Ive never had a problem with my Detroit locker on the road, but that could be due to the 37" tires and manual transmission. It drives like a normal bronco. Now with 31s, maybe they would tend to spin more in turns. The only time I ever had to be cautious was in the wetness. And even then, it wasnt all that bad.

That all being said, unless it's a rig that will be used off road a lot, a tru-trac would be the best all around choice. Absolutely nothing to worry about, and still great traction off road. There is no need for a full locker on the street in a normal vehicle.

 

I agree with everything you say here. But so many people think that power is what makes an automatic locker work that I really try to get away from that. When people think that getting on the gas locks it they then think they need to get off the gas for it to unlock. But as you say, it's purely based on wheel speed. It will always unlock if one wheel wants to go faster (like the outside tire in a corner if you aren't spinning the inside tire) and it will always lock when they are going the same speed again (like when you straighten out, or when you spin the inside tire fast enough). So yes, getting on or off the power can affect wheel speed, but it's wheel speed, not power application, that makes it lock or unlock.

It's great to have different people with different experiences and different opinions weigh in on this. I've found automatic lockers to be very streetable (in my opinion), but they can be annoying at best, and a royal pain at times. So I would never say they are the right choice for everyone. You need to really want the positive performance, and be willing to put up with it's quirks. If either of those is not the case, you'd be better off with something else (and a selectable or a gear-type limited slip like you suggest would both be good options).

Also, as GoinBording points out, the vehicle makes a difference. An automatic trans, longer wheelbase, wider track, and more weight on the rear axle all make the quirks of an automatic locker less intrusive. They're still there of course, but it's easier to deal with them. That said, I daily-drove a CJ5 with a manual trans in the winter with a Detroit. It doesn't get much worse than that, and I didn't mind it. So if you value it and are willing to put up with it, even that isn't out of the question. And I had a LockRight in an F-150 SCSB with an automatic and a heavy fiberglass topper. It would frequently squeal the inside tire when starting around turnds, and one time I couldn't get up a wet parking ramp without howling the inside tire to get it to drive the outside one as swell (an open diff would have just walked up that ramp). So they really aren't for everyone.

 

This is an awesome debate with great info. I have never had the auto locker but dearly want to take the plunge. I have had a lot of different vehicles in my 50 years including 3 motorcycles, 4 Broncos, 3 c20's, 2 jeeps, 2 f150's and drove box Van's to semi's. I respect the road every day. I am confident that the auto locker would only be a learning issue for me as the respect is already there.

I don't believe that auto lockers have no place on a daily driver. My daily ride is a 62 mile round trip down a straight highway. But I also ride in the hunt club year round and would appreciate it in the swamp.

I drive a 1996 F150 short wheel base with 5.0 and an automatic. I have 240,000 on my 3.55 gears and I am regearing to 4.10s.

So with that said, I live in Florida with no rocks. Is there a reason for the full case detroit locker over a spartan?

thanks again.

 

I'm not going to get too much into which auto locker is best for someone. The "lunchbox lockers" (like Spartan, LockRight, Aussie, maybe others) are cheaper to buy and don't require a gear setup which makes them much easier (or cheaper) to install. Full-carrier lockers (like Detroit and Grizzly, maybe others) are probably significantly stronger, since the entire carrier was designed to be a locker, and they certainly have a strong reputation. Which should you buy? Up to you. But do keep in mind that since you're regearing anyway the lunch-box lockers lose their installation advantage and you're just comparing the purchase price (of course, luch-box lockers are still easier to take out and go back to an open diff if you think you've made a mistake).

However I would like to hear from people who have experience in mud with a TrueTrac. I'm not so sure that an automatic locker would really have any performance advantage over a TrueTrac in mud. TrueTracs send 3.5x as much torque to the tire with more traction as they do to the tire with the least traction. When one tire's in the air getting zero traction it sends 3.5 x 0 = 0 torque to the other tire. That's why it's not great in rocks. But how often in mud do you have no traction with one tire and good traction with the other? I don't know, I'm not a mudder. But I could imagine that a TrueTrac would pretty much always spin both tires in mud, and that's the best a locker can do too.

 

We have wheeled fine enough for years with open diffs through thick soupy mud up to the headlights. We've found that in mud, tires really seem to matter more than diffs.

 

My experience has been the same; locker in the mud wasn't impressive. I get stuck in 2x4 just as easily as (or close) with open differential, same for sand. Airing down matters more than anything for sand, good mud terrains fix the mud issues.

I drive a lot of rocks (WY & CO), and that is why I was blown away by the locker's performance. There's a lot of chassis twisting where I like to explore, which removes weight from one tire per axle, leaving an open diff'd truck unable to proceed without using momentum. Momentum is fine, to a point, but it's also when most damage occurs. With the locker, I crawl up obstacles, it's unreal for someone like me coming from open diffs.

 

Good to hear real experience! That confirms my thoughts, that in spite of my appreciation of lockers in rocks, and my feeling that automatic lockers are reasonable on the street, I'd still recommend a TrueTrac for the OP, with mud and street driving as the intended usage. Not saying an automatic locker would be a bad choice, just that a TrueTrac would be no worse in the mud and considerably better on the street.

 

My 85 bronco sees mud and some small rocks. With the tru-trac up front and the full Detroit in the rear, it outperformed my equally equipped 94 with open diffs. Both run 37" swampers, and the 94 had 4.88s opposed to the 4.56 in my 85. I'm not talking deep mud, but rather slimey top mud that does nothing but slide around on the bedrock below. Also why skinny pizza cutter tires are popular here: cut down through the mud to the hardpack below.

lots of good info being discussed here