Best way to switch from full time 4x4 to part time 4x4

[Robert Frederick]

I am looking to purchase a 1979 Dodge Adventurer 150 that is a 318 2bbl automatic with the full time 4x4. I plan to make this my back and forth to work vehicle (21 miles one way). I want to improve fuel mileage by swapping out the trans and transfer case so this can be a part time 4x4 with overdrive. Did they ever install this set-up in carbureted trucks in the late 80's? Any other suggestions? I would like to keep the 2bbl 318 as it is a rebuilt engine.

Thanks,
Rob

[712edf]

Not sure when overdrive appeared in 4x4 trucks, carbs dissappeared around 87 or 88....88-90 had oddball hall effect distributor also.

I take it the 318 is in the 79 that you're looking at.

The 75-80 full timers have a bad rap for mileage/parts wear but honestly things didn't improve much until the magnum motors showed up in early 90's. If you already owned the 318 I'd say stick it in an late 80's truck that had the O.D. already in it.

Unless you have access to a cheap (free) 518/208 combo and all the little pieces that may be needed for the swap, this may be a costly swap in terms of what it benefits you.

Cheapest route would be find a newer truck instead. I guess a donor truck is reasonable but I don't think the small mileage improvement will justify the effort.

Having said that, I prefer the 70's look over the 80's trucks though.

[DODGEBOYS]

you would need from the ball joints outward from a 1981 to 93 truck or RC [ that includes - knuckle-spud shaft-spindle-rotor and caliper with hose]

on the tranny you would need a 1988 to 91 truck or RC with the OD button below the headlight switch / if it does not have the OD button on the dash its not the tranny your looking for

[Robert Frederick]

Wow, why would I need the different knuckle and such? How are they different. It's sounding like a donor truck from '88 to '91 would be ideal. Now I know the 318 switched to the Magnum version in '92 but the 360 switched in '93. Could I get away with a '92 truck if it had the 360?

Rob

[opqual]

yeah, my 75 w100 won't be a daily driver, but I assume that when it snows, this thing will go anywhere...

[712edf]

Wow, why would I need the different knuckle and such? How are they different. It's sounding like a donor truck from '88 to '91 would be ideal. Now I know the 318 switched to the Magnum version in '92 but the 360 switched in '93. Could I get away with a '92 truck if it had the 360?

Rob

The 75-80 axle (yours) has no provision to disconnect the wheels from the drive shaft, so if you switch t-cases everything would still rotate anyways. Only all the front drivetrain would be "driven" from the ground not the engine.

A complete axle swap would also work but those later axles have a CAD (central axle disconnect) which is deemed weaker than yours.

Why do you desire a 360 donor truck?

[Robert Frederick]

It's not that I want a 360 donor truck...I was just listing potential donors...I am guessing that would be the best way to accomplish the fuel economy improvement...but I'm really looking to the experts on this list for the best way...what would you recommend?

Rob

[712edf]

Go with Dodgeboys plan of 88-91 truck/ramcharger for the od transmission, t-case and possibly the drive shafts.....In my opinion 318's get a tad better mileage than 360's but not enough to totally rule out one or the other.

My 79 318 4-speed W200 club cab only got about 9 mpg & wouldn't run over 55, just geared too low (6.69 first, 8.25 reverse, 4.10 final).

My 95 Ram 1500 360 magnum with OD auto got 14 mph local, maybe 18 highway and truly was possibly the best vehicle out of 30+ that I have ever owned. But later model (post 93) Rams are a different animal drivetrain wise after the flywheel.

Something else to consider is throwing on some taller tires. These trucks should fit something up to 33" in stock form. You don't necessarily have to go wider, just taller. Lighter wheels are a benefit too, but costly.

[OLD DODGE]

Or.....

Leave it stock and enjoy it the way that it is.

[Robert Frederick]

The more efficient I can make it...the more I can enjoy it. As in every day! I can't leave anything alone...I always have to improve it in some way. At least from my point of view.

[mopar65pa]

Leave it stock and enjoy it the way that it is.

I'm with this.

I've had full time 4x4 trucks get anywhere from 12 -18 MPG (318-2 bar) Yes parts wear out on them BUT not any more so that the new ones. The full time front 44 hubs need greasing more often than the 81-93 CAD 44.

I have an 80 Trailduster that is part time with a 318-2bar, 4 speed that only got 16 on the highway.

IIRC The newer trucks 94+ IFS have the front running gear spinning all the time too. It's just the transfer case is "free" to the front shaft until you lock it in.

Personally I think full-time 4x4 got a bad rap due to poor maintenance.

Taller narrow tires, grease the whole front end, a good tune up, and mid grade gas will do wonders to improve mpg

[712edf]

I have an 80 Trailduster that is part time with a 318-2bar, 4 speed that only got 16 on the highway.

Same mileage as my 2004 Astro van. Full sized gasoline powered trucks generally get mileage in the teens. Alot of folks here would be happy with 16 mpg from a lifestyle era truck.

[opqual]

After a week of driving, and and a fill up each day of approx 6 gallons,,,

I achieve 10mpg... LOL

I too, think stock is the way to go. Unless you can modify inexpensively, it,s not worth the cost.

I would think it would be better to weigh the options when something breaks.

I thank you again for notifying me on the zirks in the front wheel hubs! I never would have found them myself...

Still not sure how much to pump in there though??? I pumped 10 times in each hole without seeing any grease oozing from anywhere. I didn,t want to go overboard.

[mopar65pa]

After a week of driving, and and a fill up each day

Still not sure how much to pump in there though??? I pumped 10 times in each hole without seeing any grease oozing from anywhere. I didn,t want to go overboard.

Keep pumping it won't hurt to have too much.

Really you should drive it maybe 4 days a week and re-grease them if you don't know when they were greased the last time.

I have a buddy that has 200K miles on his front hub bearings in a full-time and they are just now to the point now that they should be replaced.

Good luck.

[smalltowncowboy]

A couple people have said go with a bigger tire, but that depends on how your geared and what size tire you have already. My axles are geared at 3.04 (for now), so a taller tire wouldn't really help my mileage.

My ideal swap would be a cummins 12V, and a dana 60 out of a 80's chevy. Lol but then again I can't leave anything stock, look at my 80 powerwagon.