New Gears and Lockers

[msiminoff]

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

[anthonyca]

msiminoff wrote:

2 MPG better ? VERY IMPRESSIVE !

Yeah, I'm totally blown away by this! I expected expected worse MPG unloaded and about the same (or a smudge better) with the TC on. It's a really nice bonus for sure.

ARB locker are kind of expensive, especially with the compressor. Did you look into E-lockers?

I looked at all of the available options before deciding on ARB. In second place was the combination of TruTrac in the rear and E-Locker up front. I already had onboard air and I wanted to have a bulletproof driveline that had excellent street manners (99.9% of my driving) and was a spool when I need it to be. I felt like I needed to re-gear, and at that point the brand of locking diff I selected really didn't change the total cost all that much.

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.

I also do all of my own wrenching, but I let the nice guys at Rearend Specialties install the gears for me. Their shop does one thing and they do it very well.
There's zero gear noise at all and when I pulled the cover off to do the fluid change the wear marks are full depth and dead-center on the ring gear.

No point in turning over the output shafts and universals when I don't require it...

I have manual hubs too, so none of the front drivetrain is spinning when it isn't needed.

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.

Can't imagine any time when I'd lock either diff' on a hard, dry surface. I'd say there's a pretty good chance that I'll never actually need to lock the front one off-road... it's just insurance.

Still carry my Lewis winch. Sometimes, locked diff's don't cut it.

Ya, I carry a MorePower puller for exactly that reason.

How did you calculate mpg? Did you recalculate odometer difference from real distance?

Um, I divided the number of miles driven by the amount of fuel I put into the tank... I've counted ever gallon of fuel I've put into the truck since the day I bought it.
Yes, my speedo has been re-calibratedand matches my GPS within ¼ MPH.

I don't want an air locker in the back, tire wear becomes an issue...

Tire wear? With an open diff?

Cheers,
-Mark

There is a shop I haven't heard of or thought of for years. They used to build the rear ends for all my friends cars.

[burningman]

Stop it, you’re making me want to go buy a Truetrac and ARB and my truck never leaves the pavement!

[SidecarFlip]

Couple comments from me and my experiences over the last decade and a half with the ARB and the Tru-Trak. Tire wear is the same on the back and front. Diesels are tire eaters anyway, lockers or open diff. Nature of the engine ant torque. I pay no attention to that.

My fuel mileage with my Ford has always been good so long as I keep my road speed below 68. Over 68, it goes south pretty quick, 4:10's are deep gears.

My truck does things other than tote a truck camper. It's a farm truck and it hauls around a tandem axle gooseneck that is usually very overloaded. I'm a typical farmer so the fewer trips made the better. I've loaded 20K plus of round bales on the trailer and went down the road before. You need deep gears for that kind of abuse.

I like the 4:10's off road in 4wd because my low range is so low you can walk faster but it has all kinds of power and I'm not in a hurry anyway. You get in a hurry off road, it usually turns into carnage time. Fools go fast, only fools.

I run a Lewis Winch because I always have a chainsaw with me along with other tools as well. You never know and the Lewis uses my Stihl Chainsaw powerhead. I think I've used it one time but I was glad I had it. It only takes one time.

Never an issue with the ARB. I had reservations about the air engagement/disrengagement but it's been trouble free and I use the 12 volt on board compressor that keeps my bags aired to actuate the ARB. The Detroit has been without issue as well. I did have an outboard seal issue with the corporate 10.25 rear axle but it was my own doing. I got mud in the vent hose and the differential couldn't vent so it vented the way of least resistance, an outboard seal. It was brake time anyway so I replaced both sets of rear shoes (my truck has drum brakes on the back, remember, it's a 1997 and 2 new outboard seals went in too. Easy-Peasy with a full floater. I re routed my vent line so hopefully it won't get mud in it again.

I've had no problems with either and the rear especially has gotten me though some stuff. I have a creek crossing to negotiate to get to my property in Northern Michigan and sometimes it can be, shall I say dicey, especially with the camper on.

I have toe stock diff covers, always did. The rear cover has no provision for draining the hypoid oil but I haven't an issue pulling the cover to drain it anyway. Gives me a chance to inspect the works.

I change my differential oil every 2 years (same with the E4OD fluid and filter, no matter how few miles I run. Oil is cheap. I get it in 5 gallon pails anyway. The exception to that is if I do submerge the wheels to the axles, then, when I get home, they get drained and refilled and the front outboard wheel bearings get cleaned and repacked too. That only happened one time that I can remember.

Very happy with mine. Was a good investment in 1998.

BTW I still run the OEM 16" Alcoa Forged Aluminum wheels. Work for me. Besides, after stripping them and polishing them to a mirror finish, I'm not about to change them but then I carry a pop up, not a hardside so my weight is well within the capabilities of my tires, wheels and cargo capacity.

[msiminoff]

2 MPG better ? VERY IMPRESSIVE !

Yeah, I'm totally blown away by this! I expected expected worse MPG unloaded and about the same (or a smudge better) with the TC on. It's a really nice bonus for sure.

ARB locker are kind of expensive, especially with the compressor. Did you look into E-lockers?

I looked at all of the available options before deciding on ARB. In second place was the combination of TruTrac in the rear and E-Locker up front. I already had onboard air and I wanted to have a bulletproof driveline that had excellent street manners (99.9% of my driving) and was a spool when I need it to be. I felt like I needed to re-gear, and at that point the brand of locking diff I selected really didn't change the total cost all that much.

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.

I also do all of my own wrenching, but I let the nice guys at Rearend Specialties install the gears for me. Their shop does one thing and they do it very well.
There's zero gear noise at all and when I pulled the cover off to do the fluid change the wear marks are full depth and dead-center on the ring gear.

No point in turning over the output shafts and universals when I don't require it...

I have manual hubs too, so none of the front drivetrain is spinning when it isn't needed.

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.

Can't imagine any time when I'd lock either diff' on a hard, dry surface. I'd say there's a pretty good chance that I'll never actually need to lock the front one off-road... it's just insurance.

Still carry my Lewis winch. Sometimes, locked diff's don't cut it.

Ya, I carry a MorePower puller for exactly that reason.

How did you calculate mpg? Did you recalculate odometer difference from real distance?

Um, I divided the number of miles driven by the amount of fuel I put into the tank... I've counted ever gallon of fuel I've put into the truck since the day I bought it.
Yes, my speedo has been re-calibratedand matches my GPS within ¼ MPH.

I don't want an air locker in the back, tire wear becomes an issue...

Tire wear? With an open diff?

Cheers,
-Mark

[theoldwizard1]

2 MPG better ? VERY IMPRESSIVE !

ARB locker are kind of expensive, especially with the compressor. Did you look into E-lockers ? Ford is using them on the F150 and new Expedition/Navigator.

[time2roll]

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.

[cewillis]

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.

[SidecarFlip]

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.

[time2roll]

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.

[cewillis]

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.

[ScottG]

Nice!
I would like to have an air locker for the front but wouldn't get enough use out of it to justify.

[SidecarFlip]

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).

[Kayteg1]

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?

[av8rds]

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!