Diff Education Needed.

[IJ.]

Dana were/are the manufacturer, and PowrLok was the brand-name given to the unit which was supplied to many manufacturers as an OE fitment - Jag, Volvo, Willys, GM etc. Dana are/were very big in the US as a specialist drive-line components manufacturer and also made the unit fitted to the Holden CrossTrak which is also the same unit supplied to BMW for their X5. @IJ - there might be some other components there that may be of use to you...

Nah it was New Venture/ New Process that made the Transfer cases Seldo, just upgraded mine to a Torsen T3 unit so frying front tyres is a thing of the past

[offshore]

One other thing I notice with the true track is it introduces a bit of torque vectoring you can see it in low speed corners or say a round about you get on the throttle a bit in the middle of the bend and because of weight transfer there is more torque going to the outside wheel with more traction and it tucks the front in slightly.

[IJ.]

One other thing I notice with the true track is it introduces a bit of torque vectoring you can see it in low speed corners or say a round about you get on the throttle a bit in the middle of the bend and because of weight transfer there is more torque going to the outside wheel with more traction and it tucks the front in slightly.

I love the fact they don't have the part throttle understeer of a tight enough to work conventional LSD

[offshore]

I love the fact they don't have the part throttle understeer of a tight enough to work conventional LSD

Yea exactly

[feistl]

Big thread dig i know, but just thought id share my opinion on LSD vs Trutrac...

I have a Manual VX (450rwkw) with a Harrop Trutrac and 3.91 gears.
I also have a Manual VY which had a Eaton Trutrac with 3.91 gears, but was recently swapped to a new LSD (still 3.91 gears).
I also just got an Auto VZ which has a tight LSD in standard 3.08 gears.

Now having driven all 3 of them in the last week (including the trutrac to LSD swap in the VY) i have noticed some subtle differences.

I should point out that there are obviously a lot of variables so this isnt fact, just my observations...

Firstly, Eaton vs Harrop trutrac...

• Only noticeable difference was the eaton tended to have a little more "slop" or "give". As in there is a slight "clunk" when getting on/off power (Tailshaft has new donuts, driveshafts have no slop in CVs, all new suspension and bushes so the rest is tight). This wasn't as noticeable with the Harrop Unit. I also noticed the slop when physically playing with the input/output of the diffs by hand (before they were installed).

LSD vs trutrac

• Pretty much in ever regard the trutrac is superior.
• The LSDs tend to make the back feel spongy. EG, With a LSD when accelerating hard around a corner it feels like the inside wheel is getting more drive, causing the rear to move sideways and squirm a bit. Not a great feeling. The trutrac on the otherhand seems to drive both wheels more equally, which tends to pull the car into a straight line. Makes it feel a lot more planted, even under light load.
• The only advantage to a LSD is it seems to be a little smoother in power delivery. This is most noticeable in the wet... The trutrac tends to be very sudden with its engagement which causes the rear wheels to break traction, whereas the LSD seemed to be a little smoother giving the tyre sidewall a chance to deform slightly and maintain grip. I know that seems counter intuitive, but having just got back from a drive in heavy rain and doing some pretty quick starts i was surprised at how well the LSD got the (relatively small amount) of power to the road.

Having just swapped from a trutrac to new LSD (with no other changes) gave real world "Back to back" feedback.

For big power (350rwkw+) id say go the Harrop, for anything less go the eaton.

Also, avoid the Trutrac diffs on ebay (Circa $1500). It took the diff "builder" 4 attempted to get mine working properly (With me having to pull/install the diff each time).

Spend a little more and get a quality workshop to install.

Cheers, Errol

[Camos]

Yes agree.

I tossed the standard LSD in my hilux for an Eaton Truetrac.
It's the best all round diff I have driven. Not as good as a locked diff off road but you don't have to engage and disengage all the time, the traction is always there so my vote is also for the trutrac.
It handles so much different now, especially since it now has 285kw punching through those gears. Sooo much fun that my cheeks hurt from grinning all the time.

I am running 4.3:1 which was standard and have 31in rubber. I am thinking of going a 4.7 to take a bit of load off the engine since the new rubber is quite a bit bigger than the commodores but that's a story for another day

[Red CV8 R]

Having just swapped from a trutrac to new LSD (with no other changes) gave real world "Back to back" feedback.

For big power (350rwkw+) id say go the Harrop, for anything less go the eaton.

Also, avoid the Trutrac diffs on ebay (Circa $1500). It took the diff "builder" 4 attempted to get mine working properly (With me having to pull/install the diff each time).

Spend a little more and get a quality workshop to install.

Cheers, Errol

Excellent post, thank you for sharing your experiences Errol.

Does anyone know if Harrop still sell their version of a Truetrac? I see they still have the standard Eaton version for $1,099.01 listed on their website plus a full made to order diff using their unit for $5,500.00 but no longer have the stand alone version listed that I can see?

[white lie]

Excellent post, thank you for sharing your experiences Errol.

Does anyone know if Harrop still sell their version of a Truetrac? I see they still have the standard Eaton version for $1,099.01 listed on their website plus a full made to order diff using their unit for $5,500.00 but no longer have the stand alone version listed that I can see?

That is the Harrop version...they're all made by Eaton (much like supercharger rotors), this is just to Harrop specs so its a Harrop Eaton. The lower rated one is just Eaton alone and won't have the Harrop logo stamped on it.
The regular Eaton is a fair bit cheaper, Tuff Car Parts and the like sell it locally for about $750-800, not sure what deal you'd get overseas at the current exchange but for 1100 its a pretty good deal IMO. Cheaper than they used to be.

[macca_779]

That is the Harrop version...they're all made by Eaton (much like supercharger rotors), this is just to Harrop specs so its a Harrop Eaton. The lower rated one is just Eaton alone and won't have the Harrop logo stamped on it.
The regular Eaton is a fair bit cheaper, Tuff Car Parts and the like sell it locally for about $750-800, not sure what deal you'd get overseas at the current exchange but for 1100 its a pretty good deal IMO. Cheaper than they used to be.

I was under the impression Harrop manufactured their own gear sets in house based on the Eaton design

[white lie]

You may be right there...for some reason I thought they were all done by Eaton

[SASLS1]

From Harrop FB page.


" Harrop Eaton Truetrac Facts

After 60 years of manufacturing quality products, we understand what it takes to produce a performance product that surpasses expectations. When it comes to driveline components for your vehicle, there is no room for inferior quality parts, so insist on the best.

All of our Harrop Eaton Truetracs are manufactured in Melbourne to the highest standards and have undergone extensive testing, from finite element analysis in the design stage through to lab durability testing and powering thousands of our beloved Holdens and Fords down the strip, and across our great country.

When purchasing your next Truetrac differential make sure to ask if it is a Harrop Eaton unit and look for these key signs to verify you are getting what you paid for; All Harrop Eaton differentials carry a unique serial number etched into the outer circumference of the Crown wheel mating flange, they will have both the Harrop and Eaton logo machined into the outer face of the casing along with the part number. If you find all of these elements you are good to go."

​
Some dodgy places are selling fake Eaton Truetrac's too, which are cheap chinese rubbish to watch out for...

Best way is to call them up direct.

[Red CV8 R]

That is the Harrop version...they're all made by Eaton (much like supercharger rotors), this is just to Harrop specs so its a Harrop Eaton. The lower rated one is just Eaton alone and won't have the Harrop logo stamped on it.
The regular Eaton is a fair bit cheaper, Tuff Car Parts and the like sell it locally for about $750-800, not sure what deal you'd get overseas at the current exchange but for 1100 its a pretty good deal IMO. Cheaper than they used to be.

As stated by other posters Harrop made their own version based on the Eaton. The link for the only M80 28 spline Eaton on their website ( https://www.harrop.com.au/shop/autom...8-spline-eaton ) says down the bottom:

Note:

This part is the standard Eaton Detroit Truetrac part not the locally made Harrop/Eaton equivalent.

I'm sure they previously had their version on the website but I can't see it there now so they may not make that product any longer, perhaps other than made to order? I think the Harrop version was around $1500?

[white lie]

As stated by other posters Harrop made their own version based on the Eaton. The link for the only M80 28 spline Eaton on their website ( https://www.harrop.com.au/shop/autom...8-spline-eaton ) says down the bottom:

Note:

This part is the standard Eaton Detroit Truetrac part not the locally made Harrop/Eaton equivalent.

I'm sure they previously had their version on the website but I can't see it there now so they may not make that product any longer, perhaps other than made to order? I think the Harrop version was around $1500?

Far out that's ridiculously over priced for the Eaton version then! They were half the price not so long ago

[Red CV8 R]

Far out that's ridiculously over priced for the Eaton version then! They were half the price not so long ago

It does seem expensive, I've seen the Eaton cheaper than even the Tuff car parts price so yeah, nearly double even now. I think you can get the superior WaveTrac for that kind of money too.

[macca_779]

Wavetrac is only any better if you have a zero load condition on one side; ie off road when you c0ck a leg. Other than that the added components add no benefit that i can think of in our applications