So I have been reading on a bunch of different forums about Detroit Lockers under city driving conditions. My truck is an 87 F250/F350 with a 6.9 diesel. I am currently in the process of swapping out the TTB front axle for a Dana 60, that has 4.10 gears. I have a spare rear axle with 4.10 gears as well but it needs a new carrier. So I was planning on pulling the carrier out of the rear axle that is currently on my truck and regearing it to the 4.10 from 3.55. I figure while all that is being done, if ever I was to put in a locker now would be the time to do so. But I hear they are terrible while doing city driving. My truck gets taken off-road occasionally, but still does a lot of city driving in between. But it is not a daily driver, more of a weekend warrior/work truck. If I put a locker in it would I run into a lot of problems or would it drive kinda like normal, just slower turns. The truck has a manual transmission if that makes a difference.

 

Lockers, just like they sound, lock the rear wheels together for the most part. So if it's a little slick outside and you turn, it's very easy to lose traction. Conversely, if it's dry and you do a sharp turn, you'll squeal the tires as one drags across the pavement. What you want is more of a limited slip set up. Where you have a little play before the wheels spin together.

I think what you're looking for is this: Detroit Truetrac

This is what quite a few people here have opted for after their factory limited slip has worn out.

 

I personally wouldn't run a locker on anything that sees regular street driving. They're rough and jumpy during turns.

2nd the TrueTrac option

 

true trac is the way to go. Got it in my 88 F150 and never once run into an issue and I offroad once in a while and she almost never looses traction minus driver error.
Trav

 

Sloppy thirds! Slow forth!

I also choose the Detroit/Eaton Truetrac.

-Enjoy
fh : )_~

 

Detroit locker is the best there is. On a long wheelbase truck they are fine on the road. Something like a jeep they are a pain... But you say you only go off road occasionally so a trutrac is more appropriate for your situation.

 

+1 on the Eaton Truetrac.


Put one in my 96, big improvement plowing snow and towing trailer.


Todd

 

Disagree 99.999%


It'll be rougher around the edges than it was before. You'll chrip the tires more when turning. You'll never do the one wheel peel mid way through taking a right or left into traffic. You'll be able to make it up more dirt roads and what-not without touching the transfer case lever. The harshness it completely worth it. The biggest day to day benefit is that you can use more throttle in left/right turns so it's easier to not cut people off (more power to the ground = get up to speed faster). Once you have a locker out back and get used to it you'll want one in everything you drive. The traction is so worth it.

 

Have you ever run a truetrac? It really is an awesome piece of equipment, even with a wheel in the air you can get the grounded wheel to dig 9 times out of 10 by using the brakes. It's 90% of a locker with none of the downsides. Locked is locked, which is king if you need it...but the clutchless lsds are not junky like clutched diffs.

With wheels on the ground it'll always seek traction.

 

I've never used a Truetrac, but from what I understand about it, it would be my first choice for a primarily street-driven 3/4 ton (or heavier) truck. Great road manners, very good performance in low traction situations.

I would only go with an automatic locker if I wanted the best possible performance in low traction, or if I wanted to save money and get a lunchbox locker. In either case I'd know that I'd be giving up road manners for what I'd be trying to gain.

That said, I don't really think the road manners of an automatic locker in the rear are that bad. I drove a '95 F-150 SCSB for about 9 years and 100K miles with a Lock-Right. The biggest issue I had was squawking the inside tire on turns. Because unlike what was said above, automatic lockers usually UNlock, giving you only one-wheel drive (the tire that is turning the slowest). So it's hard to start around a corner without spinning the inside tire (once the slower tire catches up with the other tire the locker will lock and drive both tires, but the bad road manners here are due to it driving only one tire, not to it locking the tires together). This problem is bigger when towing a trailer, which I why I'd tend to stay away from a locker on a 3/4 or 1 ton truck.

The second biggest issue is related to driving in snow. When you spin the inside tire and the locker engages, it will do so rather harshly, which can abruptly break the outside tire free and the truck can spin out. This can happen with a Truetrac too, it just doesn't seem like it would happen as abruptly, so it would be easier to catch. Again, I drove that F-150 through 9 Minnesota winters, and never had any problems with it being too easy to spin out. I've had a lot more trouble with factory limited slips in snow (they don't disengage, so they tend to make you skid a tire whether you're on the gas or not). But I would think twice about having a rear locker in a truck my teenage kid or wife might drive.

And as noted, these issues are less bothersome with a longer wheelbase (and an automatic also tends to soften the issues). I also drove a CJ5 with a Detroit and a manual trans. The road manners in that were bordering on objectionable for me (given its primary use as a rockcrawler I was willing to put up with it). But in the longer pickup it really isn't all that bad. But I'd still recommend a Truetrac unless you expect to be putting tires in the air very often.

 

Why not a selectable locker? Flip it on when you need the traction. Flip it off and run open diff when on the street and don't need the traction.

 

Selectable lockers are ~twice the money of a TrueTrac.

-Enjoy
fh : )_~

 

True, but it eliminates all this ^^^^^. I found one for 800 ish. Detroit's are a bit more but you get what you pay for.

 

Selectable lockers are great for getting stuck. People drive as far as they can with it open because making tight turns on a trail with a spool sucks. Then when they're finally stuck they flip on the locker expecting one more tire to be able to get them off whatever they're on or out of whatever they're frame deep in. The results are predictably underwhelming and a winch, come along, or friend with a tow strap is usually needed at that point.


I don't see what's so fun about that. It must be a Jeep thing.


Detroits and lunchbox lockers are the best of both. When you're not on the gas you can turn as tight as you want but when you're putting power down to try to get over or through something it locks up. The decrease in road manners is well worth it IMO.


The biggest benefit to a selectable is not having to explain how it works when you tell someone you have a locker and they say "you mean like an ARB?"

 

What arse_sidewards said about selectables. True, they give you an open diff when you don't need the traction and a spool when you do, but you need to be on top of when to switch them to use them effectively. I could see using them in a truck that would see only pavement (leave it unlocked) and deep mud (always have it locked). Or a rock crawler that doesn't really get stuck anyway (it just gets where it can't go anymore, lock it then). But for a rear axle I'd prefer an automatic locker or a Truetrac (I'll NEVER put anything but an open diff or a selectable in a front diff though, the handling issues on snow-covered freeways are way too big with automatic lockers, and not worth the risk with limited slips).

I will nit pick arse_sidewards' semantics about when an automatic locker locks up. It does not necessarily lock when you get on the power. It locks when both tires are turning the same speed (and then unlocks when one tire tries to go faster than the ring gear). So if you get on the power enough in a turn to break the inside tire free, yes the locker will engage. But if you don't spin the inside tire it will remain disengaged, even though you are powering the inside tire.