Advice needed

[LS1VT]

I think this might be a pretty good deal.
What is a realistic price for labour to have this fitted?
https://www.tuffcarparts.com.au/vt-v...eaton-truetrac

[whitels1ss]

I think this might be a pretty good deal.
What is a realistic price for labour to have this fitted?
https://www.tuffcarparts.com.au/vt-v...eaton-truetrac

Yeah looks good, I checked my invoice, I bought my centres from them also.

I would guess you should get it done for under $1,000 but might find someone for a bit less if you are lucky.

[BLACK 346]

Got another quote today, I did ask for a truetrac & this was the reply
1 x OEM Dana Spicer 3.73ratio gear set $575.00
1 x Bearing overhaul kit and labour build differential $795.00
Total: $1370.00
Fitting service also available if required:
1 x Remove and refit differential assembly and gear oil $460.00

Cost me $2980 at Precision Diffs in Adelaide with OEM 3.73 and Eaton Tru Trac. This was December 2021 and was changeover for old Diff. Totally transformed the car though, no more stepping out under WOT, just straight as an arrow now and much safer to drive.

[SASLS1]

You can buy an Eaton Trutrac for heaps less than buying a Harrop Trutrac

Eaton is a big engineering company that make only first class gear, Harrop are Eaton dealers
& use their rotors in their superchargers as do many other supercharger manufacturers.

I do not know if Harrop make ALL their own gears and casings for their diff centres
but I am not worried about buying an Eaton instead of going through Harrop.

I reckon I bought my Eaton for under $700 on ebay about 3 years ago.

Reading the fine print, that Harrop price of $1,291.40, is for a " Standard " Eaton TrueTrac, not the Harrop upgraded version.

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

Prices have gone up heaps in the last couple of years, its crazy...

Harrop use to list their prices for their M80 VT - VZ " Harrop " TrueTracs in the past, but they don't anymore, as their prices must be way more... than they use to be.

The Standard Eaton TrueTrac version is perfect for street use, The Harrop Upgraded version is total overkill for a street car.

[SASLS1]

In 2013, I paid $1850 for brand new OEM Spicer 3.91 gears, brand new Eaton Truetrac, full rebuild with new seals, bearing and gaskets.

I removed the diff myself, and reinstalled it myself after the Diff shop built it for me.

So prices have gone up heaps.

[whitels1ss]

Reading the fine print, that Harrop price of $1,291.40, is for a " Standard " Eaton TrueTrac, not the Harrop upgraded version.

That is not a bad mark up over what all the other vendors price the exact same item.

[SASLS1]

That is not a bad mark up over what all the other vendors price the exact same item.

Yes there is a Crazy Variation in price for the same thing.

$860.35 from VPW

https://www.vpw.com.au/parts/EAT-912A642


$1,522.65 from Engine Masters Australia

https://www.enginemaster.com.au/eaton-detroit-trutrac-diffrential-holden-gto-04-06


Always pays to shop around...

[duke5700]

Harrop don't do their version anymore, as Eaton improved their product enough that Harrop said it wasn't required.

I rang up late last year chasing one rather than the purely Eaton product. I wanted to build a spare diff. I mentioned that I was disappointed, I would still of preferred the Harrop version.

Harrop also don't make the CVs for the VT-VZ anymore either. They were ridiculously expensive, like $4500 for the set but you won't find a stronger set.

Reading the fine print, that Harrop price of $1,291.40, is for a " Standard " Eaton TrueTrac, not the Harrop upgraded version.

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

Prices have gone up heaps in the last couple of years, its crazy...

Harrop use to list their prices for their M80 VT - VZ " Harrop " TrueTracs in the past, but they don't anymore, as their prices must be way more... than they use to be.

The Standard Eaton TrueTrac version is perfect for street use, The Harrop Upgraded version is total overkill for a street car.

[whitels1ss]

Harrop don't do their version anymore, as Eaton improved their product enough that Harrop said it wasn't required.

I rang up late last year chasing one rather than the purely Eaton product. I wanted to build a spare diff. I mentioned that I was disappointed, I would still of preferred the Harrop version.

I don't think there would be a big market for them to make their own anymore.
As said previously for a street car it's overkill.

[SASLS1]

Harrop don't do their version anymore, as Eaton improved their product enough that Harrop said it wasn't required.

I rang up late last year chasing one rather than the purely Eaton product. I wanted to build a spare diff. I mentioned that I was disappointed, I would still of preferred the Harrop version.

Harrop also don't make the CVs for the VT-VZ anymore either. They were ridiculously expensive, like $4500 for the set but you won't find a stronger set.

I found this from the Eaton web site FAQ section on their TrueTrac's...

" How much horsepower and torque will the Truetrac handle?

Detroit Truetrac is designed to handle more torque (power) than the axle shafts it drives. Horsepower has little influence on the differential since it is more of a function of engine RPM. Each model of Truetrac is designed to unique torque capacity specifications; however, they are all developed to handle the extreme torque loads typical in professional racing and military applications. The torque limit is largely limited by the “barrel” diameter (the inside diameter of the ring gear) but is also limited in c-clip models by the reduced pinion gear sets due to the c-clip installation pocket. Since these parameters are dictated by the axle design and ring gear strength, the Truetrac differential should not be the limiting component in the axle’s torque capacity. "


Harrop still make their " Harrop " TrueTrac for VE/VF, so the demand must be still there for VE/VF.

https://www.harrop.com.au/shop/products/performance-driveline/detroit-harrop-truetrac/truetrac-holden-zf-32-spline


IMO its Supply and Demand, they had alot of other products for VT - VZ which are no longer available, and only some still being available.

They use to sell exhausts and complete 12 bolt diffs for VT - VZ from memory, which are also no longer available.

[BLACK 346]

I found this from the Eaton web site FAQ section on their TrueTrac's...

" How much horsepower and torque will the Truetrac handle?

Detroit Truetrac is designed to handle more torque (power) than the axle shafts it drives. Horsepower has little influence on the differential since it is more of a function of engine RPM. Each model of Truetrac is designed to unique torque capacity specifications; however, they are all developed to handle the extreme torque loads typical in professional racing and military applications. The torque limit is largely limited by the “barrel” diameter (the inside diameter of the ring gear) but is also limited in c-clip models by the reduced pinion gear sets due to the c-clip installation pocket. Since these parameters are dictated by the axle design and ring gear strength, the Truetrac differential should not be the limiting component in the axle’s torque capacity. "


Harrop still make their " Harrop " TrueTrac for VE/VF, so the demand must be still there for VE/VF.

https://www.harrop.com.au/shop/products/performance-driveline/detroit-harrop-truetrac/truetrac-holden-zf-32-spline


IMO its Supply and Demand, they had alot of other products for VT - VZ which are no longer available, and only some still being available.

They use to sell exhausts and complete 12 bolt diffs for VT - VZ from memory, which are also no longer available.

Is that a Harrop Trutrac or a Detroit Eaton with the Harrop name on it? Can't see anything in the description to say they make or modify it for extra strength. and it seems way too cheap for a Harrop product.

[SASLS1]

Is that a Harrop Trutrac or a Detroit Eaton with the Harrop name on it? Can't see anything in the description to say they make or modify it for extra strength. and it seems way too cheap for a Harrop product.

It's Harrop's Own Manufactured TrueTrac.




Here is the standard Eaton Detroit TrueTrac for G8 / Camaro / VE-VF







Quote from Harrop link below.

https://www.harrop.com.au/shop/produ...n-zf-32-spline

" We are proud to announce the latest Harrop/Eaton Truetrac for VE/VF Models, which has significant improvements over the standard duty version.

Key Improvements

210% Stronger gear set
Larger side and pinion gears
8 pinions instead of 6
Precision cut side gears "


Back years ago the Harrop TrueTrac for VT - VZ was around $1500 from memory, and the standard Eaton Truetrac was only around $500 - $600.

So it would have been very profitable for Harrop back then, as it was Crazy Expensive back in the day.

Today the standard Eaton Truetrac is around ( ~ $700 USD / $1,018.73 AUD ) RRP

So the Harrop TrueTrac price of $1501.51 AUD is still alot more expensive than the standard Eaton TrueTrac...

[duke5700]

Yeah only turkeys like me

I don't think there would be a big market for them to make their own anymore.
As said previously for a street car it's overkill.

[duke5700]

The big thing with the VT-VZ diff is when you have grip and horsepower, it peels the diff housing apart. It distorts, the gears don't mesh properly and you implode everything.

So, like you guys said, the limitation isn't the gearset or the tru trak. I did however crack the containment housing for the gears with an early Eaton one, before they were improved. The early Eaton units also didn't have great tolerances and it tended to make more noise than the Harrop one.

[whitels1ss]

The big thing with the VT-VZ diff is when you have grip and horsepower, it peels the diff housing apart. It distorts, the gears don't mesh properly and you implode everything.

So, like you guys said, the limitation isn't the gearset or the tru trak. I did however crack the containment housing for the gears with an early Eaton one, before they were improved. The early Eaton units also didn't have great tolerances and it tended to make more noise than the Harrop one.

Hey Luke, we have not had a strip over here in SA for a heck of a long time so mine is not set up as a drag car
therefore I can't imagine peeling my housing apart but I am running a built 4L60E
& I can imagine breaking a main input shaft & destroying the transmission again before that anyway.


Have looked at doing a built T400 conversion but I honestly can't justify spending the money
with the trade off that the car would not be as nice to drive on the street as it does now.

(I also have put a fair bit of money into my current transmission which is fine on the street anyway.)