Part time 4WD

[MOAK]

I’ve wanted to get rid of full time all wheel drive on my 450/80series for nearly a decade. A very good friend and I finished up the job yesterday, removing the viscous coupler ( a very nice boat anchor) and replacing it with a spool, and installing new birfields along with manual lock out hubs. The difference in drivability is amazing. If it’s true that I should get even 1.5 more MPG than before, the kit will pay for itself on our first trip beginning this Saturday. The truck is finally right where I want it. Suspension, bumpers, sliders, LR auxiliary fuel tank, part time 4wd. Done !

 

[1stDeuce]

It's been a while since this was posted, curious if you have checked to see what kind of actual mileage improvement you might be seeing... I actually put an XJ Cherokee transfer case in my TJ to get a full time mode. Center diff is open, not viscous, but I run it in full time mode most of the time. Noticed no mileage penalty, but in the TJ, all of the front driveline spins regardless of being in 2wd or 4wd...

 

[MOAK]

It’s hard to tell, in spite of over 6,000 miles traveled in the past month. The quality of gasoline differs immensely. Ethanol gas equals poor mpgs. Gas available on the Dempster is even poorer. Over all? Previous trips we average 11. We are averaging 11-12 mpgs on this tour. So maybe 1/2 more mpg. I’ve had one 500 mile stretch where we got 14mpg, the best I’ve ever gotten. Then again, up on the Dempster no more than 8mpg. Once home I’ll be able to measure using the same gasoline on the same roads, but so far, I’d safely say 1/4 to 1/2 mile more per gallon. That doesn’t seem like much, but on this trip 1/2 more will pay for the parts.

 

[calicamper]

Always w

I’ve wanted to get rid of full time all wheel drive on my 450/80series for nearly a decade. A very good friend and I finished up the job yesterday, removing the viscous coupler ( a very nice boat anchor) View attachment 784562and replacing it with a spool, and installing new birfields along with manual lock out hubs. The difference in drivability is amazing. If it’s true that I should get even 1.5 more MPG than before, the kit will pay for itself on our first trip beginning this Saturday. The truck is finally right where I want it. Suspension, bumpers, sliders, LR auxiliary fuel tank, part time 4wd. Done !
View attachment 784563

Always wondered how big of a drivability effect it had on my 80. No doubt a big suck on the mileage

 

[MOAK]

Abs

I've had a few full time Jeeps with QuadraTrac. The first a 1978 Gladiator with a 401.... no idea what the gas mileage was but it was expensive to run and I sold it. Then a 5.9 Grand,,, wonderful vehicle but the transmission eventually died and the $3500 bill made me say never again. I'm committed to clutches and part time 4WD now.

On the gas mileage vs 2WD vs 4WD.... My YJ did many 950 mile commutes Edmonton to Yellowknife. 2WD/4WD made no difference to the gas mileage. Some winter trips thru storms were 4WD from Edmonton to Yellowknife, most were 2WD but there was never an "oh wow 2WD gets better gas mileage". I stopped for gas in the same places and the fill was always the same.

I love the reliability of old fashioned mechanical shifting systems way more than some rotary switch on the dash. In the 1970s, I had a rear driveshaft explode... on a 1963 Chev 4x4.... pull the driveshaft and shift into 4WD,,,, now FrontWD and keep going. It took 5 minutes to get going again. Drop off the driveshaft for a rebuild and bolt it in a week later. I am definitely a fan of old school.

EDIT
Also a fan of buy whatever is popular, common where you overland. I've seen many cool but "odd" vehicles stranded waiting for parts cuz they "shipped" their vehicle overseas..... If you go halfway around the world make half the adventure shopping local for the most common wheeler they have and make the build part of the adventure.... even better if you learn a new language in the process.

Absolutely agree. Even though mine is an automatic, which I’ve gotten used to, there isn’t a known failure of the A343F under normal use. Ya, guys have blown them up because they lacked mechanical sympathy and beat them, but under normal finesse style driving? No failures. As far as common stuff? Ya, I prefer 255/85/16s, but good luck finding a tire shop in Fairbanks, Whitehorse or Dawson that can get them, so I run a common 285 tire size. My buddy got a bad puncture on the Denali highway, he runs an odd size- 12.50x35x16 had to buy a 315.

 

[brunjc2]

It’s hard to tell, in spite of over 6,000 miles traveled in the past month. The quality of gasoline differs immensely. Ethanol gas equals poor mpgs. Gas available on the Dempster is even poorer. Over all? Previous trips we average 11. We are averaging 11-12 mpgs on this tour. So maybe 1/2 more mpg. I’ve had one 500 mile stretch where we got 14mpg, the best I’ve ever gotten. Then again, up on the Dempster no more than 8mpg. Once home I’ll be able to measure using the same gasoline on the same roads, but so far, I’d safely say 1/4 to 1/2 mile more per gallon. That doesn’t seem like much, but on this trip 1/2 more will pay for the parts.

Any more reflection on this modification? I’ve spent enough time considering and need to make my mind up. I’ll be in the transfer case for the 3.1 low range gears soon enough, and I only want to open up the case once…

 

[MOAK]

Any more reflection on this modification? I’ve spent enough time considering and need to make my mind up. I’ll be in the transfer case for the 3.1 low range gears soon enough, and I only want to open up the case once…

Positives: the truck handles much better, no more understeer when cornering at highway speeds. We no longer listen to the front diff being noisy. By modest calculations roughly 1/4 gallon better MPG. Negatives: with the kit I used the 80 no longer has ABS, not a negative in my mind. Also, I know some folks have been spoiled with all wheel drive and would prefer it. However, I grew up around 2wd farm trucks and currently have a 2wd pickup as a daily. A lot of people would be off in the ditch with any adverse weather conditions in a light pickup with 2wd. So yup, you gotta drive the 80. To sum it all up? I should have done this modification years ago.

 

[2025 deleted member]

Does it seem to wander less? I assume steering is a bit lighter. Front tire wear should be better.