1997 awd chevrolet astro van


I recently bought a used 1997 chevy astro van and when I took it to the shop to gt its fluids changed and some new tires installed. I manged to arouse the curiosity of every person in the shop. It seems my vehicle has been outfitted with multiple devices which no mechanic has ever seen before. They postulated that the vehicle has a system for running on natural gas as well as a strange after market air charged system which is attached to the rear differential and wheels. It is far to complicated to be a air locker for the differential. I would happily submit pictures or come on the show and chat about the problem as the local experts have never seen anything like this before.

Can you post pictures here?

Howdy, My apologies for taking so long but I just want to sell the thing and get something simpler and more stragiht forward for a car camper. There are jsut to many aftermarket parts and extra enginerring involved in this thing.

I hope you can chat better than you photograph, the photos are useless.

Yep, There is so much custom work that the pictures can’t do it justice. Pic 1 is possibly the pressure regulator system. Pic 2 is under hood and we guessed that was where the gas went in. Pic three is the 26,000 psi pump for something… T The line continues from that pump to a manual cut off switch with a WARN “w” logo on it, and then onto each rear drum and the center diff. I should add that if there is some sort of air locker system. I could find no bleed valve atop the differntial which makes me think that the Borg warner traction system from that time period may be integrated into this mess somehow… I’ll get it on a rack this week and post more pic’s. It continues to be a mystery to me too and apologies for wasting your time. It is very difficult to figure out what all this stuff might be.

When taking the pics, see if you can get a better angle on the labels and name plates such as the one in pic 3. There must be more on the other apparati as well.
If pics arent possible , write down the info like brand names and numbers.

With all this oddball stuff on there you’d really like to know how to use it before it becomes a money pit.
Did the previous owner furnish any user manuals for this stuff ? ( apparently not or you wouldn’t be asking us for help. )

I think I can help a little bit. The cap in the second picture is labeled “CNG Only”; CNG stands for Compressed Natural Gas. I know that you can get vehicles retrofitted with CNG fuel systems for the engine, but I don’t have the first clue how something like this applies to the differential or whatever it’s attached to.

Thanks for the reply and we found the place where a small tank may have been attached. People surmise that it was a cng assist vehicle which means it still ran on fuel but had natural gas also to increase fuel performance at the cost of hp. I think the aftermarket differential can provide some model numbers and maybe I can get some clear images of the whole bottom of the truck for persepctive and further speculation. THanks for the input.