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Locker use notes - Ram owners comments.

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Dave Fritz's notes: My rear Lockright:

Installed: 08/31/95, 17552 Mi, 496.4 Hr

The LS option was not available when I ordered my 2500 Ram, so I installed a LockRight (Detroit Lockers weren't available then either). The LockRight for the Dana 80 Hybrid in my Ram 2500HD cost $430 plus $70 for gear oil, gasket material, and a mechanic friend with tools and a rented garage for the installation. As it turned out, no special tools or skills were needed, but the garage was much better than trying to do work in my driveway. The LockRight must be installed in an open differential, it will not fit in a limited slip differential case.


For serious traction, the lockers are unbeatable but the do cause some noise and funny handling on paved roads. My LockRight is much more effective than the limited slip in my F250 and the LS in Sue's 2001 Ram 2500 for traction,  but it doesn't behave as well on the pavement.  With 72K on my LockRight (Sept. 2001 photos above) it appears that the LockRight can stand up to the diesel engine (on and off road) if the driver uses reasonable care. Wear appears to be minimal, and the locking teeth are still sharp.  I have heard of people breaking the differential cross shaft or destroying the LockRight, but I don't know what the circumstances of the failures were. I do know three others running the Lockright behind the Diesel and V10, and none have experienced failure. I suspect that the LockRight would not survive full throttle burnouts on pavement with enhanced engines, nor could it withstand full throttle, wheel spinning, rock/mud racing. Powertrax recommends using a hardened cross shaft for "extreme" conditions, but my OEM cross shaft has never shown signs of distress and I have put some tremendous loads on the rear axles. If the LockRight  breaks, I will put in an ARB air locker, which is now available for the D80 and is able to remain open for pavement and lock when needed off road.

Locker Quirks:

With the LockRight (and Detroit Locker), the rear tires MUST be the same size and inflated equally to avoid "locker steer" on throttle transitions. I can tell when there is a 2psi difference in rear tire pressure. My truck is very nose heavy which helps minimize the steering effects. Lighter trucks and shorter wheelbases will experience more locker induced steering.

Expect pops, bangs, and clicks from the lockers. In easy turns they click. In paved parking lots the truck will often get the hiccups as the locker rapidly locks and unlocks. A loaded truck on dry pavement will occasionally produce a loud BANG as the dog clutches align and lock in turns when power is applied.

Some say that the lockers are dangerous in snow and ice because the rear can break loose and slide sideways.  I have found that most of the time, a tight limited slip differential is worse about sliding than the locker has been.  Snow is fun with a locker, with good tires nothing stops you.  Proceed very carefully however on icy mountain roads or the truck may suddenly swap ends.

LockRight FAQ's (Also: see the PowerTrax FAQ page)

>  I got a 4x2 open  diff (4x1 :) and don't do much off roading, but seems it's way  too easy to spin a tire.

I had a 2WD F150 with limited slip many years ago.  It was a compromise before I could afford 4x4.  A 2WD with a traction differential and good tires can do almost as well as as an open diff 4x4. I drove through a lot of snow with that truck in OH, PA and WV. I also got stuck in snow, in mud, in dirt, and in sand.

> I've done lots of research on lockers  and heard they can pop and bang, but are simply unbeatable offroad.

All of the above is true.

Normal light clicking during turns is audible above the diesel, but not obnoxious. The occasional loud bang from the rear while on pavement is much louder, about like a u-joint letting go under load. A steering twitch usually accompanies the bang. The bang/twitch doesn't bother me, and my wife only jumps when it catches her by surprise. Off road is where the lockers are truly in their element.

> How well does yours do on the road?  Do you even know it's there when you're on the highway and does it just pop and stuff when going around town and parking lots.

I know it's back there. Even with a heavy diesel truck, throttle changes affect the steering noticeably when the tire pressures aren't EXACTLY equal. Unequal tire pressure, or tires with slightly different diameters will produce a bang about 5% of the time after completing a turn. If the tires are identical (use a tape measure on the circumference to find the best pair), bangs are less frequent. With a TST enhanced diesel (600+ ft-lb at the flywheel), I can get noticeable torque steer with large throttle changes if the tire pressures differ by more than a few psi, and the torque steer is strong enough to require significant steering wheel corrections when the tires differ by more than 4 psi.

The truck occasionally gets the "hiccups" while winding around a paved parking lot. If I get the throttle in just the right spot, the locker rapidly locks and unlocks producing an obnoxious surging/bucking/banging.

Changing throttle, too much throttle, or too little throttle in a tight turn will produce a steering twitch and locker bang.

Tire scrub on the inside wheel is common in gravel or in a tight uphill turn on pavement.

A locker will cause the truck to increase speed in turns.  Explanation:  with an open diff, the ring gear turns at the average speed of the two wheels.  In a turn, the inside wheel slows down and the outside wheel speeds up, but the average is fairly constant and the vehicle covers about the same amount of distance per driveshaft revolution regardless of the turning rate.  With a locker, the inside wheel turns with the ring gear while the outside wheel overruns.  The result is that for each driveshaft revolution, the inside wheel covers the same distance (regardless of the steering angle) and the front of the truck speeds up as a turn gets tighter in a crack-the-whip type of effect because the front wheels and the outside wheel must travel farther than the inside rear wheel.

I can usually hear the dog clutches click when turning. It took my wife a while to adapt to the noises and handling, but we both love the traction. After a while, we adapted our driving techniques to minimize the parking lot and cornering "surprises".  

John Donovan's Lockright Installation and Use Comments

Subject:  Re: RAM diff locker in a Chrysler 9.25" rear axle
Date:      Tue, 12 Nov 1996 15:32:29 -0500 (EST)
From:     John Donovan
TO:        Ram Truck Mailing List

> I think this locker will be a good idea since I only go off road occasionally
> and it seems so easy to get my 4x1's one tire spinning regardless of surface.
> Looks like I'll be paying around $330 and doing the install myself. Looking
> at a few extra bucks for a new diff gasket and fluid.

I put the LockRight in 2 weeks ago, so I can answer this 1st hand. You need permatex blue for the gasket material, and let it dry 1hr min before putting gear oil in. Also consider spending the $$$ on synthetic gear oil. You will need 2L of oil, get the 3rd L just in case... =)

> Basically, I'm looking for any last minute comments before I purchase something
> for $300+. I know the unit "clicks" when turning, but I'm hoping it's nothing too
> ugly sounding.

Normal driving you won't hear it... parking lots... lots of click click click

> Any comments/opinions/last words????

Notes from my install...

#1 there are/were no thrust washers under my side gears.. you MUST have them to get the parts into the correct spacing and proper functioning. Go to a dodge dealer and get the "thrust washer service pack" it's about $30 and has 4 sizes in it, I used the "square" ones, which are the 3rd largest size .039" I think, and it brought me nicely into spec.

#2 get a set of dial calipers to measure the parts after install... $30 at Heckenger, and will help you confirm you did it right.

#3 when you to the "test" to see if the tires ratchet properly, put the wheels back on as you cant get enough force on just the brake drums to test.

#4 get a second set of hands around

#5 there will be spacers for the "thin" c-clip axles... you have a thick c-clip axle so you will have to shim washers left over.

#6 a magnetic pickup tool makes getting the 2nd c-clip back on MUCH easier

the instal is SUPER easy (IMHO) and if it wasn't for the taking it back apart to get the thrust washer in it would have been < 1 hour to install.

Now how do things change as far as on street manners:

#1 slight power in tight turns will cause wheel chirp, hard turns and lots of power will cause you to sound like a 16 year old in a hemi-cuda at a drag race... nuff said.

#2 if you are cruising along and quickly get off the gas, or put the clutch in you will hear a LOUD "BBAANNGG" from the rear, this is the pinion shaft catching up to the holes in the drivers... be more gentle with the throttle or you will wind up breaking things.

my readers digest version of my install...

Subject:  Re: Dana 80
Date:      Thu, 18 Jun 1998 11:38:32 -0400
From:     John Donovan <>
To:         cummins
> Has anyone on the list installed a locking diff in their Dana 80?
> Which units were installed and can it be done by your average "do
> it yourselfer". Any info would be most appreciated.
if you have a factory limited slip, or if you are installing a locker that requires removal of the carrier, then its really not a DIY job. It can be done, but, working on the dana axles requires some special tools and the tolerances are VERY tight and if you miss the tolerances the gears will be destroyed in short order.
The lockright is a self installable locker, I've done one, and it took about 3 hours the first time I did it, but I'd bet the next one I do would be < 1 hour.
very easy to put in, and very effective.

> How does that thing behave in on pavement use?

there are a couple of "quirks" that the lockright has...

It locks when there is torque on the driveshaft... doesn't matter if its acceleration, or deceleration, forward or reverse, if there is torque on the shaft, it will lock the diff. When its locked a wheel can turn faster than the driveshaft is turning, but not slower, so in a corner the inner wheel is locked and the outer will be "over driving", or turning faster than the inner. When this over driving occurs there will be a "clicking" from the rear end which is normal, but some people find it loud enough to be annoying ( i didn't). The lockright will also add some degree of under/over steer depending on what the truck is doing, but its not as bad as a detroit, and is quite reasonable.


Chris Siano's Locker Comments

Subject: [RAM] lockers
Date: Tue, 4 Mar 97 13:42:59 EST

> Could someone explain about lockers and how they would enhance my v-10
> extended which is used mostly for hunting and not heavy 4 wheeling. also cost
> and how hard to install. Thanks.

Ok, everyone know what happens when one wheel of a drive axle is in the air, and one is on the ground. The one in the air spins.

A locker prevents this from happening. Picture an old stone grinding wheel. You know, big heavy disk with the radial grooves in them? Well, instead of little grooves, make them teeth, so that two disks placed side by side will mesh the teeth. OK?

Now take four such disks. One disk is placed at the inner end of each axle with the teeth facing in. The other two are between the axle ones facing out. Little springs hold the inner plates against the outer ones on the axles. Between the inner plates is a bar connected to the diff carrier. This bar floats in a circular cut in each inner plate.

As power is applied, the bar is forced into the circular cuts and jams itself there. The pressure of the jam hold the teeth of the plates together. This is the locked position. So long as engine power is pressing that bar into place, the axles will turn as one.

Now, in a turn, the outer wheel wants to travel faster than the inner one. This causes the axle of that side to turn faster than the axle on the inside. The plates on that side then move away from the bar a little and contact the bar on the other side. Once the inner plate is held, the axle plate builds up enough tension to overcome the springs, and the two plates slide apart and the teeth are allowed to 'ratchet'. This ratchet effect is what allows turning and prevents major tire wear.

So, how does this help? Well, with no differential, the axles are connected as one, so both wheels push equally. This makes it easier to get traction, and even if one wheel is in the air, the other has full power to it.

Locker prices vary. The EZ Locker and the Lock-Right are DIY lockers that leave the factory diff carrier in place, and just change the guts. The average DIY can do the swap in about an hour. The stronger and more durable lockers like the Detroit require the replacement of the carrier and will need to be shimmed and measured as you do with a gear swap. If you are planning a gear swap, this is a good time to upgrade as the labor cost is ZERO to add the locker.

The easy lockers are in the $300+ range and the larger ones are $400+.

I prefer the Lock-Right as it is easy to install, and if you need to, you can back out the upgrade quickly and cheaply. If you are a rock hound and need the best, then the Detroit is the only choice.

Christopher Siano 0-       1B7KF23WxTJ

Date: Thu, 6 Mar 97 10:26:58 EST

Subject: RE: [RAM] lockers
> So, if you need to overhaul a 1500 (91/4" axle) would you better off to replace it with an after market limited slip differential? What's a good after market LS differential?

Glad you asked.

Why don't I list all the choices.

Chrysler 9.25":
LSD      -  factory, Auburn.
Locker  -  Lock-Right, spool

Dana 60:
LSD      -  Trac-Loc, TrueTrac, Powr-Lok,
Locker  -  Lock-Right, Detroit Locker, ARB Air Locker, spool

Dana 70:
LSD      -  Powr-Lok,
Locker  -  Lock-Right, Detroit Locker, ARB Air Locker, spool

Dana 80:
LSD      -  Powr-Lok,
Locker  -  Lock-Right, Detroit Locker, ARB Air Locker

OK, so what is what?  Here is a brief description:

LSD  (lImited Slip Diffs)

The factory Chrysler LSD is most likely a Trac-Loc design

the Trac-Loc is a 2 spider clutch pack operated LSD for light duty use.  Acceptable in a front axle application, and a major improvement over open differential in marginal traction situations.

The Auburn is the finest 3rd party LSD made.  With more pre-load and easy serviceability than the factory units, it is about the best you can do without going to a full locker.

The Powr-Loc is a 4 spider 2-piece unit that has about the same preload as the factory unit, but much easier to service, and significantly stronger in design.  It is possible that this the the unit used on the Dana 70/80 Hybrid axle behind the V-10 and Cummins.

the True-Trac is a different animal.  Instead of clutch packs, it uses gears to bind the differential.  Virtually wear proof, this unit keeps its full action across the life of the unit.  The true-trac is virtually an open diff while in normal use, but when one wheel wants to significantly travel faster than another, the forces inside the diff force the gears against the case and literally bind them in the process.  Ideal for front end applications, and where drivability is a must.
 > Been kinda curious about limited slips.  Anyone know much about  the Auburns?  I'm currently trying to find info on the net.

Some good info can be found at:

Look in the FAQ section, there is a locker, LSD FAQ.  The other FAQs are
also interesting, so look around.


One note about lockers: Lockers change the way a truck drives. Although it offers the most power directed to the ground of any unit above, a locker is not something for everyone. It is noisy in operation creating ratchet sounds in corners and loud 'BANG' when under load. Since the inside tire is the only driven one in turns, they create oversteer and alter the handling of the truck. Think carefully before selecting a locker. Read the descriptions for exceptions.

Lock-Right lockers use the factory case, and are easy to install. In operation, they are not the strongest locker, but offer minimal side effects in street operation and quieter lock/unlock operation. This is due to weaker springs and smaller teeth. Not designed for front axle use on the road.

Detroit Lockers are the big boys. These are strong and very powerful. When they lock and unlock, you know it. Maximum holding allows operation of a vehicle with wheels totally off the ground. Not designed for front axle use on the road.

ARB Air Lockers are a manual locker. You use a dash switch to lock and unlock. When unlocked, the truck handles like normal. When locked, both axle shafts turn at the same speed. The locked position is very good for traversing the worst terrain. However, being totally locked, there is more wear and tear on the tires, drivetrain, and other parts. Since this is a manual locker, you can choose when and where to use it. It is this ability that makes the ARB the best all around solution. ARBs can be used in the front axle, and when combined with a rear unit provides the highest amount of power transfer possible.

Spools are like ARBs always in the locked position.  They basically just make the axle shafts act like they are one shaft running from one wheel to the other.  Very abusive on the road as it causes tires to scuff as the truck turns.  Not designed for front axles.  Steering with a spool is very difficult as you must fight the tire's traction as well as the truck's momentum.  Cheapest solution of them all.

OK, so there is one locker that is cheaper than any of the above.  Called a Lincoln Locker, it is made by simply welding the side and spider gears of a normal differential to the case.  This effectively makes a DIY spool. Called the Lincoln Locker because the early welders used to do this were made by the Lincoln Welder Co.

Christopher Siano 0- |  1B7KF23WxTJ

Stan Steels Detroit Locker Comments

Subject:  [RAM] Detroit locker
Date:      Tue, 29 Jul 1997 08:46:10 -0400 (EDT)
From: (Stan Steele)

The front Dana 60 has had a Detroit locker for 3.55 it is # 225SL-29B . I am installing one in my truck in two weeks. If you want to get Tractech to make a Dana 80 3.55 [Detroit locker] call Bob Alex 1.800.328.3850 tell him Stan Steele said to call. We have been on their butts for 3 yrs. I had a productive conversation with Bob yesterday and the ball is rolling one more time!! If he gets calls from lots of people he can call for Production of the new 3.55 locker.


Joe Donnelly's Differential Comments

Subject:      [RAM] long post on setting diff gears
Date:          Sat, 17 May 1997 17:08:42 -0400 (EDT)
To:             RTML

Relevant section posted here:

   I have not been too happy with most limited slip units.  They seem to "lock up" just enough to cause chattering and tire wear, but not enough to help when you really need them.  If you can take some extra tire wear, and snapping and banging on corners if you abruptly apply/release power, the most famous, strongest, and most positive (while being user-friendly) "limited slip" carrier may be for you.  It is the No-Spin or Detroit Locker, from Tractech.  Since our Rams have long wheelbases, the positive locking and unlocking actions do not affect handling and steering nearly as much as on Jeeps and other short vehicles.  The Detroit Lockers are available for the 60 and 70 series.  They also have one for the 80, but they told me they really make it to supply it "OEM" to Ford for the Super Duty trucks.  For that reason, it is suitable only for 4.63 and 5.13 ratios.  They make one that will fit the Dodge with its 35 spline axles, but the ring gear mounting surface is about 3/16" too close to the pinion for the Dodge 3.54 and 4.10 ratio gearsets.  Tractech told me they plan to make one for Dodge ratios within a year.

     On snow, you may actually prefer an "open" differential, particularly on side slopes, because any limited slip can tend to make you slide downhill (sideways) as it locks, unlocks, and spins both tires.  The No-Spin is not recommended for the front differential of 4x4s, because it must unlock, or spin a tire, for you to turn.  This rough action strongly affects steering.  Also, if you are a hot-dog who greatly overloads the truck, you may be surprised how easy it is to BEND the axle tubes!  This is bad news (housings cost $$$) in any event, and even more so if you have a Detroit Locker, because the dog teeth inside the Locker will shear off if the axles are badly misaligned from a bent housing or from bent axles themselves.  These teeth then get into the pinion bearings.  Need I say more?


Last update September 19, 2002