I'm curious if anyone has swapped hubs from lockouts(slugs, automatic hubs, etc) to manual hubs and noticed an increase in gas milage.

The reason I ask is because I "constantly" see people wanting to swap from lockouts to manual hubs and the most used reason is "I want better gas milage".

Is the logic a crock of shit or not?

Nothing I'm considering though I've given thought to going to a lockout on my FJ40.

I swapped a set of maul hubs into my truck hoping for more mileage. I do tons of local driving, very little freeway, some highway and I ended up with less than 1 mpg difference. I went through two tanks of gas before and 2 after to check it and it was something like 1/4 to 1/2 mpg better is all. I run em locked in the winter so I can throw the transfer case into 4hi on the fly when I need it and I don't notice any significant difference there other than the front shaft shakes a little over 70. Later

the logic is not a crock, but the better reason for manual hubs is less wear on the front and KNOWING the hubs are unlocked.

Originally posted by RHINO
the logic is not a crock, but the better reason for manual hubs is less wear on the front and KNOWING the hubs are unlocked.

Hmmm... that is interesting. What in the front end would(should) I be worried about getting extra wear? I wouldn't be overly concerned about the 3rd member getting extra wear since it would be under load. The only other area of concern would be a fubar front driveshaft(aka vibration)

Also, you said "KNOWING the hubs are unlocked". Can you honestly say you go and check your hubs everytime you drive your rig?:confused: Is "KNOWING" their unlocked a big deal? I'd actually be concerned with knowing they are locked :p

Not flaming or ragging on you just honestly curious.

what i meant about wear was when the front is locked, like w/o hubs at all just drive plates or whatever, the front is spinning at whatever speed you drive, it doesnt matter weather power is applied or not, its all spinning, from the shafts to the front of the case but mainly u-joint wear i guess. with manual hubs unlocked, nothing spins, or at least nothing is supposed to. now this stuff spinning isnt a concern for driveability, all wheel drive rigs drive nice, but why bother spinning and wearing the parts your not using?

as far knowing the hubs are unlocked, well auto hubs dont always work like theyre supposed to, especially with age, but when i unlock a manual hub leaving the trail, yes i know its unlocked.

this is all small beans, but another good reason for manual hubs is the breakage factor, what i mean is, you break something on the trail, you can pull all the related parts out on the trail to drive home, or if you have hubs, you can simply unlock to get out and pull stuff at home, again small beans but a plus non the less.

oh one other thing and its probly small i dont know, but when the front is not under power and its spinning from the tires turning arent the back (weak) side of the gears getting the friction?

I'm thinking drive flanges and lockers aren't the best option on the street. I'll keep my manual lockouts.

Rhino, thanks for the intelligent conversation. Your info makes perfect sence:)

On your last post(about "wrong" side of the ring gear), wouldn't that depend upon whether you have a high pinion or not. If it was a "regular" low pinion, the wear would be on the "correct" side of the ring gear:p

well i was thinking that the ring gear would be pushing the pinion instead of the other way, i dont know.

I think the fact its not under load makes a big difference. Theres no (or very little) pressure between the gear teeth and other moving parts that the thicker oil cushion between stuff would reduce wear to almost nothing.