Opinions On Drop In Diffs Using True-tracs Or Lockers??

[cockie55]

I would welcome some expert opinion and help with my drop-in replacement decision for factory front and rear diffs. This involves:

1. A minor moded auto V8 D1 Disco (24-spline) with minor suspension lift that I have owned since new so I know what it has done. Only drive train issues is some minor de-acceleration clunking associated with any multiple diff setup with 170K + under the belt.

2. I use this as my “daily driver” (low miles) plus I take I take it into some pretty hairy off road situations (traction issues particularly in sand when heavily loaded most of the time but only from time to time a lot of articulation) and usually alone and with no help around.

3. I aim to do a body lift and increase rubber to around 33” or so in the future.

4. The “daily driver” aspect makes me very cautious and respectful of extra strains caused by upgrading diffs so I don’t think I will putting axles, CV’s etc under threat…well at least intentionally.

5. Introducing additional noise and reduced on-road handling with this diff replacement exercise is not acceptable to me under any circumstances.

6. Additional switches, solenoids, relays, pressure switches, air compressor and air lines etc associated with on demand lockers does not worry me at all …but do I really need the added traction that comes with those complications and having regard for my use? See also Item #7.

7. Cost and interest wise I want to do this drop-in diff replacement myself…..I am pretty handy and have all the tools …but I am not a motor mechanic and I am “time poor” so other work like a disc to disc replacement etc etc becomes an issue.

With the above in mind I think my best bet subject to expert advice and opinion is an auto LSD set up and not fully blown lockers is as follows:

FRONT: Truetrac Front Differential. An auto gear-operated design like this is only option to preserve Disco constant 4Wd, seems to suit my off-road needs and with the potential straight-line tracking ability loss with in caster angle change in the front axle caused by a future lift; a Truetrac should do away with need to fit potentially inferior "caster-corrected" radius arms. Also as gear not plate type operated diff it requires no special oils, maintenance or operational expertise.

REAR: Likewise a Truetrac or possibly an auto locker like say a Detroit but I don’t think I need a locker with my use in mind and Truetrac will be easier on rest of my stock drive train plus I think easier to fit.

A. Is my drop-in replacements decision sound, (incl rear Truetrac instead of say an auto Detroit locker) and is the improvement worth the $ invested?

B. Am I realistic thinking I can install with little drama and can I do one (front then rear) at a time?

C. Should I be looking at replacing any other aspects of drive train, transfer etc etc while at it?

D. Should I be looking at changing gearing at the same time with future lift and rubber increase in mind or is this easy to do later?

Thanking you in anticipation.

[Blknight.aus]

now thats a well posed can of worms....

just for openers with all the other stuff your planning to do (Assuming your disco has a CDL )Id have thought that just a rear on demand locker would have pushed you through most of what you might come across and then you could fit another to the front later.... But theres a couple of little things you might be a tad off of the mark on...

changing the dffs (unless you also change ratios) doesnt really put any more strain on any other component than a normal rover diff does and unless youve got a bung diff wont add anymore noise, that usually comes from your choice of rubber.

the castor correction isnt a problem for changing the diff (unless Im off the mark on what your calling a true track diff a true track is just a diff that is desinged as an lsd/lock diff for a front axle) its from lifting it, as you lift it the front axle pivots down on its locating arms and this in turn changes the castor (and kingpin inclination angles+ toe in on turn adustments) which is what you need to correct. all of which now requires inspections to pass for roadworthy and its getting harder to get that stuff past.

hope thats helpful in some way.

[cockie55]

Dave thanks ...but probably a bucket not a can of worms with the length of my post...

Yes I have CDL... however you will see my severe off road driving conditions being heavy load in loose stuff being sand and gravel etc I am inclined to think getting all 4 X wheels getting traction albeit reduced <100% is preferable to on-demand 100% rear lock only as being the best option for me??? Then again if I knew why would I ask one would say???

If I am contemplating drop in F&R diff changes to get traction happening on both front and rear wheels (not one of each under CDL), I hope to buggery they are putting more strain on my stock drive train (strengthening the diff and it's torque transfer = axles and CV's etc higher stress loads = increased wheel traction)....otherwise why bother changing diffs?...and yes as I indicate I am contemplating a lower gear change with extra rubber diameter to add to that strain on stock axles and CV's etc.

My comments about the castor correction were not directed at emanating from changing the front diff but from a lift, but then a truetrac style front LSD solves any castor correction issues associated with that lift as I am led to believe? Then again if I knew why would i ask?

Thanks Dave

[Tusker]

Your #5 prerequisite rules out a Detroit locker, they can be clunky on road, and make the handly a bit squirrely in SWB cars. A mate in LROC had an early Disco with a Detroit, didn't tell SWMBO, but she picked something was "wrong" with the car.

If you've had a poke around expeditionexchange.com, you'll see the Yanks favour a front truetrac to overcome the castor loss. Seems to me you'd be better curing the disease, not masking the symptoms.

Have you got traction control? If so go Truetracs F&R. They work well together.

But the ultimate is conventional lockers. Completely undisturbed handling on-road, & heaps more traction off-road - but only when you need it.

Regards
Max P

[cockie55]

Thanks Max.

I will be not going very high or beyond 32/33 tyres so I am hoping castor loss not a real issue and little there is that a front truetrac would deal with it.

A D1 so it has no traction control. The clunkyness of the Detroit is a pity to hear as I thought it a good auto locker for Discos and a half way choice with my typical conditions in mind maybe not warranting a 100% on demand locker. Instal at diff also appears easy compared to a on demand locker was also making it attractive.

Putting auto and on demand locker aside my main concern with Truetracs front and rear is do they really deliver much extra traction in sand/gravely conditions???

[BigJon]

Putting auto and on demand locker aside my main concern with Truetracs front and rear is do they really deliver much extra traction in sand/gravely conditions???

I have a rear TrueTrac in my 88 Rangie. The difference it made on sand is astounding. Rather than dig holes by spinning diagonally opposite wheels and getting stuck, it just keeps driving forwards. Very soft sand at road pressures will see it sink in until the rims are touching the sand, but it still moves forwards (slowly).
As an added bonus, stopping one rear wheel from spinning freely also prevents one front wheel from spinning.

[Chucaro]

I have a rear TrueTrac in my 88 Rangie. The difference it made on sand is astounding. Rather than dig holes by spinning diagonally opposite wheels and getting stuck, it just keeps driving forwards. Very soft sand at road pressures will see it sink in until the rims are touching the sand, but it still moves forwards (slowly).
As an added bonus, stopping one rear wheel from spinning freely also prevents one front wheel from spinning.

BigJon do you know who is the agent for TruTrac in Oz ?
Cheers

[jbell110]

Opposite Lock stock true-trac & detroit there good to deal with

Jeff

[Chucaro]

Thanks mate

[BigJon]

BigJon do you know who is the agent for TruTrac in Oz ?
Cheers

I got mine from LDS (Locked Drive Systems).

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