Before i start this is all hypothetical. So ive always wanted to do a solid axle swap on my truck either a dana 44 up front or dual dana 60s but this would invovle a lot of work and a plan i have for later when i can park my truck for a while. but untill then if i wanted to swap the gears in my axles now what would need to be done always would like to put a locker up front and an air locker in the rear. what kind of work would i need to do to swap my 3.08 gears for 4.10s or 3.73

 

Doing gears is sort of one of those "if you have to ask you can't do it" things. I've never done gears myself, but I've read up on it quite a bit. It doesn't sound like rocket science, but it takes some special tools, sometimes some extra parts (shims and crush sleeves) a little knowledge and a WHOLE lot of patience. Look on-line and/or in a good shop manual for tutorials, instructions and specs. Then see if it's something you can do.

As far as your plans, if you ever think you might actually drive your truck in 4WD (as opposed to only using 4WD when you are stuck in mud or something) I would strongly suggest staying away from an automatic locker in the front. I had one for a little while. It was really annoying at low speeds and positively dangerous on snow-covered freeways. The torque steer from one front tire pulling more than the other can be extremely difficult to counteract, especially at any speed. Personally I'll never put anything other than a selectable locker (like an air locker) in a front axle.

If you're looking to save a little money, an automatic locker in the rear is much less noticeable, especially in a longer wheelbase vehicle like a pickup or with an automatic trans. I've had Detroits in the rear of a CJ5 and an early Bronco (both manuals), and a Lock Right in the rear of an F-150 (automatic). I wouldn't recommend that for a truck that will do a lot of trailer towing, but otherwise I wouldn't hesitate to put an automatic locker in the rear of any other truck.

 

Along the same theme of what Michel153 is asking, what about a limited slip for the front axle instead of a locker? Plus and minuses?

 

I would recommend putting the air locker in the front and if you want to put a LS in the rear go with Ford's LS or a Detroit Tru-Trac. I also recommend installing a master rebuild kit for each diff when you do the gear swap. It replaces all the bearings, seals, shims etc.
It can be expensive as I just got a quote from a 4x4 shop where I live (Vernon, Canada) and the master rebuild kit for my front Dana 44 ttb was $300 while the rear kit for my Ford 8.8 was $180. They quoted me 2 to three hours labor as well. I was looking into a gear swap from my 3.55's to 4.10's. I don't have the figures anymore for what the 4.10 ring and pinions would cost. I imagine one would need to add a hundred and fifty or more to each diff for a rough estimate of the gear swap cost. Mine is already a LS in the rear so my estimate didn't include installing a LS or locker.

If you're handy with tools and have a place to do it, it would probably be cheaper to swap diffs out from a junk yard. Then again maybe not as I wouldn't do it without putting in a rebuild kit as you never know what you are getting. You also need to replace all the bolts, pins bushings etc for the springs as it is not recommended you reuse them.

 

I don't have any experience with a limited slip in the front, but my experience with the locker made me think through the physics so I could understand what was happening, and from what I know now I will NEVER have anything other than an open diff or a selectable locker in the front axle.

With an open diff, both tires always get the same torque, so both tires pull the same. Of course the problem with that is that the tire with traction can't pull any harder than the one that's slipping. With either an automatic locker or a limited slip, if one tire is slipping the other is still able to pull harder. That's good for getting you unstuck, but it gives you an unbalanced situation where one tire is pulling harder than the other. In a rear axle that gives some torque steer, which can be noticeable in short wheelbase vehicles but isn't much of an issue in pickups. But in a front axle you also get the tire with traction trying to turn the steering wheel in your hands as that tire tries to pivot around the ball joints.

The first time I tried to change lanes on a snowy freeway in my front-locker-equipped pickup, as the left front tire hit the deeper snow between the lanes it lost traction. Before I could catch it the truck had jumped into the next lane (fortunately the lane was empty). On the next lane change I thought I knew what to expect, but it still jumped almost all the way into the next lane before I could catch it.

A limited slip wouldn't be as bad as a locker, only because it's not as good. It can't put as much torque to the tire with traction so it can't wrench the steering wheel as much. But the physics are still the same.

Of course if you aren't ever going to use 4WD when driving at speed, then it's not really dangerous, but only really annoying to have the steering wheel pull back and forth as the tires swap traction. So for a rock crawler or a mud truck I could see it being possible to live with something other than an open diff or selectable locker in the front. But if you ever plan to use 4WD on snowy roads, or to drive fast on dirt roads, I'd stay away from anything that could give an unbalanced pull.

 

Thanks Bob. That makes a lot of sense. And yes, I do plan on running 4wd on snow. We don't get it that much, but when we do it can be a while before things are cleared up.

 

Anyone have thoughts on a lunchbox rear locker in a pickup? Something like a Aussie locker or a Spartan locker? The prices are more attractive than any selectable lockers, and the ease of install is very appealing (no gear setup required).

 

I had a Lock-Right in the rear axle of my '95 F-150 for about 110K miles and had no trouble with it. Most of my driving was typical suburban commuting, but I made at least four 2,000 mile trips hauling my slide-in camper and towing a Jeep (total load including truck around 11K), and another 10K miles or so just carrying the camper (no Jeep in tow). Along with the other miscellaneous use a truck gets put to, I didn't beat on it but I didn't exactly baby it either.

I certainly wouldn't hesitate to do the same thing again in a half ton (I can't speak to it in a 3/4 or 1 ton). Although I might go with something like a Detroit if I was planning on doing much serious rockcrawling.

And as I mentioned before here, I wouldn't suggest a locker at all if heavy towing is a goal for the truck. Lockers give you one wheel drive in corners (until you spin the inside tire fast enough to catch up with the outside one) and that doesn't work so well when starting on a turn with a big load on the trailer and not much extra weight on the drive axle.

 

Thanks. I don't tow much any more, in fact I don't even own a trailer at this time. Going to flat bed my truck before winter to haul two snowmobiles (around 1200lb on the bed, my flatbed will weight less than factory bed too) on the weekends but no trailer. Locker would be fun in the summer/fall, and since I don't dd my truck I am willing to make different compromises than others. I am going from cheap Chinese P235/75R15 tires to BFG AT 33x10.5R15 tires, so I may very well not need a locker at all for the wheeling I occasionally do, mostly just curious.

 

Some people think a locker isn't streetable enough for the rear of a daily-driven pickup, but I'm not one of them. Lockers have their quirks, and I wouldn't put one in my wife's car, but for anyone who wants a locker (let alone needs one) the quirks aren't that bad to deal with.

The worst issue I had with my pickup was starting around corners. A locker only drives the inside tire on a corner, so I ended up spinning a tire pretty frequently (and with the BFG M/Ts and A/Ts I had on that truck, it wasn't very quiet!). It was worse obviously when the pavement was wet, or had loose sand, or going up hill. Once I was driving up a parking ramp spiral on a rainy day and I couldn't keep moving unless I spun the inside tire enough to pick up the outside tire as well. But generally it wasn't too much of a problem, I just couldn't start fast around corners.

Driving in snow it's a mixed blessing. It helps you not get stuck, but it can be easier to swap ends if you get on the gas too hard. Again, I got used to it and had no trouble living with it.

Other than that it's just minor annoyances as you get some noticeable torque steer when you get on an off the gas in curves. An automatic trans damps that out quite a bit, and the wide stance and long wheelbase of a fullsize truck really tone it down, so it was hardly noticeable in my F-150. But the Detroit in the rear of my CJ5 could be a real handful on a two-lane mountain road.

However, if I ever decide a better diff is in the budget for my F-250 Crew Cab I don't think I'll get a locker. In a bigger truck like that I don't think it's as necessary, and I wouldn't want to hurt its ability to tow a trailer. I think I'd go with a True Trac there.