Detroit locker posi unit??

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highwaystar

highwaystar

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Has anyone used these? Know much about them? I have one in my 68 cuda. It seems to have alot of slop in it. 1/2 driveshaft turn in gear. They throw out of posi when you corner. Do they typically have slop in them due to that feature? Is it a case of bad spyder gears? or do they have something different in them? I never have worked on them other than putting the ring and pinion in some time ago. What is the most dependable posi unit for street and strip with a 4 speed and slicks?
Thanks for all replys..
T.J.
 
First off, let's get you straight on the terminology. A Detroit locker is not a posi. A posi is a limited slip unit either clutch or cone type and "posi" is a General Motors term. "Sure grip" is Mopar's term for the limited slip unit. A Detroit locker is not a limited slip unit. It has no clutches or cones. It is a locker, just as the name implies. What it does is lock the axles together and make the rear a spool and unlocks the axles around a turn.....UNLESS you go around a turn under enough power to keep the axles engaged. Yes, they typically have more slop than say a clutch or cone type sure grip. That's just the design. They also make noise when engaging and disengaging. Perfectly normal. There are Detroit "Soft Lockers" that make less noise but they still make noise and function the same. They are very stout and reliable, but can be somewhat dangerous in snow and ice. The wheels can slip enough going around a turn and cause the unit to stay engaged and cause the car to "push" through the turn. That ain't too good. As long as you drive them carefully with that in mind, you probably won't have a problem.

Oh, and as for the most dependable unit.......I'd say you have it hands down.
 
What Stroker said, my opinion

I can not imagine that a Detroit Locker would be a good choice for a street CAR. A friend of mine used to have one, "back in the day," in his then -new 70 Chev 3/4T 4x4. Going around a corner, when it FINALLY decided to unlock, it would CLANK and actually sometimes "jerk" or "move" the back of the pickup. I was always kidding him on "when it would break" but it lived on for many many years.

They seem to be strong and tough, but I would not want one in my STREET CAR.
 
Hey thanks so far guys for the good info. Here is where my problem is. On a stout motor with the 4 spd. It has enough slack that when dropping the hammer on it with that slop, It is putting alot of unneccesary twist on my driveshaft, pinion gear, etc. You can actually feel it pull right going thru the gear box under hard acceleration. It feels like the driver side axle is broken, yet it will lay "posi's" down on the road with the radial drag tires. The rear suspension is fine. I thought that was the problem at first, and have just put the new Caltracs in with mono leafs and shocks and new calvert spring perches, and the problem is still there.
 
I think Id opt for an air locker. At least that way its always open until you air it up.This should help with corners and noise. Get to the track,air it up and you now have a locker.

I have an electrically activated locker in the front diff of my gm pu,and the only time it is a bother is on tight turns on pavement.Makes the tires bark!
 
Just pull that pup out and send it to me. I'll put it to good use.
 
My thought is that it is damaged. I use to hear it release around the corners, but haven't lately. That noise never bothered me. Its the slop. I think it is too much. Maybe a automatic with a stall converter would take up that slack, but 4 spd. you can't have it off the line or **** breaks. Anyone know about working on them???
 
I got a locker in my amx, it makes a bit of noise around corners, once you learn to drive around the corners with a bit of gas it will stay locked up. So far it has held up and it gets beat on pretty good
 
I have had a Detroit Locker in my Ferd for over 15 years. When I ran the 5 speed, I noticed the slack too. That is just the nature of the beast. You can always tell a car equiped with a locker by just rolling the car back and forth 3" with the car off and in gear. When I switched to an automatic, I stopped noticing the slack. You can still roll the car back and forth 3" with the car in park.
 
Yeah they are quite easy to service. I've done quite a few. If I can figure it out, a chimp can do it.
 
The driving is fine. I am talking about drag racing. Is this type of sure-grip not reccomended for racing with 4 speeds. I need to reach out to my fellow racers on this...
Street driving is fine, but when you get to concrete with slicks it can't be good. Is the air locker a feature I can add to mine to take the slop out?
 
If your drag racing, you need a spool, if its street/strip you need a good clutch type sure grip. Detroit lockers will break in drag race use, they are mostly a round-track differential. And they SUCK on the street
 
Slop is normal, just stage your drive line before you drop the hammer. I run two of them in my street driven 4x4 not a problem. As far as ARB's go I'd rather have my Detroit's don't have to worry about and air line braking or a compressor going out at a time when you need it most.

Oh only thing better than a Detroit is a spool.
 
That's what I was looking for. They suck for drag racing. I don't want to run a spool. So what is the best after market clutch sure grip out there?
 
replicaracer43 said:
If your drag racing, you need a spool, if its street/strip you need a good clutch type sure grip. Detroit lockers will break in drag race use, they are mostly a round-track differential. And they SUCK on the street
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ALL three of the big three used detroits in cars and trucks at one point. As long as you know how to drive, you ain't got no problems.
 
Never seen a muscle era Mopar with a factory installed detroit locker... They were all the clutch type sure grip, untill they went to the cone type somewhere in about 1969. The clutch type is what you want, find a good used unit, install a new set of clutches, and you will be set!!
 
replicaracer43 said:
Never seen a muscle era Mopar with a factory installed detroit locker... They were all the clutch type sure grip, untill they went to the cone type somewhere in about 1969. The clutch type is what you want, find a good used unit, install a new set of clutches, and you will be set!!
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Those that had the Dana 60 it was an option. Ford used it more than anyone else, but they all did at some point.
 
The Power Lok posi is about the best. The next one would be the Eaton. They are clutch type, and almost as good as a Power Lok. Read the tags that come with the Eaton. Do NOT use synthetic oil, per Eaton. I've installed hundreds of them, and probably close to 1,000 Detroits, mostly in 9 inch Fords (stock cars).

Russ.
 
highwaystar said:
Are the new Eaton posi units a clutch or cone type sure-grip?
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The Dana Power Lock is the absolute best in terms of a clutch type posi.....sure grip. lol It acheives damn near 100% lockup. It probably is 100% in a straight line. I believe Eaton does make it, but don't get confused and get the Track Lock. They SUCK. The Power Lock is what you're lookin for.
 
The power lok is not like the detroit locker is it? and this will fit into an 8 3/4? not just a Dana?Thanks guys for the great comments.
 
The Power Lock is a limited slip clutch type differential. Power Lock is the brand name and has no bearing on the type diff it is. Yes, they are available for the 8.750.
 
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