traction enhancement

[siii8873]

I'm considering upgrading my rear diff with a limited slip or locker of some sort. Right now I am leaning toward a detriot locker or tru trac.
I would like to know everyones opinion on their experience with either of these, good / bad, on/off road.
Thanks
Bob

[Firemanshort]

Bob -

Look here.... http://www.maritimerovers.org/smf/index.php?topic=2689.0

Video and discussion with vendor identified.

[I Leak Oil]

Either unit is good but both will give you different handling characteristics. The pros and cons have been debated to death on the 'net. Either one will be a nice upgrade over the stock rover POS carrier. Of the two, I'd go with the tru-trac if you're not upgrading the shafts or don't do much trail riding.
Disclaimer. See your mechanic for enhanced traction devices lasting more than 4 hours!:D

[TeriAnn]

Going to either a trutrac or a detroit locker is going to put additional stress on those already pathetically weak 10 spline axles.

I'd suggest you take the opportunity to get a set of 24 spline rear axles & the 24 spline version of whichever carrier you choose.

[RoverForm]

http://www.maritimerovers.org/smf/index.php?topic=2689.0

i don't know what it is, but i'm really into:

a) those tires
b) the sound of that 300Di

[LR Max]

I've got a Detroit locker in the rear of my 109. All I can say is its COMPLETELY AWESOME.

Off road, there is no substitute (well, I guess an ARB or welded diff can be a substitute but same idea) for a full locker. It just works and the capabilities of the truck will be transformed.

On road I noticed a difference when I first installed, but now I'm used to it. Every once in a while (like, every other month) it'll pop. All it does is make a loud sound, nothing else. In comparison, I've seen the unlocking throw a jeep over into another lane.

You'll be satisfied with the detroit. It'll perform amazingly well and you might as well go all the way if you are gonna tear apart your rear axle.

X2 on the 24 spline or do a Salisbury swap. The Salisbury swap might be cheaper considering a Salisbury Detroit is cheaper than a rover style Detroit (and you don't have to replace the carrier, no gear reset, and no need to convert to 24 spline because it already has it!!). Beefy ring gear, the works.

And yes, I've broken 2 axle shafts in my Salisbury. Except for the axles, no other damage was incurred.

[TedW]

Isn't a Detroit locker and a trutrac the same thing? If not, what's the difference?

Which would be better for someone (that would be me) who plans to install a Salisbury rear and who does most of his driving in snow and on road, with occasional off-road forays?

Is it worth the expense to install a front one as well?

Thanks - Ted

[LaneRover]

Isn't a Detroit locker and a trutrac the same thing? If not, what's the difference?

Which would be better for someone (that would be me) who plans to install a Salisbury rear and who does most of his driving in snow and on road, with occasional off-road forays?

Is it worth the expense to install a front one as well?

Thanks - Ted

IMHO with the occasional off-roading and snow I think it would not be worth the expense of putting one in the front axle. I do not have the experience with them to tell you which would be better in the Salisbury axle.

[AU_88]

I may be a little off, but a detroit is a locking diff, and I believe it's locked all the time, so when you drive on-road your rear tires will chirp. The tru-trac is a limited slip diff, and basically aids with traction as necessary but isn't locked and will be better on road. I have ARB air lockers on my discovery which can be turned on an off, they are more expensive, but really nice. Hopefully someone else can give you a better explanation.

[yorker]

Yeah a Detroit Locker is a locker. A "Detroit" Truetrac is a limited slip that does NOT use clutches like more common limited slips but uses helical gears kind of like a Gleason Torsen differential does.
http://www.torsen.com/files/Traction_Control_Article.pdf
http://www.offroaders.com/reviewbox/showproduct.php?product=252

If you are into more ******** 2 wheels in the air type offroading a ARB or Detroit Locker or the Toyota E locker swap would be worth looking into. I honestly think the Truetrac makes more sense for most people with Series Rovers.

[mongoswede]

a popular combination is to run a true locking diff in the rear (air or electric)...so when its locked its like having a solid axle and when its not its open and freewheels like stock. Then run a limited slip in the front. The crazy offroad rigs usually run lockers in the front, rear, and in the transfer case if its not already built in...or they swap in a lockable transfer case.

Just keep in mind that limited slips and lockers will put a lot more strain on the rest of your drive train...so make sure your axles, Ring and Pinion, diff carrier, carrier bearings etc are all in good condition...probably be a good idea to carry a few spare axles shafts and magnet to help remove broken bits.

[siii8873]

I do not understand the need for a transfer case locker, what does that change? is there a slip between front and rear wheels with standard transefer box.

[KevinNY]

Your series transfer case is always locked when in 4wd. Vehicles like a Discovery are permanent 4wd and need the ability to slip the center diff for dry pavement use but can lock it for off highway use.

[NickDawson]

forgive the hijack - have also been eyeing the truetracks and have recently developed some slop in the rear diff that makes me worried it is on the way out.

As I understand it, series IIIs have salisbury axles, complete with 24 splines, right? Does that mean I'd order a salisbury locker? Trying to figure out which model...

[Cutter]

I think only on the 109s

[JimCT]

I installed a Detroit locker in the Salisbury rear axle of our ambulance and it is the best mod I have done to the beast. No quirks on the road, just a rare pop when it releases. Also have GB Aussie upgraded axles and axle drive flange after breaking a Salisbury axle. Bullet proof so far, and we are not that easy on the ambulance.

[AU_88]

I do not understand the need for a transfer case locker, what does that change? is there a slip between front and rear wheels with standard transefer box.

An open transfer case is like an open diff, an open diff will allow most of the power to go to the wheel with the least amount of resistance, a locker will send the same amount of power to each wheel no matter the resistance, the same is true for the transfer case, if one axle has less resistance, most of the power will go to that axle, but with a locked TC it sends relatively equal power to both axles.

[TeriAnn]

An open transfer case is like an open diff, an open diff will allow most of the power to go to the wheel with the least amount of resistance, a locker will send the same amount of power to each wheel no matter the resistance, the same is true for the transfer case, if one axle has less resistance, most of the power will go to that axle, but with a locked TC it sends relatively equal power to both axles.

Time for a comment or three:

1. The full time 4WD Rovers have transfer case that is like a center differential that can vary the power sent to the front and rear depending upon need. These transfercases need to be locked to provide equal power front and back. The series transfercase is part time 4WD. When it is in 4WD it is always locked, providing equal power to the front and rear.

2. A Detroit locker is an automatic locking diff and applies equal power to both axles when it is locked and works like an open diff when it is not locked.

Personally I don't like the Detroit locker because I would have no control of when it decides to lock and when it decides to unlock. I much prefer a manual locker so I decide when I want to to challenge an obstical with an open diff or want to get serious with a locked diff. I have an ARB in the rear. My personal preference.

2. The Salisbury is a Dana 60 made under license in the UK. It has a beefier carrier and ring and pinion gears and is 24 spline. Detroit carriers designed for the old style Dana 60 fit. The Salisbury was standard fitment on the rear of SIII 109s only. It is a bolt on swap with the earlier 109s. You just need to uses the stock SIII 109 rear propshaft. The Salisbury requires moving the spring perches inboard and for the already short rear propshaft to be shortened even more if you try to fit one to an 88. An 88 is better off keeping the Rover axle housing and converting the guts to 24 spline.

A Salisbury front diff was standard fitment to the SIII One Ton model and can be moved over to the 109 as well but they are hard to come by.

3. A Detroit Trutrac is a limited slip carrier that never truly locks. As long as both tyres have some traction the trutrac will send power to both axles. If one axle is in the air or on slick ice where there is no traction it acts like an open diff and there is no power to either axle. Like an open diff the Trutrac needs resistance on both axles to work. The way to cheat is to lightly ride the brakes to simulate traction on both axles when one tyre is in the air.

4. Lockers on the front axle are superior to limited slips as long as you are driving in a straight line. However, try to work the tyres for increased traction on the tyre edges or turn and you put a lot of stress on the front axles. A limited slip lets you work the tyres and turn the wheel as you climb or descend without nearly as much axle stress. Which is why most people go for a limited slip on the front and a locker on the rear. The stock Rover carrier is a week 2 pin design and you are MUCH better off with any of the aftermarket or the Salisbury carrier.

5. The Rover 4.7:1 R&P gears are thin and not known for its strength. When used with any of the lockers you need to use a spacer with it to make the combination thicker. The Salisbury 4.7:1 is a beefy gear set. There is an aftermarket 4.75:1 R&P that is as thick as the Salisbury R&P and has a lot of meat on the gears making it a lot stronger than the Rover R&P. It is a recommended R&P upgrade when going to a limited slip or locker in a Rover diff.


http://www.expeditionlandrover.info/GRdetailPics/Frontdiffs.jpg
4.75 Ring gear on left mounted to a TruTrac carrier.
Rover 4.7:1 ring gear sitting on a spacer plate on right mounted to a Quaife limited slip carrier.

While I'm at it:
http://www.expeditionlandrover.info/GRdetailPics/frontAxleEnd2.jpg
24 spline axles net to a 10 spline axle

http://www.expeditionlandrover.info/GRdetailPics/frontAxleInner.jpg

Below 24 spline front axle vs 10 spline front axle:


http://www.expeditionlandrover.info/GRdetailPics/frontouterAxles.jpg
http://www.expeditionlandrover.info/GRdetailPics/frontouterAxles.jpg



I any one is interested, my 109 has a Ford 5.0L V8, NP435 close ratio gearbox, Series transfercase with Ashcroft high ratio kit, rear Salisbury with ARB, and hardened Great Basin rear axles. The front is a 24 spline Trutrac, 4.75 R&P and Seriestrac 24 spline front axles. It has been a trouble free combination for me that I'm real happy with. The combination gives me 50:1 low range first at the axle (stock LR is 40:1) and with 33 inch dia tyres 65MPH is at 2650 RPM.

[JimCT]

I had intended to install an ARB locker in our ambulance, but the one time we laid it over on it's side I could have driven out of the situation if i had a locker, but i would never have had time to engage the ARB. It was a side hill and as soon as both high side wheels left the ground I lost forward motion, if I had the Detroit I could have driven it down the grade abit and saved it. And I have to say at least in the ambulance the Detroit locker is a joy. just something else to think about.

[AU_88]

I had intended to install an ARB locker in our ambulance, but the one time we laid it over on it's side I could have driven out of the situation if i had a locker, but i would never have had time to engage the ARB. It was a side hill and as soon as both high side wheels left the ground I lost forward motion, if I had the Detroit I could have driven it down the grade abit and saved it. And I have to say at least in the ambulance the Detroit locker is a joy. just something else to think about.

I generally turn on my rear locker when I see something that may give me trouble. If I cant get past it with the rear locked, then I reach up and flip the front switch.... No biggy.

[lrdukdog]

This seems to be a "to each their own" as to which is better.
Jim Wolf

[AU_88]

This seems to be a "to each their own" as to which is better.
Jim Wolf

Agreed.

[TedW]

I lean towards taking TerriAnn's advice and switching my rear end to 24-spline, and adding a truetrac. However, I also lean towards leaving the front end as is (10-spline).

[mongoswede]

a general way to think about this is: a locker will only be activated when you engage it. So you only use it when needed. A limited slip will be working all the time whether you want it to or not. It takes a little getting used to the feel of a limited slip in your drive train.

[I Leak Oil]

a general way to think about this is: a locker will only be activated when you engage it. So you only use it when needed. A limited slip will be working all the time whether you want it to or not. It takes a little getting used to the feel of a limited slip in your drive train.

Depends on which locking Diff you get....

[NickDawson]

I liked the idea of replacing my stock diff with a truetrack until I looked at the cost of moving to 24 splines* - not sure I do enough off roading to justify it...

How risky are they with 10 spline axels? Is it a guaranteed matter of time before they snap?

*also need to check my frankenrover as it may likely have a 109 rear and/or 24 spline axels - any quick way to check?

[mongoswede]

Depends on which locking Diff you get....


I guess when I think of lockers I think of air or electric engagement that are pretty much on off. Everything else I consider a limited slip.

[I Leak Oil]

I guess when I think of lockers I think of air or electric engagement that are pretty much on off. Everything else I consider a limited slip.

So you consider a detroit locking diff a limited slip because of it's lack of driver control? What about a spool? No switches there. A detroit is every bit a viable locking diff as an ARB or an e-locker. Just not selectable. Do you have any personal experience with a detroit? I do. I currently have ARB's but that's for my own reasons, not because a detroit is any less effective, just different. It's certainly not a limited slip....

[I Leak Oil]

I liked the idea of replacing my stock diff with a truetrack until I looked at the cost of moving to 24 splines* - not sure I do enough off roading to justify it...

How risky are they with 10 spline axels? Is it a guaranteed matter of time before they snap?

*also need to check my frankenrover as it may likely have a 109 rear and/or 24 spline axels - any quick way to check?

10 splines are guaranteed to snap with a stock carrier nevermind a ltd slip or locking diff. To check your spline count....pull the axle shaft. 6 bolts is all it takes.

[JimCT]

Not sure where you are getting your info but there is no slip in the Detroit Locker. It works great.

[mongoswede]

So you consider a detroit locking diff a limited slip because of it's lack of driver control? What about a spool? No switches there. A detroit is every bit a viable locking diff as an ARB or an e-locker. Just not selectable. Do you have any personal experience with a detroit? I do. I currently have ARB's but that's for my own reasons, not because a detroit is any less effective, just different. It's certainly not a limited slip....


easy tiger. I didn't mean this to turn into a wack each other on the head thread. I don't have any experience with the detroit locker. Perhaps what I should have written was that there are limited slips, autolockers, and selectable lockers. Where in my mind...maybe only my mind I tend to think of the electric and air selectable units as lockers. Everthing else I think of as a limited slip (right or wrong). I have a clutch type limited slip diff for my Saab and it locks up completely when either wheel starts to slip....while it can slip and definitely stays locked when you are hard on the throttle and only releases if you back off the throttle.
Spools are just locked all the time and I wouldn't call a locker or a limited slip...they are just a convienient way to lock your axle without installing a completely solid axle.

[bkreutz]

Easiest way to understand how a Detroit Locker works is to think of a ratchet, under power they lock up, when in a coast condition the slower axle ratchets. (that's why hot rods make a clicking noise from the rear when going around a corner). Spools aren't very good for street applications (unless you like sliding one tire through a corner:D)

[I Leak Oil]

easy tiger. I didn't mean this to turn into a wack each other on the head thread. I don't have any experience with the detroit locker.

Tiger???? Wow, that's the first time anyone's called me that. Give me a moment so I can put on my kid gloves here first.....





OK I'm back...
I'm hardly wacking you over the head here. Perhaps just questioning your position on considering any unit that isn't air or electrically actuated to be a limited slip. It's OK to question and disagree here isn't it?

I'd hate to see someone go spend a lot of money on a detroit thinking they're getting a less aggressive limited slip, only to find out it's a full blown locking diff with all it's quirks and broken half shafts. I know I'd be pissed!

[mongoswede]

Tiger???? Wow, that's the first time anyone's called me that. Give me a moment so I can put on my kid gloves here first.....


OK I'm back...
I'm hardly wacking you over the head here. Perhaps just questioning your position on considering any unit that isn't air or electrically actuated to be a limited slip. It's OK to question and disagree here isn't it? yes

I'd hate to see someone go spend a lot of money on a detroit thinking they're getting a less aggressive limited slip, only to find out it's a full blown locking diff with all it's quirks and broken half shafts. I know I'd be pissed!

its the oldest internet problem in the book....impossible to read tone and inflection into what is written. What I write and you read and vice versa will more than likely be entirely misunderstood from an emotion kind of view. :thumb-up:


My thoughts are that the detroit locks up but has the ability to unlock and allow for different wheel spin when not under power. The selectable lockers remain locked (please correct me if I am wrong). Thats why I guess I think of the autolockers in the limited slip category....because they can unlock where a unit like the ARB air locker remains locked as long as its switched on. While they are not technically limited slip as they are 100% locked when they go into lock mode but can unlock. make any sense?

[I Leak Oil]

I understand how they work but I don't understand how they can be considered limited slips. They are traction aids. They help gain traction when power is applied. A limited slip allows the diff to slip to varying degrees under load. A locking diff does not. It's how it works under load (trying to gain traction) that matters.

[LR Max]

Detroit lockers have driver control!

Foot off gas pedal = it will unlock.

Foot on gas pedal = it will lock

Full steering wheel lock, rolling 2nd gear clutch sidestep + full gas pedal = BEING AWESOME :thumb-up:

Better than an ARB because all said controls are already on the truck.

[mongoswede]

I understand how they work but I don't understand how they can be considered limited slips. They are traction aids. They help gain traction when power is applied. A limited slip allows the diff to slip to varying degrees under load. A locking diff does not. It's how it works under load (trying to gain traction) that matters.


I'm sorry...I didn't express myself properly. I was trying to say that I think of them in the same category as limited slips even though they are not. I can see that this is a waste of words...My brain is clearly in its own swamp so feel free to point at the ogre and say he's confused and we can move forwards :D

[siii8873]

WOW, opened up a can of worms here. Thanks everyone for the information. From my perspective, no experience with any type, this discussion has been great. I wanted to hear opinions and that I did.
To each his own no right or wrong.
Thanks

[I Leak Oil]

To each his own no right or wrong.


That's exactly it. It's YOUR truck. Do your research and decide which unit with it's +'s and -'s is best for you. Don't listen to the brand "X" is best arguements. Rarely is there a one size fits all product. Best of luck with what ever you choose.

[Tim Smith]

I can tell you that I have a truetrac in the rear with the 24 spline upgraded half shafts. Front is stock rover with 10 spline. I absolutely love the set up. I helps through the sticky spots when it can but mainly I just love the fact that I don't have to worry about half shafts any more.

Whichever you decide on, remember that a locker/limited slip device should not be used to compensate for driver skill. If you go about your off roading that way, you'll end up spending way more money than you need to and some ninny like me will still run circles around you. :p

Bill at Great Basin Rovers is a great source of information on third members.

[junkyddog11]

With Series Rover axles I wouldn't consider anything other than a selectable locker (ARB ....Detroits are not selectable if you actually want to move). You can upgrade the axle shafts but the R&P will not stand the constant abuse of a Detriot for long. Even the limited slip can be a bit much. Of course this does not apply to the Salisbury version.

[lrdukdog]

I know several fisherman that do beach surf fishing that use the Detroit set-up (lockers rear and limited slip front) and swear by it. As in "never get stuck" in soft sand etc.
Jim Wolf

[TJR]

Yes ARB's cost a bit more. but I chose to put one the rear of my relativley short wheelbase early bronco figuring if it save me one accident from spinning out on a slippery road, it was worth the extra price.
I also though my wife would drive the truck too.. but that never happened. That was 10 years ago.. The ARB has been fine e.g. o-rings etc, but other parts of the truck have not help up so well...i.e rust

I'd get a ARB again (24 spline) for my 88 if it were in the budget.

...Talbot

[junkyddog11]

I know several fisherman that do beach surf fishing that use the Detroit set-up (lockers rear and limited slip front) and swear by it. As in "never get stuck" in soft sand etc.
Jim Wolf

No doubt we all know people who use them and have no issues. The Detroit / tru trac combi is the "old standby" I'd guess and it certainly is *dependable* especially in soft sand. History is that they do wear the rest of the drivetrain which is imo worth considering.
I probably was a little over the deep end when I suggested not even considering the Detroit . I'd suppose that it may come down to a budget decision in many cases.