Astro/safari AWD Question

[fjatheart]

Hello All,

I'm researching the Astro's and Safari AWD vans. Are these vans equipped with a selectable 4wd or are these vans always in 4wd, similar to a later model 4runner or Land Cruiser? Do these vans have a low range option or is it strictly put it in drive? In stock form can one of these vans handle beach travel, sandy conditions?

Is it common for owners that use them off the pavement to convert these to a selectable t-case?

Is there a FAQ section for these vans?

Thanks,
Trae

 

[Railvan]

Paging T.Low...

They were built as AWD but a transfer case swap will get you low range:

http://astrosafarivans.org/bb2/viewtopic.php?f=21&t=2586&start=15

I'll let Tom and others fill in the details as they know more than I.

Brian

 

[ihatemybike]

The All Wheel Drive vans are basically full time four wheel drive. 1998 and earlier van use a viscous clutch, while the 1999 and later vans use speed sensors and an encoder motor to activate. These vans actually do really well off road with the stock set up.

This is Grumpy, completely stock on aired down Primewell passenger tires.

Grumpy handled quite well in the dunes at Badlands Offroad Park later in the day of the video.

Several two speed transfer cases have been swapped into these vans, but they are clocked differently. Most clearance the the crossmember to clear the driveshaft.

The biggest benefit to the two speed transfer case is handling long steep up and downhill. Really nice to have the gear reduction for the climbs and engine braking on the descents.

 

[Herbie]

Having just returned from the SoCal Desert Rendezvous, I can say with certainty that the stock electronic AWD transfer case in a 2003 van will handle deep silt, dirt roads, and washboards just fine. Aired down and just cruised. Only felt it feel like it was getting caught up a couple of times and just keeping the throttle neutral and momentum going carried the day.

That said, I will eventually swap to the NP231C because I want to be able to crawl slower over some of the obstacles.

 

[fjatheart]

All great information! I'm currently searching the classifieds, but wanted to make sure I know what I'm getting into.

Is the 231 as simple of a swap as the 233? Being that it's a manual case, what wiring mods have to be done to compensate for removing the stock AWD case? Has this been documented already as well?

Thanks again!

 

[Wiley]

Yup, these things perform well. I did two months in Mex and only got stuck once, and that was because I didnt have my compressor hooked up and wasn't aired down, it was an empty rv park on the beach at night so we thought we were good, I even had my friend get out and test it, seemed ok, but the weight of the AWD sink us in. We waited till the next morning to push it out with help from 2 guys, it came out easy. Full inflated though and the tires didnt want to move...no spinning, no nothing. I dont know how the AWD works but it was kind of strange.

 

[ihatemybike]

Transfer case swaps have been documented on two forums, www.astrosafari.com and www.astrosafarivans.com. No wiring mods need to be done for manual cases, pulling the AWD fuse on the later vans will deactivate the system.

 

[Basement Yeti]

If memory serves me correct ihatemybike an I discussed swapping in a transfer case that would allow AWD and a low range as well. Maybe. I forget.

-Kyle

 

[ihatemybike]

There are a couple transfer cases that have 4FT (also know as AWD).

NP242 uses a center differential, giving 2HI, 4FT, 4PT, N and 4LO.

NP249 uses a viscous clutch, giving 4FT, N and 4LO.
The viscous clutch in these get a bad reputation, due to people not shifting into 4LO when they should and overheating it.

NP236/246 use front and rear speed sensors and computer to activate a clutch pack, giving 2HI, 4FT, 4PT, N and 4LO.
It may be possible to use these in the 1999 and later vans.

 

[fjatheart]

You guys are great. Thank you for the information and links. Now if I can just find an AWD in my area.

Thank you,
Trae

 

[T.Low]

Hello All,

I'm researching the Astro's and Safari AWD vans. Are these vans equipped with a selectable 4wd or are these vans always in 4wd, similar to a later model 4runner or Land Cruiser? Do these vans have a low range option or is it strictly put it in drive? In stock form can one of these vans handle beach travel, sandy conditions?

Is it common for owners that use them off the pavement to convert these to a selectable t-case?

Is there a FAQ section for these vans?

Thanks,
Trae

As already stated, no they don't come with selectable 4wd; they are either a 2wd model or an AWD model.

No low range in stock form.

It is not uncommon for them to be converted to a selectable Tcase.

My first trip in my van included a stretch of about 15 miles or so down the beach. At that time I had not yet done the tcase swap and got a little worried at times while off the hard pack. It definitely bogged more than I was comfortable with. I did not get stuck, but again, was not confortable with the rpm bog level.

ALso, I like the slow and easy method like Herbie refers to, being able to crawl over the rough stuff, as well as keep the revs high in beach sand.

http://i232.photobucket.com/albums/ee258/wannahuckmastinky/Astro Mini Me SMB build/IMG_1746.jpg

 

[Herbie]

No wiring mods need to be done for manual cases, pulling the AWD fuse on the later vans will deactivate the system.

Aaron can correct me if I'm remembering wrong, but I think there's a 1-wire change needed even with the manual t-case on the newer vans. Those with speed sensors, etc. get tripped up when they see the input/output speeds change when in 4Lo, and won't come out of 1st or 2nd gear, I think. The change is to ground a certain pin on the ECU (not populated on the Astro, I believe) when in 4Lo. This should be doable either with a microswitch on the transfercase or selector mechanism or with a manual switch you can throw. It's covered in the "Transfercase Swaps" section on AstroSafarivans.org

 

[fjatheart]

As already stated, no they don't come with selectable 4wd; they are either a 2wd model or an AWD model.

No low range in stock form.

It is not uncommon for them to be converted to a selectable Tcase.

T. Low did you lift and increase the size of your tires before you installed the NP233c? If so, did the larger tires make it even tougher to travel through the sand before the swap?
My first trip in my van included a stretch of about 15 miles or so down the beach. At that time I had not yet done the tcase swap and got a little worried at times while off the hard pack. It definitely bogged more than I was comfortable with. I did not get stuck, but again, was not confortable with the rpm bog level.

ALso, I like the slow and easy method like Herbie refers to, being able to crawl over the rough stuff, as well as keep the revs high in beach sand.

T.Low-

Did you happen to increase the size of your tires prior to changing the t-case? Was it even worse in the sand with bigger tires and the factory AWD set up?

 

[fjatheart]

Aaron can correct me if I'm remembering wrong, but I think there's a 1-wire change needed even with the manual t-case on the newer vans. Those with speed sensors, etc. get tripped up when they see the input/output speeds change when in 4Lo, and won't come out of 1st or 2nd gear, I think. The change is to ground a certain pin on the ECU (not populated on the Astro, I believe) when in 4Lo. This should be doable either with a microswitch on the transfercase or selector mechanism or with a manual switch you can throw. It's covered in the "Transfercase Swaps" section on AstroSafarivans.org

Thanks Herbie. It's nice to know others have been there and done that. I'm heading over to check out astrosafari.org shortly.

 

[Herbie]

Did you happen to increase the size of your tires prior to changing the t-case? Was it even worse in the sand with bigger tires and the factory AWD set up?

If T.Low didn't, I did. I'm still running AWD and I have ~30" tires now. I was very aired down when I was in loose silt, but if there was any bogging, it's only because I was in really deep stuff (like past the hubs). FWIW, overall tire diameter won't affect the transfer case performance that much (as long as diameters are the same). You'll experience a change in effective GEARING, which will make things feel different, but the transfer case is merely doing its best to keep the front and rear driveshafts spinning at the same speed.