Forum Discussion

msiminoff's avatar
msiminoff
Explorer II
Nov 16, 2017

New Gears and Lockers

Ever since upgrading to 19.5" wheels (10 years ago) I have felt that I was geared way too tall with the camper on-board, especially in the mountains and at altitude. In addition the inability to air-down has left me with limited traction and on several occasions caused me to get stuck on soft surfaces and sand.

I finally decided to remedy the situation by re-gearing from 3.73's to 4.10's and adding Air-Lockers front and rear. While I was at it I installed a new ARB compressor, a high capacity aluminum rear diff' cover, and I built a new mounting panel for the locker and air-bag switches.

Overall I couldn't be happier. The truck accelerates & shifts way better, and feels like it's in "just the right gear" all the time, especially climbing long grades. Prior to the gear swap I was concerned that I'd get a lot worse MPG unloaded, but I couldn't have been more wrong. I just did a 1000 mile trip to Death Valley and back (incl' 200+ miles off-road) and got nearly 2 MPG better fuel economy (hand calculated) on the highway than I have ever gotten in my truck before... and this was with a roof-tent on top. The improved economy is proof that the 3.73 gearing was too tall.

While I wasn't in any situations in Death Valley where I needed to use the lockers, I did play with engaging them a bit and the difference in traction compared to open diff's is nothing short of astonishing. Locked when you need it, open when you don't :C

I haven't had a chance to go for a spin with the TC on the truck yet, but I'm looking forward to a lot less downshifting, lower EGT's, and better MPG's. Will update here after the first TC outing.

Cheers,
-Mark




Truck Campers
  • av8rds's avatar
    av8rds
    Explorer
    Nov 16, 2017
    I've been thinking of adding ARBs for a few years now....its just such a huge $nut$ to crack! Its a great idea though!
  • Kayteg1's avatar
    Kayteg1
    Explorer II
    Nov 16, 2017
    I would love to have lockable differential, but it was only SRW option with Ford, so had to settle in LSD. Still great help when you are in desert dust.
    How did you calculate mpg? Did you recalculate odometer difference from real distance?
  • SidecarFlip's avatar
    SidecarFlip
    Explorer III
    Nov 16, 2017
    I've run an ARB air locker in the front pig of my 1997 F350 Ford Diesel sine 1998 with no issues what so ever but I run a Detroit Tru-Trak in the back pig. I engage the ARB using the air supplied by my on board compressor that supplies my air ride bags.

    Like I said, never had an issue. I don't want an air locker in the back, tire wear becomes an issue and the Detroit senses wheel slip and locks and unlocks by itself as conditions warrant.

    My only caution is, the pinion pre load must be set correctly by a competent shop and the ring must be checked for tooth engagement.

    It's a good unit (ARB and TT).
  • ScottG's avatar
    ScottG
    Nomad
    Nov 16, 2017
    Nice!
    I would like to have an air locker for the front but wouldn't get enough use out of it to justify.
  • cewillis's avatar
    cewillis
    Explorer
    Nov 16, 2017
    msiminoff wrote:
    Locked when you need it, open when you don't

    That's the key, alright. Good job.
    I wish there was an E-locker like I have in the front to replace the stock G80 auto-locker in the back.
  • time2roll's avatar
    time2roll
    Nomad
    Nov 16, 2017
    cewillis wrote:
    I wish there was an E-locker like I have in the front to replace the stock G80 auto-locker in the back.
    For the front I recommend Eaton TruTrac. Not quite a locker for rock crawling however it does transfer tons of torque and both wheels will spin together in mud, snow, sand and dirt. No steering issues and TruTrac is always in play and ready to go on or off pavement. I have these front and rear with no issues in 12 years.
  • SidecarFlip's avatar
    SidecarFlip
    Explorer III
    Nov 16, 2017
    Back when I bought mine in '98, they weren't bad. I think the ARB and install was a grand for the front and the Detroit was 800.

    I'm pretty good mechanically but when it comes to setting preload and coast and load on the ring gear, I leave that up to a good, reputable shop. Takes skill I don't have to set it correctly. Already had the 4:10 gears so no ring and pinion change was required.

    I kept my manual hubs in the front as well. No point in turning over the output shafts and universals when I don't require it so it's still lock the hubs in front.

    One thing to remember about a locked spool is it's fine going straight but you turn the wheel and the front end will bind unless you are in sand or dirt. Hard surfaces and a locker (especially with a loaded truck) can find the weak point in the driveline real fast, usually a universal joint but sometimes a drive hub or wheel output shaft.

    When I lock mine, I'm always going slow and always attentive as to the angle of the front wheels and. the truck won't want to turn any. It wants to go straight no matter what.

    Still carry my Lewis winch. Sometimes, locked diff's don't cut it.
  • cewillis's avatar
    cewillis
    Explorer
    Nov 16, 2017
    time2roll wrote:
    cewillis wrote:
    I wish there was an E-locker like I have in the front to replace the stock G80 auto-locker in the back.
    For the front I recommend Eaton TruTrac.

    I like the e-locker just fine.
  • time2roll's avatar
    time2roll
    Nomad
    Nov 16, 2017
    cewillis wrote:
    time2roll wrote:
    cewillis wrote:
    I wish there was an E-locker like I have in the front to replace the stock G80 auto-locker in the back.
    For the front I recommend Eaton TruTrac.

    I like the e-locker just fine.
    Yea I read the statement wrong ;) e-locker must work excellent.
    I can't imagine there is no selectable locker to replace a G80.

About Travel Trailer Group

44,029 PostsLatest Activity: Jan 20, 2025