Make a 4x4 a 4x2

My wife has to drive her Rodeo from NH to Florida. I'm looking to improve the mileage for the trip, is it possible to temporarily disconnect the front powertrain? Something to remove from the front auto hubs so the axles and front diff gears aren't connected?

You can install manual hubs, but that may only give you an extra 0.2 mpg.

The best way to get better MPG, is a clean air filter, increase your tire pressure by a couple of lbs. and don't go over 65 mph.

Correct me if I'm wrong (which is entirely possible), but with auto hubs doesn't the front drive shaft, diff gears, and front axles turn when the front wheels turn, even when in 2WD?
If so wouldn't the MPG gains be much higher with the resistance of these removed?

I think the only thing you could stop from moving would be the front drive shaft maybe but that would involve taking out the diff gears because the axles would turn anyways. As long as the transfer case isnt engaged theres not really much you can do.

Your front drive shaft (on all 1998+) does not spin in 4x2 mode due to the open front diff. It doenst move, just free-wheels. Like Amigo2K says, you can install aftermarket manual hubs on pre 2002 rodeos to keep the front axle from spinning in 4x2, but you wont see any major MPG increase. Keep the tire pressures to spec & try to keep your speed down to maximize hywy MPG's. Anything over 65MPH yeilds some pretty crappy gas milage in these trucks. Make sure to check your oil level at every fill-up during long hywy trips!!
G/luck
Joel

I run my tires at 32psi the spec 26psi is far too soft and kills your mpg. At 32psi I average at least 21mpg mostly highway with stop and go trafic, at 26psi I was getting about 18mpg.

Couldn't agree more with all the suggestions; with the exception that I have the older model, and my spec psi is 29 frnt/32 rear. Agree, I find that's too soft, and makes for not-so-good mileage along with not as good giddy-up on the highway.

I run 36 psi frnt/rear, unless I have a good load in the back. Makes for really good mileage, generally 18mpg city/21-23 open highway. For an older Rodeo with 123K, that's pretty darn good.

Definitely keep at no more then 70mph on the highway, and can't stress enough to check the oil constantly.

Thanks for the info guys, I run the tires at 36 psi now because anything less is too soft, guess I'll just leave it as is, I might change the hubs to manual, that should at least save wear on the CV's wouldn't it?

Be careful when "adjusting" the tire pressure above/below what is specified by the manufacturer. In my opinion, 36psig is WAY too high for a 2000 with stock sized tires for on road use. If isuzu knew they could safely squeeze 0.5mpg more out of a rodeo by boosting tire pressure alone, they would have done it long ago!! Door jamb tire pressure spec's are designed 1) For safety, handing, roll-over resistance, 2) Economy, 3) Ride comfort. I know my 2002 LS 4x4 has scarry handling characteristics with tire pressures at or above 30psig, even with better shocks! Protect your own & others on the road by dropping the pressure a bit .

G/luck
Joel

For stock sized tires on a 2000+, yes, 36psi is a bit high for you newer guys. If I didn't point it out before, I may have forgot to say that I have the older model with LT245/75 16's versus the P225/75 16's it came with.

I actually find that taking my psi back down to 29 frnt/32 rear, I have less handling ability and heck of a lot more lean in turns - actually like the tire is rolling off the rim when cornering. And quick lane changes lead to rocking a bit, even with brand-new shocks. Put em at 36psi, for a 97 Rodeo, and all rocking/swaying stops.

I'll never go back to OEM specs for tires or psi, them skinny little tires added to the swaying personally.