It's Thanksgiving. Happy Thanksgiving to you.

I'm at work with my fellow skeleton crew tonight and to pass the time I'm window shopping for a possible next year purchase. This would be for my '78 Bronco in my signature. My '78 Bronco is not a DD. It'll be an occasional ride to work if I feel like it, but ideally it'll be for relatively mild weekend fun (crawling or mud) or perhaps to take camping next year.

It still needs lots of work. It currently has the factory setup, Dana 44 up front 9" in the back with 3.50 gearing. Both differentials are open as far as I can tell with lifting up each end and spinning the wheels by hand. So, I've been browsing websites and looking at lockers, spools, LSD's, yadda yadda, and I'm trying to decide what I'll eventually go with. I don't plan on anything extreme with this Bronco, this is my first offroad rig and I'll grow it with my offroad ability and desires. I don't want to go all out on it and then find out I'm not into offroading as much as I thought and then have it sit around as a reminder of how much I wasted on it. I know those are usually the first words someone says right before they go down the rabbit hole and next thing you know they have a purpose built buggy.

I know the best possible setup would probably be a selectable locker front and rear, but that's obviously spendy. I'm trying to keep cost minimal, but still get some good performance offroad. After a day or two of browsing I've come to the thought of a lunch box locker front and rear since I have two open differentials. I know lockers of any sort aren't ideal for the street, but like I said, street use would be minimal. It wouldn't be an issue up front until I locked the hubs, which would be great. The only concern I see for street manners using lunch box lockers vs a LSD or leaving them open would be using the Bronco on camping trips since it'd see some highway use. I know they're not ideal for snow and ice either, but having driven these old trucks since I've been able to drive I've learned to adapt my driving style as needed, so if that's what it takes to not die while driving it in the snow and ice if I decide to do that, then that's what I'll do.

I'm also wanting to switch the gearing from 3.50 to something more along the lines of 4.11. I know if I do that on the Dana 44 that I'll have to get a different carrier, which again adds to cost, though I'm sure that's minimal if I put some effort into a salvage yard search.

Anyone have any opinions on this setup? I'm open to ideas. I'm hoping to one shot this thing and not have to try a few setups to get something I like. So as of right now I'm thinking something like an Aussie Locker/TORQ Locker front and rear with 4.11 gears and 35's.

 

I have tons of thoughts on it! Here is a thread that I wrote up a while ago that might help. https://www.ford-trucks.com/forums/1...erentials.html

For a short answer, I think an automatic locker in the rear for a street/trail driven truck is great. There are handling quirks on the street, but they aren't bad IF you value the performance on the trail and are willing and able to "drive to the vehicle" (people who want the vehicle to drive itself without the driver needing to think could get themselves in trouble).

I only had a locker in front for a little while in an F-150. I don't think it's at all necessary for mild fourwheeling, and the handling quirks are MUCH worse. I wouldn't suggest one there unless you are planning on doing pretty hardcore stuff and are NEVER going to use 4WD on the streets (which I do pretty frequently in Minneota winters).

For mild use I'd suggest leaving the front open for now. If you find you need more traction, save up for a selectable.

 

The neurons must be firing a little slow this morning. I'll blame it on too much turkey yesterday. After I posted that it slowly sank in that you were also asking about changing gears. That doesn't need to change my advice, but since you are going to most of the expense of a front locker install with the gears anyway, I might suggest putting the selectable in front right from the get-go. Yes, it's a little more expensive, but it does save you the (admittedly low) cost of getting a new open carrier for the lower gears. You could still go with open front (I've done a lot of moderate 'wheeling with an open front). And I still wouldn't recommend an automatic locker.

And on the gear ratio, what engine and trans? My '71 Bronco has a 302 and a 5 speed OD manual trans. With 4.10s and 33s it's great on the highway, but a bit of a dog accelerating, especially with any load. I have an Atlas 4.3:1 transfer case, so it's fine off-road. But for a vehicle that isn't going to get a ton of street use I'd definitely go lower than 4.10s with 35" tires. At the very least 4.56, if not lower. And lower yet if you have a 302.

 

I appreciate your responses! I've read your thread and all the comments as well. I've read a gazillion other posts on various forums and, as I'm sure you know, you can seem to find information to support any idea you have which can make it difficult to come to a good decision without first hand experience.

My Bronco has a 351M, NP205, and a NP435 with that deliciously deep granny gear. The 351 has a couple of bolt on upgrades, but appears pretty stock. I've only had the Bronco a few months. When I got it it had 31's. I picked up a set of used and very worn 35's to try out to see how 35's would fit and look. It's definitely a noticeable difference with the 3.50 gearing. My concern with going deeper than 4.11 is the possibility of straining the motor on the highway if I take it camping. I don't mind keeping it around 65mph (my wife might hate it when the speed limit is 80 for a portion of it) on a 2-3 hour drive if that's doable with a 4.56 without running too high of rpm. I know for offroad that it'd be better with 4.56 or 4.88. I've got lots of time to figure it all out.

My thoughts on the auto locker up front was that I'd only use it offroad since I have part time 4wd with the NP205 and selectable hubs. I've heard of people using 4wd and only locking one hub to sort of simulate an open diff. We do get snow and last year was a pretty decent year, but I'm sure Idaho is nothing like Minnesota. I'm considering doing this in steps. I could toss the 31's back on and get an auto locker for the rear and leave the 3.50 gearing for now and then once I decide on what to use in the front and other things (possible lift, tire size) I can move onto the gearing change. Its gonna be a slow process.

 

With a 351 and no overdrive you definitely don't need to go as low as you would with a 302 and an overdrive. 4.10s will put you at about 2500 rpm at 65 mph with 35s. 4.56 would be 2800. The 4.10s might be a better choice for you (although you may find yourself needing that 1st gear a few times).

The problem with a front automatic locker is torque steer. As you get on and off the throttle it will pull the wheel pretty violently. This would be even worse with one hub unlocked. The only reason to do that would be if 2WD wouldn't get you around a tight corner and both hubs locked plowed you straight. It's also worse at highway speeds. Like I said in that thread, put one front tire into snow and the torque steer will put you in the next lane before you can react. If you do put an auto locker in the front plan to only have 2WD for driving in snow (you can use 4WD at low speed to get you out of the ditch or up the hill).

 

For your uses I think a pair of Detroit lockers would fit the bill. They are cheaper than selectable lockers and more reliable. I have heard a front locker can create some steering issues when in 4x4 on snow covered roads but I haven't driven a vehicle with a front auto locker in the snow yet so I am not sure. I will find out this winter though. Just a rear Detroit and an open front can get you just about anywhere you need to go and will still do good on snow covered roads.

 

Not "steering issues", a front auto locker is scary dangerous on snowy highways. Like the vehicle jumping abruptly 10 feet to one side or the other. I experienced a front locker on a snowy freeway for literally 1.5 miles. It was so bad I shifted into 2WD and never used 4WD on the highway again until I had removed the locker.

Automatic locker rear and open front is really good, but eventually (if he keeps fourwheeling) he'll want a front locker and when doing front gears is the right time to do it. (I've been 'wheeling 26 years without a front locker, I think I'm finally going to get one this year, so it's not like an open front will need to be "fixed" soon.)

And a lunchbox locker is every bit as good as a Detroit for moderate use, while being a lot cheaper and easier to install. A Detroit is stronger (and a Yukon Grizzly might be stronger yet). But for most people the lunchbox lockers are plenty strong.

 

Lunch box lockers are great if you are on a budget. I have Spartan lockers in my jeep and they haven't given me any trouble, I have also installed Spartan and Aussie lockers in other peoples vehicles and I haven't seen one fail yet. I prefer the Spartan over the Aussie because it is easier to install, it comes with a new cross pin, and it is cheaper. Keep in mind a Dana 44 has a carrier break so to install 4.10 or lower gears you will need a different carrier, that would be a good time to install a selectable locker if you wanted to. You could just lock the rear for now with a lunchbox locker and leave the front open until you regear then put a selectable in If you think you need one.

 

as Bob said, skip the front locker if you are going to do any on road driving. they are real dangerous unless is is a selectable locker that can be turned off for on road driving.
i watched a guy wreck a 79 bronco because the driver side axle universal snapped. when it did it broke his wrist spinning the steering wheel to the passenger side, and then it went head on into a tree at 35 mph.

 

I vote leave the front alone, leave it open the way it is. Even for an all out mud truck or trail rider I vote to leave the front open unless you fork up big money and get selectable lockers. Even in the wife's mega truck on 2.5 ton Rockwells we opt to leave the front open and we welded the rear. For a daily driver of vote open front and some sort of locker in the rear. I have some sort of locker in the rear of my Cummins and I wouldn't have it any other way, the Cummins is a DD in Michigan and you just need to make slight adjustments to your driving in the snow. Let's be honest that 351 is no power monster and you wouldnt really have to change your driving style much at all. 9 times out of 10 you won't be able to tell the difference

 

I think I'll go with a lunchbox in the rear and save my decision on the front for when I do a gearing change. This will be a slow process, so I'll have time to work out the details. I got this Bronco back in September and its a side project. This is the first 4x4 I've worked on and my goal, unlike I've done on my F100, is to do the work that it needs done by myself. For most that might not seem like much, but I literally have one Craftsman 108 piece tool set and a few other odds and ends, so I have limitations at the moment. I'm hoping to get out of this apartment and buy a house next year and step up my tool collection in order to get things done, that's when I'd start doing this. I rebuilt the front double cardan drive shaft a couple weeks ago and that was a challenge, however, the Bronco no longer sounds like a scary roller coaster when its in 4wd. Click click click click.... weeeeeee. lol Part of the appeal of the lunchbox type locker is that I'll be able to install it myself as I'm learning the ins and outs of this thing.

 

It sounds like a solid plan, I wish you luck

 

A Spartan locker for a Ford 9" runs less than $250, I also recommend 85w140 gear oil to quiet down the clicking noise. The ones in my Jeep are very quiet the only time I can hear a faint clicking noise is when I am coasting around a corner with the windows up and the radio turned off.

 

It's not a DD. Man up and put a pair of Yukon Grizzly lockers or Detroit Softlockers in. Whatever your axle guy likes better. Way cheaper than selectables, and I like them better off road.

I don't think a lunchbox will make a good 1st impression for a new wheeler.

 

I used to have a 69 Bronco factory equipped with clutch type "posi" in both ends. It was very twitchy on slick or snow covered roads. I finally wound up putting Detroit Tru Tracks in both ends, and while they are not a true locker they worked extremely well for a double duty rig. They where quite, no torque steer, they just pulled well in the direction I pointed the tires both on and off road.