Looking for input on gear ratio and lockers

[BugoutJeep]

I found an explanation from Revolution Gear explaining the difference between chromoly alloys and 1541H. The question was why choose 1541 material over chromoly for this application?

1541H is used since it's a c/clip axle. 4140 or 4340 is just too hard for the bearing surface. Fundamentally not sound for that application. It would wear out the bearing surface in a few hundred miles.

Oh ok. I was thinking the bearing wore out the shaft, not the other way around and I didn't understand, since we have hardness pretty much dialed into whatever we tell the hardener to do.

It's probably something that could be done, but 1541, is just so close in spec to chromoly, that it's probably just not worth it few a few % increase in strength.

 

[JMT]

1999 Jeep TJ. Dana 35 rear & Dana 30. Looking for the right gear ratio and for the best of both worlds. In Montana there is lots of icy roads on and offroad. Traveling to hunting areas can involve lots of highway travel. I'm running 33" tires and right now open diff. with 3.73 gears. 5 speed manual 4.0l (runs 2000 RPM at 65mph). After lots of research on lots of Forums. It gets pretty confusing. Moderate off roading. old logging roads.deep snow and narrow icy inclines/declines. Loose rocky travel. I'm upgrading to chromoly axles front and rear. Thinking about Detroit Trutrac LSD front and rear. 4:10 or 4:56 gear change.

My upgrades already are: RC 4" coil springs, Advance Adapter SYE , Adams drive shafts (front & rear),Core4x4 front and rear control arms (upper & lower),RC adjustable track bars, rear disc brakes

Not going to any bigger tires,no rock crawling (nothing extreme anyways). Not upgrading to a rear dana 44.

I know this has been gone over time and time again but would appreciate your input and suggestions on gears & lockers/limited slip for My driving conditions!

With a Dana 35, don’t do more than a LSD with 33” tires. If you want a locker, you should do a S35. 1541H shafts, NOT chromoly.

For the Dana 30, a selectable locker.

 

[BugoutJeep]

Do these LSDs actually slip when there's too much traction? I've never had a LSD, just selectable and lunch box and lunch box seems like it would be really hard on shafts.

 

[JMT]

Do these LSDs actually slip when there's too much traction? I've never had a LSD, just selectable and lunch box and lunch box seems like it would be really hard on shafts.

No, but if you lose traction on one tire, it will slip. Very good on ice and snow. Not ideal on any other surface.

Lunchbox is not harder on shafts. David Kishpaugh at Jeeps West recommends lunchbox up front on all tire sizes <37” bc selectable are harder on front end components.

 

[BugoutJeep]

No, but if you lose traction on one tire, it will slip. Very good on ice and snow. Not ideal on any other surface.

Lunchbox is not harder on shafts. David Kishpaugh at Jeeps West recommends lunchbox up front on all tire sizes <37” bc selectable are harder on front end components.

Granted I only had a cheap lunchbox locker, but mine in another vehicle with AWD the lunchbox would engage too often. I would be afraid that in 4x4 and tight turns that it would engage. Whereas the selectable, you turn it off until you have to have it.

I think there's danger in selectable lockers, but with good practices I think you would be much easier on your front end, because you would engage the locker less frequently and for short duration. The lunchbox I had would engage, kind of "dynamically" too, which I would think would send a shock through the axle, whereas I try to engage my lockers when my wheels aren't turning, or at least before I start spinning.

The autolocker would have a wheel spinning and then stop very abruptly.

 

[JMT]

Do these LSDs actually slip when there's too much traction? I've never had a LSD, just selectable and lunch box and lunch box seems like it would be really hard on shafts.

No, but if you lose traction on one tire, it will slip. Very good on ice and snow. Not ideal on any other surface.

Lunchbox is not harder on shafts. David Kishpaugh at Jeeps West recommends lunchbox up front on all tire sizes <37” tires bc selectable are harder on front end components.

Granted I only had a cheap lunchbox locker, but mine in another vehicle with AWD the lunchbox would engage too often. I would be afraid that in 4x4 and tight turns that it would engage. Whereas the selectable, you turn it off until you have to have it.

I think there's danger in selectable lockers, but with good practices I think you would be much easier on your front end, because you would engage the locker less frequently and for short duration. The lunchbox I had would engage, kind of "dynamically" too, which I would think would send a shock through the axle, whereas I try to engage my lockers when my wheels aren't turning, or at least before I start spinning.

The autolocker would have a wheel spinning and then stop very abruptly.

It doesn’t engage unless you pull the lever from 2H to 4H. You can do this while in gear up to 45 mph without any noise, totally invisible.

selectable is a different issue.

I wouldn’t worry about either a lunchbox or selectable. They both work great.

 

[gosborne]

For your winter conditions there in Montana that would be a good combination.

Dana 30 and Dana 35. Got 27 spline Chromoly shafts front and rear. 4.56 gears, Eaton e locker in front and detroit trutrac in the rear. Running 33" with a 4" lift and thinking about the next set of tires being 35". What do you think. will 35's be ok with my set up?

 

[JMT]

Dana 30 and Dana 35. Got 27 spline Chromoly shafts front and rear. 4.56 gears, Eaton e locker in front and detroit trutrac in the rear. Running 33" with a 4" lift and thinking about the next set of tires being 35". What do you think. will 35's be ok with my set up?

You're very borderline. You should do a S35 in the rear to be on the safe side. If you don't, you should carry some extra shafts, and if you break one, then fix it, get home, and go to a S35.

 

[Jerry Bransford]

Dana 30 and Dana 35. Got 27 spline Chromoly shafts front and rear. 4.56 gears, Eaton e locker in front and detroit trutrac in the rear. Running 33" with a 4" lift and thinking about the next set of tires being 35". What do you think. will 35's be ok with my set up?

Are your rear shafts 1541H or 4340? 4340 is not the right material to run in a Dana 35 due to its bearings riding directly on the axle shaft's surface instead of a bearing race like how a Dana 44 bearings are.

Either way, those are just marginally stronger than the factory carbon steel 27 spline shafts are... something like 10-15% IIRC. Which means for 35's I'd go with a Super 35 kit which includes 30 spline 1541H axle shafts which are definitely worthy of both 35's and a locker.

 

[Rubicon88]

Dana 30 and Dana 35. Got 27 spline Chromoly shafts front and rear. 4.56 gears, Eaton e locker in front and detroit trutrac in the rear. Running 33" with a 4" lift and thinking about the next set of tires being 35". What do you think. will 35's be ok with my set up?

Depends on you.

I've made 36's survive on a 30 with std axles and an amc 20.
Those were heavy mofo's too with 400 hp and a t18.

If you just want to heavy foot every obstacle probably not very long.

If you have a good sense of feel...absolutely.