Diff locks

Outback bloke · Post by **Outback bloke** » Sun Apr 29, 2007 6:03 am

I have been in touch with a few diff service people so far and have found one that says they can do it. Just got to get time to get this one down there to them so they can see it.

discopotato03 · Post by **discopotato03** » Sun Apr 29, 2007 11:22 am

I would think very long and hard before fitting a Detroit Locker/Tru Track/No spin centre to my "differential" .

Facts :

1) They ARE NOT a DIFFERENTIAL because they do not allow "differential action" which requires the normal bevel gears or Torson type centre .

2) A Detroit Locker has two sets of dove tailed dog clutches which transmit drive from the crown wheel to the axles when locked . They work by driving one or both axles - not necessarily both even when driving in a straight line . When you go round a corner the outside wheel side dog clutch will unlock and make a ratcheting click click click noise . Should you boot it or have to apply power ie uphill steep slow corner they lock up and drive like a solid axle (bad for tyres/suspension/body) . You find at times taking off from the lights one side locks and the car pulls in the direction of the locked clutch . When the other catches up and drops it it goes with an almighty crash noise - mine made people think I'd broken an axle and wondered why I could still drive away .
You also get strange things happen in circumstances like long high speed corners where your gently on and off the throttle . Old Detroit locks and onlocks either side randomely but the drive from one wheel then the other is a little unnerving .

I know these things because years ago I owned an FJ20 turbo powered Bluebird with a H190 Detroit locker in its butt , it was only done because plate type LSD's were poisonous to buy and it was the only affordable alternative at the time . Later it had a propper LSD and was much easier to live with .
Also while this locked axle business may sound grouse off road it does terrible things to your suspension and chassis . My Bluebird showed signs of stress in the body seams because of the unnatural forces being fed into it when Detroit was locked .
Your call but a Detroit Locker in the front of a front drive car would be suicidal . Be very scared of the fact that one positive wheel drive at the front in low gears/high torque loads is more than capable of ripping the steering wheel out of your hands with disasterous consequences - yes even with power steer . If anyone here has had time with rally Rexes they'll know that what works in the front is plate LSD's with very little pre load on the plates ie 12-20 lbs . This is done to combat steering loads and in fact understeer .
Nissan Works R190 Differentials . NOTHING in the way of R180 or R200 bits fits them and they are rocking horse do do . Don't bother .

Personally I think the only app for the "Boom Crash Opera" centre is in the back of a part time 4WD Subie . At least with no drive loads to it on the tarmac it shouldnt be very noticable - maybe . In a constant 4WD situation it will make the transmission wind up when its locked and the centre diff can't make allowances for it on hard surfaces . Understeer and tyre wear are the tell tales . Occasionally I drive Rural Fire Service Hinos and Isuzus with these centres fitted at the back and while they dont spin wheels they have lots of drive line backlash and are brutal on the suspension . Vehicles with lockable diffs are far more predictable and when not required the differential acts like a differential because thats what it is .

End rant and food for thought if you've never experienced a DL , cheers A .

Outback bloke · Post by **Outback bloke** » Sun Apr 29, 2007 7:30 pm

Points taken. Here is a few of my own thoughts. I have driven a lot of Subarus both on and offroad over the years with all manner of diffs in them. Open, LSD and CIG. Never with a locker but I have been 4wding with 2 Subaru drivers that have/had these diffs in their cars. One of these blokes has had his diff since they were first made in his turbo brumby. About 10 years to my knowledge and there is nothing wrong with his car. He has done thousands of k's in it since fitting it.

If you want to serious 4wd then locked of some description is the best. Open is **** and lsd is in between the two. The benefit this diff has it that it will open on the road all be it a little noisily at times. Far better than the welded diff I ran in my car for years.

There is no option for air lock with Subaru so you have to take what you can get. Simple as that.

A few things you said that I kinda disagree with.

I know these things because years ago I owned an FJ20 turbo powered Bluebird with a H190 Detroit locker in its butt , it was only done because plate type LSD's were poisonous to buy and it was the only affordable alternative at the time . Later it had a propper LSD and was much easier to live with .
Also while this locked axle business may sound grouse off road it does terrible things to your suspension and chassis . My Bluebird showed signs of stress in the body seams because of the unnatural forces being fed into it when Detroit was locked .

The fact that the Bluebird had a turbo charged motor driving that diff had nothing to do with the chassis probs at all? I think this would have put enough stress on the body with out the locker.

The 4wding that would be done with a diff of this nature in a Subaru would put less stress on the body and drive train than with out it. As you would know when you have traction obstacles are generally taken with a lot more ease than having to bang and bounce your way over them just to maintain momentum.

Personally I think the only app for the "Boom Crash Opera" centre is in the back of a part time 4WD Subie . At least with no drive loads to it on the tarmac it shouldnt be very noticable - maybe . In a constant 4WD situation it will make the transmission wind up when its locked and the centre diff can't make allowances for it on hard surfaces . Understeer and tyre wear are the tell tales .

This diff is going to play games a little in the back of any Subaru. Part time or full time 4wd, it is still going to need to unlock on corners, which it does. Both Mark and Scott never told me of any noise coming from it while driving. Neither has Dave (another club member with one in his ute) said any thing detrimental about this diff style.

In an AWD 4wd system it can not wind the centre diff up.

In a constant 4wd system you should not be driving with the centre diff locked on hard surfaces no matter what diff you have in the back.

Nor should you drive in 4wd in a 2wd/4wd box on hard surfaces. They will both bind badly and explode the gearbox case if driven like that for too long. This I know because I have swapped a lot of boxes for people that did not know this when they first got their Subaru.

Until some one invents an LSD that can lock at the push of a button we have to use what is best at the time. Put simply, this diff is the best you can get in this day and age for 4wding.

Jack · Post by **Jack** » Sun Apr 29, 2007 9:03 pm

Until some one invents an LSD that can lock at the push of a button .....

Detroit Electrac acts as a geared LSD then transforms into a cross axle diff lock at the push of a button. Not available for Subarus though.

http://www.jpmagazine.com/techarticles/ ... tion_lock/

Jack

discopotato03 · Post by **discopotato03** » Sun Apr 29, 2007 9:39 pm

Let me put it to you this way , when one side of a Detroit Locker locks , its axle drives a crownwheel speed (rpm) yes ? Yes . When an open centre differential goes around a courner the inner axle turns at lower rpm and the outer greater rpm than the crownwheel/hemisphere does . This is called differential action and Detroit Lockers can't do this . They do wind up all wheel drive transmissions (open centre diff) because they can't emulate differential action like the front diff can and so they fight each other . People with Range Rovers found this kind of thing out back in the 80's when they tried Detroit rear centres .

And for the record that Bluebird had the Detroit before the Turbo engine and then both and then the real LSD . The last combination was by far the best . The reason the body seams were stressed was because it was never intended to be used with a locked axle around corners .

Yes and been there with plate LSDs and played with preload and different spider ramp angles . IMO Torson centres offer the best all round compromise but they are not perfect .

One option not mentioned yet is a system called "Fiddle Brakes" . Its basically a hydraulic hand brake that when pushed one way brakes one side (rear) and when pushed the other brakes on the other side . Alternatively you could have a pair of hydraulic handles and use both if required . Food for thought from the dirt circuit side .

Cheers .

brumbyrunner · Post by **brumbyrunner** » Sun Apr 29, 2007 9:59 pm

discopotato03 wrote:I would think very long and hard before fitting a Detroit Locker/Tru Track/No spin centre to my "differential" .

Facts :

1) They ARE NOT a DIFFERENTIAL because they do not allow "differential action" which requires the normal bevel gears or Torson type centre .

Then what do you call the differential action provided when cornering with no load? ie when the detroit unlocks.

2) A Detroit Locker has two sets of dove tailed dog clutches which transmit drive from the crown wheel to the axles when locked . They work by driving one or both axles - not necessarily both even when driving in a straight line . When you go round a corner the outside wheel side dog clutch will unlock and make a ratcheting click click click noise . Should you boot it or have to apply power ie uphill steep slow corner they lock up and drive like a solid axle (bad for tyres/suspension/body) . You find at times taking off from the lights one side locks and the car pulls in the direction of the locked clutch . When the other catches up and drops it it goes with an almighty crash noise - mine made people think I'd broken an axle and wondered why I could still drive away .
You also get strange things happen in circumstances like long high speed corners where your gently on and off the throttle . Old Detroit locks and onlocks either side randomely but the drive from one wheel then the other is a little unnerving .

It is true that you will have to adjust your driving style if you choose to fit a detroit locker. You may also need to do this if you fit a lift kit, swap in an EJ20T, tow a trailer or drive in the snow etc.

Your call but a Detroit Locker in the front of a front drive car would be suicidal .

Where can you get a Detroit for the front diff of a Subie? I'll order one tomorrow.

Occasionally I drive Rural Fire Service Hinos and Isuzus with these centres fitted at the back and while they dont spin wheels they have lots of drive line backlash and are brutal on the suspension . Vehicles with lockable diffs are far more predictable and when not required the differential acts like a differential because thats what it is .

I drive a Landcruiser with a rear Detroit (and a Truetrack in the front diff) every day. I love it. It's not hard on the suspension, chassis or bodywork but it does give unbelievable traction all the time. No airlines, wires or cables to get ripped out, just works all the time and has never failed or broken.

BYB-01 wrote:
Put simply, this diff is the best you can get in this day and age for 4wding.

Exactly.

Jack wrote:Detroit Electrac acts as a geared LSD then transforms into a cross axle diff lock at the push of a button. Not available for Subarus though.
Jack

So?

Brumby Boy · Post by **Brumby Boy** » Sun Apr 29, 2007 11:30 pm

i have no real knowledge on how lockers(un-lockers) or spools (or the difference) work but after reading this thread i seem to have worked it out to some degree, both BYB and brumby runner make great points for the pros to the locker, and discopotato03 has brought up some points for cons but i'm still not entirely sold that they are a bad thing,
i know the land cruiser is a much tougher vehicle than the bluebird and is more suited to the locker but i'm sure the locker in each vehicle is there for a different purpose(ie "real" 4X4ing compared to rallying),

personally i know of a guy that had an AWD cruiser and he mostly did the sort of driving that our soobies do most of the time, and he had lockers in both diffs and never had a problem,

What i don't under stand how the locker in the rear of a sooby will bind a transmission unless it has a center LSD as it would allow for the difference in front to rear axle speeds, correct? if not why?

personally i will be using one of these as soon as they come out as i'm not overly keen on the reliability of a vlsd in a real off road situation although i have never used one.

Brett how long until these would be available? and are we still looking at around 1500 bucks?

cheers,
ian

brumbyrunner · Post by **brumbyrunner** » Mon Apr 30, 2007 6:29 am

A spool is a solid diff centre that permanantly locks both axles. Just like a welded diff. More for drag racing although some offroaders like them.

vincentvega · Post by **vincentvega** » Mon Apr 30, 2007 7:54 am

As scott is one of my best mates, I had access to this diff long before it was put up for sale. I thought long and hard about how it would work in my AWD lib and decided against buying it for the following reasons:

discopotato03 wrote:Let me put it to you this way , when one side of a Detroit Locker locks , its axle drives a crownwheel speed (rpm) yes ? Yes . When an open centre differential goes around a courner the inner axle turns at lower rpm and the outer greater rpm than the crownwheel/hemisphere does . This is called differential action and Detroit Lockers can't do this . They do wind up all wheel drive transmissions (open centre diff) because they can't emulate differential action like the front diff can and so they fight each other . People with Range Rovers found this kind of thing out back in the 80's when they tried Detroit rear centres .

I agree with this. this is my understanding of it.

going round a corner in an AWD car with power applied:

open front diff - inside wheel slows, outside wheel speeds up and the axle is able to turn the corner without binding.

detroit rear diff - inside wheel is locked to the pinion, outside wheel is also locked to the pinion as the diff is locked whenever driven. axle will bind through the corner

going round a corner in an AWD car with no power applied (coasting):

open front diff - inside wheel slows, outside wheel speeds up and the axle is able to turn the corner without binding.

detroit rear diff - inside wheel is locked to the pinion, outside wheel is allowed to speed up and unlock from the pinion (hence the nick name unlocker) and the axle can corner without binding (but makes a nice clock clock noise as it locks in and out

)

The problem here is that the front and rear axles are behaving differently, and therefore your front nad rear pinions spin at different speeds, causing your center diff to wear. In practice i dont know if this will be a problem as if you think about how often we all fly a front wheel and heat up the center diff and I dont know of anyone in a viscous center diff car that has burnt ut a center yet..

The only working option i see:

Run a Gen1 auto box and wire up the box so you can select between FWD and locked 4WD (easy to do) Then you can drive around in FWD on the road and have no issues with the locker locking onroad, and then hit 4WD and have the locker working perfectly as they have for years in the part time 4WD boxes.

The problem with this setup is teh center clutch packs that send power to the rear wheels in these boxes are weak as piss, and will slip, especially trying to push a locker. My car currently has selectable FWD / AWD / 4WD but the center clutches slip all the time driving an open rear diff, let alone a detroit locker.

I hope im wrong and the detroit can work happily behind an open center AWD system. This is my understanding of how it all works but im sure brett will convert scott's diff to 4.44 and put it in his lib soon enough. I cant wait to see what happens

Brumby Boy · Post by **Brumby Boy** » Mon Apr 30, 2007 10:01 am

vincentvega wrote: going round a corner in an AWD car with power applied:

open front diff - inside wheel slows, outside wheel speeds up and the axle is able to turn the corner without binding.

detroit rear diff - inside wheel is locked to the pinion, outside wheel is also locked to the pinion as the diff is locked whenever driven. axle will bind through the corner

going round a corner in an AWD car with no power applied (coasting):

open front diff - inside wheel slows, outside wheel speeds up and the axle is able to turn the corner without binding.

detroit rear diff - inside wheel is locked to the pinion, outside wheel is allowed to speed up and unlock from the pinion (hence the nick name unlocker) and the axle can corner without binding (but makes a nice clock clock noise as it locks in and out )

The problem here is that the front and rear axles are behaving differently, and therefore your front nad rear pinions spin at different speeds, causing your center diff to wear. In practice i dont know if this will be a problem as if you think about how often we all fly a front wheel and heat up the center diff and I dont know of anyone in a viscous center diff car that has burnt ut a center yet..

The only time i could see the box binding in an AWD would be if it had a Center LSD other wise the open center would allow for the difference in speeds, although i have a PT4x4 box so i don't have a problem.

Brumby Runner do you know the difference between a mini spool, half spool and a full spool??

Xtreme_RX · Post by **Xtreme_RX** » Mon Apr 30, 2007 10:38 am

I see no issue using one of these diff’s in Subarus on the rear - just don’t expect to throw the car in to a corner / roundabout & hope it will come out straight because you wont!

The 'unlockers' are a bit of a pig on the road to drive especially if you have a heavy right foot & love corners.....

YouTube · Post by **El_Freddo** » Mon Apr 30, 2007 10:56 am

brumbyrunner wrote:"Originally posted by El_Freddo:
In my mind, a rear diff locker wouldn't be harsh on the awd system unless your hammering the car to the point that the rear inside wheel starts to spin causing the outside wheel to lock (this is from what i've read from articles posted on this thread). And to do that as far as i'm concerned would be a pretty hard thing if your driving normally.

Correct me if i'm wrong."

You're wrong.

Fair go, i was putting it into how i see the thing work, its all new to me and i'm learning. Feels like it was shot down in flames

This debate is getting well heated. I think there are 3 groups here. Those that say "flat out no", those that say "hell yeah" and those that are still making up their mind. All of which are good to see for some healthy discussion.

What i'm wondering is: Will these lockers be available after the initial group buy? I'm still thinking about this and my cash flow would s**t itself at the thought of getting one of these asap.

I would also like to hear a "testiment" of someone who has no bias and drives a locker daily on road and takes it off road to see what they think about their application of this unit (someone who has just got the locker from an open rear diff). It would be good if we could get someone with an awd box and a pt box to do this (i'm looking at awd'n my L sometime soon).

Keep up the healthy discussion without shooting an inicent by-stander

Cheers

Brumby Boy · Post by **Brumby Boy** » Mon Apr 30, 2007 1:10 pm

Xtreme_RX wrote:I see no issue using one of these diff’s in Subarus on the rear - just don’t expect to throw the car in to a corner / roundabout & hope it will come out straight because you wont!

The 'unlockers' are a bit of a pig on the road to drive especially if you have a heavy right foot & love corners.....

Exactly as it was said before, having the locker will mean changing your driving style to suit,

It is true that you will have to adjust your driving style if you choose to fit a detroit locker. You may also need to do this if you fit a lift kit, swap in an EJ20T, tow a trailer or drive in the snow etc.

vincentvega · Post by **vincentvega** » Mon Apr 30, 2007 2:25 pm

head up freddo - everyones learning here. I am waiting to be shot to pieces myself

as far as getting a testament from someone with an AWD subaru and one of these diffs - there isnt anybody. Pretty much all of the 12 original diffs that were made are accounted for, and they all live in part time 4WD subies.

The diff brett just got his hands on will probably be the first to end up in an AWD car. Its going to be interesting to see what happens

Jack · Post by **Jack** » Mon Apr 30, 2007 2:42 pm

A cut and paste from the Locked Drive Systems (LDS) website .....

DETROIT LOCKER® MODELS
To Fit:
* Borg Warner 78 28 spline, 3.08
ratio (not IRS)
* Diahatsu Rocky Front or rear (not
IFS models)
* Ford 9" 28 spline
* Ford 9" 31 spline
* Jackeroo 17spl V6 front/4Cyl. rear
* Jeep AMC20, Dana 30, Dana 44
* Mazda B2600
* Ford Courier
* Nissan GQ Patrol front
* Landrover Defender
* Landrover Discovery (10 spline
axle)
* Ditto but 24 spline axle shaft
* Range Rovers as above
* Toyota Landcruiser LSD conversion
* Toyota L/Cruiser front & rear 40-75 series
to 1989
* Toyota L/Cruiser rear 75 series from 1990
and 80 series
* Constant 4WD
* Toyota L/Cruiser front 1990 on, 75 series
and 80 series
* Part time 4WD
* Toyota Hilux front & rear leaf spring open
diffs
* Toyota Hilux rear LSD models
* Toyota IFS 4 Runner rear

As you can see, Detroit lockers are available for both part-time and full-time 4WD systems. I can't see how an AWD Subaru system is too different from a Defender / Discovery / Range Rover / AWD LandCruiser and AWD Jeep systems.

http://locked-drive.com.au/product.htm

BlackMale · Post by **BlackMale** » Mon Apr 30, 2007 3:20 pm

At the risk of adding fuel to this thread *gulp*

Jack have a look at the pics and vids section and/or someone may be able to send you the link for the youtube thing that looked at just this… the difference between the AWD systems.

Do other members know what I am talking about or do I have to be more specific?

brumbyrunner · Post by **brumbyrunner** » Mon Apr 30, 2007 4:19 pm

Brumby Boy wrote:Brumby Runner do you know the difference between a mini spool, half spool and a full spool??

Is this a trick question?
No I don't.
I've never been interested enough to find out. Sounds like a savage thing to do to your diff.

El_Freddo wrote:Fair go, i was putting it into how i see the thing work, its all new to me and i'm learning. Feels like it was shot down in flames
This debate is getting well heated. I think there are 3 groups here. Those that say "flat out no", those that say "hell yeah" and those that are still making up their mind. All of which are good to see for some healthy discussion.
Keep up the healthy discussion without shooting an inicent by-stander

Sorry if you thought I was hard on you Freddo. You asked to be corrected if you were wrong. The operation of a detroit locker has been explained many times on this forum.
I guess I'm in the "hell yeah" group.

Fang · Post by **Fang** » Mon Apr 30, 2007 6:04 pm

Hmmm - While it may have been discussed previously - its affect on different drive systems has not. I have heard differing points of view from people on this board that I would consider very much "in the know". As vincentvega said none of these have been in Subaru AWDs yet - let alone some odd thing like my Full Time Box.

There is plenty of room on the forum to pose questions or give ideas. I'd rather know fully how it will affect my Full Time Box rather than a "she'll be right" approach.

Outback bloke · Post by **Outback bloke** » Mon Apr 30, 2007 6:22 pm

I like the way this topic is going. I didn't think any one was getting heated about it in any way. I do take notice of other peoples opinions even though I disagree with them, or some of them any way.

As VVega said, I will not hesitate to fit this diff to my AWD wagon as soon as I can. I would have it in there now if I didn't have to get it copied.

The AWD systems slip front to back all the time while you are driving. I can not see any way that this will make them slip any more or less. Maybe at different times, but no more or less.

YouTube · Post by **El_Freddo** » Mon Apr 30, 2007 6:54 pm

Jack wrote: As you can see, Detroit lockers are available for both part-time and full-time 4WD systems. I can't see how an AWD Subaru system is too different from a Defender / Discovery / Range Rover / AWD LandCruiser and AWD Jeep systems.

http://locked-drive.com.au/product.htm

The only difference i can see is that the subaru has independant suspension, meaning that we have CV joints as opposed to a solid axel from the diff centre to the wheel... this may be a problem, i don't know...

brumbyrunner wrote:I guess I'm in the "hell yeah" group

Hell yeah... what i was saying is that i didn't think ppl would be that up front with a "you were wrong", rather sort of bend it a little so to be a little gentle about it ]head up freddo - everyones learning here. I am waiting to be shot to pieces myself

as far as getting a testament from someone with an AWD subaru and one of these diffs - there isnt anybody. Pretty much all of the 12 original diffs that were made are accounted for, and they all live in part time 4WD subies.[/QUOTE]

Cheers VVega. The testiment i was asking about would be a future testiment as i know this was a good find and we're lucky to have this diff to be copied.

I guess we should all be thanking (sorry, can't remember who it was) for splitting the car and diff for this deal we've got.

Still want to know if these will be available after the initial purchase... or doesn't anyone know yet?

Cheers