VE Diff

[J_D 2.0]

May be the case that the Eaton unit they sell is different from the standard Eaton unit but nowhere does Harrop actually state they manufacture the diff centre.…

Within the download section, the Harrop Truetrac PDF does state “Proven Harrop developed design withstands over 500rwkws” but that’s it… So many companies design stuff and have them built in China where QC/QA can be a challenge…

Not saying Harrop centres are made in China, just that if they were made in Melbourne, you’d expect that to be publicised on their website. But nada,… doesn’t state that they cast or machine anything...

So it may just be a specific centre that they‘ve designed and is actually built for them by Detroit or some other machine shop (in China?). Who knows unless they are asked and tell us..

Sounds like its a Harrop design that uses Eaton’s Truetrac design/patents and made for Harrop by Eaton.

 

[losh1971]

https://supafspares.supplies/shop/driveline/lsd’s/torque-lock-gm-ve-commodore/

These are the ones that some sellers are passing off as Trutrac. They sometimes refer to them as a Trutrac but they are a cheap copy.

 

[losh1971]

I just tried to find one on eBay but I can't find any listings with the above centre called Trutrac. The ads used to have Trutrac tacked in the title somewhere. Plenty of these on eBay but the Trutrac part in the title seems to have been dropped.

Funny thing is a few months ago there were listings with Harrop Trutrac in the title too. However, I can't find any of those now either?

 

[Skylarking]

Aussies are tight arses, I remember a few years back I think an M80 Eaton Truetrac was something like $600 or $700, and the Harrop one was like $1200, so you can guess which one they went for.

Also for a licensing agreement to produce a patented product or design, there might be specific clauses that limit what Harrop can say about their diff or how they can advertise and sell it. Could also be how the licensing is structured, as in Harrop might not make as much as they would have liked to do large production runs because of the amount of money they would have had to pay to Eaton, so they make them to demand or something.

TBH I'm surprised a company as big as Eaton would say yes to licensing out a design to Harrop that is by comparison tiny.

Normally when a company states “patented“ they always list patent numbers somewhere. So it’s a little odd that Eaton doesn’t seem to list patent numbers on their website, brochures or stamped on their products...

So I tried to find info on when Eaton actually patented the parallel axis planetary helical gear mechanism used within the Detroit Truetrac but to no avail And why would the patent be interesting, well because patents generally provide 20 years of protection from date of filing

Interestingly I did find the following:

US5620389A - Parallel-axis differential - Google Patents

In a parallel-axis differential, pocket pairs are formed in an inner periphery of a housing and planetary gear pairs are rotatably received in the pocket pairs, respectively. With outer peripheral surfaces of the planetary gears (i.e., top faces of helical teeth) being in contact with inner...

patents.google.com

WO1994019622A1 - Parallel-axis gear differential with limited edge contact between gear members - Google Patents

The first seems it’s a Jap invention of the Torsten diff dated 1994 while the second is from others in 1994. But I’m no expert and reading patents is complex legalised technical jibber jabber so it’s hard to know what is what. All I know is that I haven’t found anything in my short search that seems to emanate from Eaton.

Regardless, a 1994 or 1995 filing would mean that the technology protected by the patent would have actually expired in 2014 or 2015

(and interestimgl6 I’ve read on other forums people have bought Truetrac back in 1990 )

So you'd think one should be able to find a later patent that’s assigned to Eaton which would clarify what their “invention” is and when their protection would expire But nada in my quick search as mentioned. Maybe Eaton doesn’t have the protection it claims via the text “patented” which they splash around

Maybe we need to ask Harrop what they actually produce was under license and whether the Eaton Truetrac is still protected by Eaton patent or whether they just licensed then trademark.

Regardless of such stuff, if Harrop was selling a diff at almost twice the price of a competitor for little benefit as seen by buyers, they’d probably not sell many unless the numbears wanting the extra torque capability were large enough to make it worth while.

As is, the Eaton Truetrac are made in Taiwan and maybe Harrop just didn’t see a big enough market for >500hp torque sensing diffs, couldn’t compete with Taiwans price, and didn’t want to pay for the marketing to build up their own diff trademark so just licensed the Truetrac trademark (which last as long as Eaton keep paying trademark reregistration fees).

Interestingly, there are 3(6), 4(8) and 5(10) shaft(pinion) Truetrac designs, the later used in Ford 9” diff housings..

 

[Davomac7]

From what I’ve read online the Truetrac name is owned and made by Eaton so I think that it’s actually a Eaton Truetrac and Harrop just sell them.

https://www.harrop.com.au/shop/products/performance-driveline/detroit-harrop-truetrac


https://www.eaton.com/content/dam/e...c/eaton-truetrac-differential-brochure-en.pdf

I think like the eaton superchargers harrop makes them here under licence so the harrop eaton trutrac diff is rated stronger than the yank eaton one

 

[Davomac7]

I have no issues with my Harrop Truetrac, it’s great and would recommend one for sure. Mine isn’t noisy which I have heard they can be, you can feel it a little when you have a fair bit of steering lock in and slowly take off (slight shudder) barely worth mentioning but it’s there.
Glad I did it, does help keep it straight(-ish) more than the stock one would.

do you feel you have superior straight line grip if you tromp it ?

 

[MrBags]

Not really, no. Car is supercharged so it’s probably not a fair representation though.

 

[Davomac7]

Not really, no. Car is supercharged so it’s probably not a fair representation though.

Mine is SC as well with similar RWK so was interested in your thoughts but if you feel no real gain in traction then maybe I well leave it as my standard diff is ok for now . Did you feel any real benefit through corners or in wet etc or was main reason you changed was the standard diff was cactus ?

 

[losh1971]

It would be worthwhile upgrading to a Harrop or KAAZ regardless as the stock LSD doesn't cope well with high torque numbers.

 

[Skylarking]

It would be worthwhile upgrading to a Harrop or KAAZ regardless as the stock LSD doesn't cope well with high torque numbers.

From what I’ve read, it’s not really just a torque issue because anything will break if you put more power through it than it was designed to handle.

I think it’s fair to say that the standard VE/VF LSD doesn’t cope well even with standard power when you reach the point where you have worn out your clutch packs, which is inevitable.