[caveysclubs]

I am planing to build a 4x4 conversion can for mild trail rideing. I want to use the van for road trips out west from Ohio. In order to afford gas I want to get the best has mileage so I was wondering if anyone knows of a s10 hub assembly with manual lockout will work on the Astros frame.

 

[Rod's Trucks]

I am not knocking the idea of locking hubs. They definitely have their advantages.
But I suspect unless you are also changing to a full manual transfer case, you will not gain anything worthwhile as far as fuel economy, for your efforts. The front drive components will probably still be turning, even with hubs are unlocked. The transfer case will not know the difference, unless it is converted to a full manual case, with a neutral position.

1000 miles at 16 mpg ( being optimistic ) uses about 62 gallons of fuel.
If you managed to increase fuel economy but a whole 1MPG ( highly unlikely) ; then 1000 miles at 17 mpg would use nearly 59 gallons. ( a possible three gallon savings)
If you were increasing from 14mpg to 15 mpg, the numbers are a bit better ( bigger % increase in gain). ( about 71 gallons vs. 67 gallons)
So you 'might' save four gallons over the trip if your economy increased by a whole 1 mpg.
But you are going for mild trail riding, so probably somewhat 'lumpy' tires. That also would hurt fuel economy to some extent.
Also, beware most ( if not all) S-10 wheels have a different bolt circle. I do not remember ( have not played with one in nearly 40 years) if locking hub assemblies are different for different bolt patterns, but I suspect they would be. I cannot recall what pieces needed to be changed to go to the WARN manual hubs.
Rod J
Issaquah, WA

 

[markmitch]

S-10 is 5 x4.5 whereas the Astro is 5 x5 bolt patterns are different. The only thing different from the front axle on the Astro to the S-10 is the lockout itself. Which as Rod said only frees the wheels in the sense that the hubs are not powered but freewheeling when locked out. The transfer is still sending power to the front axle, just not the front hubs. Very little if any gas mileage saved. People don't buy Astro/Safari vans for gas mileage, they buy them because they are great vans overall.

 

[Mmusicman]

Cool... Rod did the math.

Seems the few gallons saved on even a long trip may not be even close to being worth the added expense, complexity, and labor. But I admit I've considered it too... but have since decided I'm not going to bother.

Another consideration regarding the AWD unit (if you intend to use it)... is that it has clutch preload. This means it DOES spin EVEN when not engaged. This is why it is important to have 4 matching tires while driving.. all on the ground and turning the same speed (hence the damaged caused by improper towing). Note the front tires STILL drive the system backwards (when not engaged), but it's all turning regardless.

The front shaft MUST spin at same rate as rear shaft.

Eliminate the front tires from turning the unit, and I wonder if the pre-load will STILL turn the output, or sufficiently enough to match so as not to burn up the clutch-packs. If you plan to utilize a true manual 4x4 transfer case.. then this part of the discussion no longer applies.

As mentioned.. aggressive tires are the real killer of MPG. I do 99.99% of my driving on road or the highway, and can count on my hand the number of times I've actually pulled it into 4WD for quick use... or needed this type tire. I also realize everyone's situation may be different. LT tires are a must... but I've also gone with an HT (highway touring) tire designed for lower rolling resistance which increased my fuel economy quite noticeably. Nice and smooth too. But yet I still have excellent 4x4 use, and it's an extremely rugged commercial 10 ply load range E tire that does well off-road too.

Just some more food for thought if you're looking for efficient fuel economy..

 

[floyd.gene]

I read somewhere and trying to find it again that Suburban locking hubs work on the Astro. Looking for a set myself so I can unlock the front hubs when I've got it in 2 high or can even run it in 2 low for heavy towing