 1

Article 2

If you search for "4WD vs. AWD" in Google, you'll find quite a bit of info. Overall, I wanted a part-time 4WD van and this was the most economical way I found to reach that goal.

 

[haven]

If you're looking for an Express AWD van, visit sites like
www.truckpaper.com and www.commercialtrucktrader.com
I found several for sale on each site this morning.

Most of the ads I saw had prices around $15K.
Here's the cheapest I found:
http://www.commercialtrucktrader.com/find/listing/2005-CHEVROLET-EXPRESS-1500-97744041

2005 Chevrolet Express 1500 AWD
158K miles, $9000
5.3L V8, auto trans
panel van, swing out side doors

 

[tinbasher]

have you tried putting the shifter in 2nd? every 4l60e i've driven if the shifter is in 2nd it starts in 2nd. it might give you an extra gear in low range.

 

[zuren]

have you tried putting the shifter in 2nd? every 4l60e i've driven if the shifter is in 2nd it starts in 2nd. it might give you an extra gear in low range.

That may buy me a little bit of speed. I'll have some time tonight to look into Herbie's idea about the PCM and the same issue with the Astros. The friend that helped me said that Chevy/GM is famous for reusing the same technology across different models and years.

I'm assuming a GM "PCM" (powertrain control module) is the same as the generically termed "ECU" (electronic control unit) that other car companies use?

 

[zuren]

Zuren, regarding your transmission-shifting-while-in-4LO issue:

Check out this thread on the AstroSafariVans site:
http://astrosafarivans.org/bb2/viewtopic.php?f=21&t=1940&hilit=switched+power

Read the whole thread for all the details, but the summary is this: On the Blazer and Astro/Safari TCUs, there's a pin that tells the TCU when 4LO is engaged that allows the shifting to work correctly. On the Astro/Safari TCUs, this pin is not connected BUT IS APPARENTLY FUNCTIONAL if you add a pin to the connector.

The OP on that thread solved the problem with a manual switch to ground the pin, but after more research, I believe that some of the NP transfer cases included a switch or sensor that closed (to ground) when 4LO is engaged, making it automatic. Even if your transfer case doesn't include the provisions for this switch, rigging up a microswitch that gets triggered by either by your shift handle or the shifting lever on the transfer case body should be fairly easy.

I hope this applies similarly to your build, and I hope this helps.

-Herbie

Thanks for this info Herbie! If Chevy holds true to many things being similar between models, I hope there are similarities to the Astro/S10 PCM and the Express PCM. According to Chiltons, my PCM is located in the driver-side engine bay, behind the washer fluid reservoir.

 

[howard101]

Has anyone here rented a handicap van before? I would really like to rental one. Would they be giving out special deals for the holiday time, a lot of people are going on vacations that time of year. If anyone can help that would be great, cheers!

 

[endneu913]

Bull bar is also on the list but as you know, there is nothing off-the-shelf available. I'll be interested to see what you come up with.

Awesome write up!!

.... Thought I would drop in on the conversation and add my findings. AWD vans are out there, but patience is a virtue! It took me 3 months of searching for the right one, which would have been cargo, black, leather and a CD player, but ended up with the more common base model cargo AWD, cloth and am/fm. ( 2005) Which I finally found on good old craigslist in my city, for a steal- $5k

A month or so later I found an amazing deal on an aftermarket Silverado 1500 / 2500 bumper/ brush guard combo ( again craigslist) for $200 bucks! With a small amount of modification, and I do mean small ( i don't even own a welder ) I was able to bolt this cow killer up in a matter of a few hours and my own sometimes "stupid" determination. ( I love it when friends tell me "it wont fit" ) Add on some black and steelies and A/T tires and were ready to hunt some Zombies!

The major effort was just lifting the darn thing ! I did have to make some cuts to the upper deck of the bumber portion, and drill some holes in the chassy for extra structural integrity, but overall it works amazingly.The only fitment flaws are the side/ ends of the diamond plate on the bumper dont follow the body lines "perfectly" but are passable and changing out the turn signal bulbs is less easy then before... :ylsmoke:

Im happy to share specific details and build photos with anyone that wants to attempt such nonsense, i fully endorse it!

As you can see, the winch bed will be a breeze for me with the 2" receiver on the bumper, but DAMN that welded in winch bed disguised under the stock bumper is slick! I fully agree with the logic on that.

Oh Also, there is ONE aftermarket bolt on that ive found, for sale here, by "go-Rhino"

http://www.autoanything.com/grille-guards/61A2423A0A0A2353437.aspx

and can be viewed on a van here:

http://www.gmtruckclub.com/forum/showthread.php?48499-Go-Rhino-brush-guard

Keep Exploring!

- Grae ( new, obviously )

 

[Accrete]

congrats on the front bumper find&install, it looks GREAT!

I wanted to send an update on my flexiflare install as you were asking on the other thread. The sides of the van look nearly as fresh as the day-after-flare-install wash i did...and it has been two weeks of driving on wet muddy oregon coast roads. I think you would be pleased with them on your van.

cheers,
thom

 

[zuren]

Hi endneu913 -

Thanks for posting! I would be interested in seeing how bumper mounted up in this thread or I would fully encourage you to show off your rig in a new thread and post the link here. I'm thinking something a bit simpler like a bull bar but the mounting underneath should be similar to your solution. Something like this:

There are light bars and "baja bars" out there but they don't appear to be stout enough for multiple purposes like a bull bar.

Thanks!

 

[Accrete]

...There are light bars and "baja bars" out there but they don't appear to be stout enough for multiple purposes like a bull bar.

I'm leaning this same way as we want to keep things light on the 1500, i will try to keep in touch with your build zuren and see how it goes.
cheers,
thom

 

[JMyerz]

Oh man! Of course you had to post this just when I've been considering selling mine! Good job on all the research. I'm curious though, did you explore the route of push button 4WD from a later model truck? I'm wondering if it would work or not.