Toyota GR Corolla Forum - Release Date, Specs, Pricing Discussion banner
1 - 20 of 54 Posts

Registered
Joined
35 Posts
Discussion Starter · #1 ·
Hi Folks,

The Boston region just received quite a few core models with no performance pack. Can someone post a VIN for a PP core model and one without the PP? We can cross compare the models and identify which parts differ, what those part numbers are, and how much it would cost someone to purchase the parts to bring a non PP core to a PP core.

Thanks,
 

Registered
Joined
1,888 Posts
The cost to convert to front and rear diffs from the PP would be pretty substantial. The rear would be cheaper, as dropping a diff is a lot less labor intensive as dropping the entire front drivetrain in order to install the front diff. The parts themselves shouldn't be too expensive, seeing as how the PP is only like $1200. Including labor, I would estimate the cost to convert to front and rear OEM torsen diffs including labor to be $2500-$3k.
With that being said, I would not purchase a non PP GRC, even below MSRP. But that's just my opinion. 馃し
 

Registered
Joined
93 Posts
PP VIN JTNABAAE7PA002049
PP VIN JTNABAAE1PA001849
Only the other 2 packages VIN JTNABAAE2PA002086
/ no packages VIN JTNABAAE8PA001959
If you had to settle for a core without PP would aftermarket diffs make more sense? Or will they need more maintenance and be less reliable?
 

Registered
Joined
1,888 Posts
PP VIN JTNABAAE7PA002049
PP VIN JTNABAAE1PA001849
Only the other 2 packages VIN JTNABAAE2PA002086

If you had to settle for a core without PP would aftermarket diffs make more sense? Or will they need more maintenance and be less reliable?
Unless you are really hardcore tracking the car, the OEM torsens will satisfy 99% of GRC owners who occasional track their cars. For those who don't plan on tracking the car, LSD's are really a necessity.
 

Registered
Joined
212 Posts
I would be curious about any calibration differences between PP and Non-PP models for systems like VSC, ABS, and traction control. Given the heavy emphasis on vehicle safety systems these days, I would have to assume Toyota would tune them differently for the two drive trains, especially if they were implementing a brake based E-LSD function on the non-PP cars.
So you may swap in some OEM LSD's at $4k+, but not end up with the same car behavior. Probably none of us would notice any difference, and plenty will be turning these systems off, but it would suck if it threw codes at you.
Is there a separate drivetrain control module to check part numbers on?
 

Registered
21 CTR
Joined
79 Posts
Besides track performance, the car will do much better in any low grip situation. Snow, heavy rain, etc. Unless you only use your vehicle for sedately driving to the grocery store once or twice a week, get the diffs.
I got to experience this first hand in my Type R a few weeks ago when some major winter weather hit. First winter since moving back up north. Despite only being FWD, the LSD pulled me out of a few icey spots where others were struggling. Looking forward to adding AWD to the mix with a GRC.
 

Registered
Joined
83 Posts
the reason I didn鈥檛 want the core / wanted the Circuit was for all of the creature comforts, aesthetics, and diffs.

you don鈥檛 want an open diff car. or to install the parts yourself, unless you鈥檙e planning to do aftermarket diffs. it鈥檒l leave you wanting more. trust.

having a core with the diffs made me think otherwise, tho I鈥檒l be piecing together the CE parts into my vehicle eventually.
 

Registered
鈽 1991 Celica GTFour RC 鈽 2000 Grand Cherokee 鈽
Joined
537 Posts
I'm thinking anyone who isn't triggering traction control warnings in their current AWD vehicle won't notice a lack of PP diffs. Most people aren't going to be pushing hard enough on the street for them to make a difference, even in snow/rain/whatever.
 

Registered
Sienna, GR86, GRC
Joined
287 Posts
I'm thinking anyone who isn't triggering traction control warnings in their current AWD vehicle won't notice a lack of PP diffs. Most people aren't going to be pushing hard enough on the street for them to make a difference, even in snow/rain/whatever.
Granted I do zero laps per year at a racetrack, but I can count just as many times (zero) in 8 years with my open-diff'd WRX when I felt I needed more grip. That includes melting my poor snow tires on a twisty wet road in a December or pulling a fedex truck out of the ditch on my icy street last year. (Pulled out many stuck vehicles, that was the most notable.) Provoking any feeling of traction loss in the dry was basically impossible aside from massively overcooking a turn and plowing into understeer.

That said, it's beyond a shame that Toyota builds a single one of these cars without LSDs. Most people wouldn't consider a WRX STI an STI without LSDs and I totally understand why someone would feel the same about the GRC. All for a grand?
 

Registered
Sienna, GR86, GRC
Joined
287 Posts
Please post the part number and the price for the diffs
No idea. Like Texan said even if you were able to get the Torsen units by themselves (I鈥檒l guess $800 a piece) labor will be a ton. His estimate of $3k including labor is probably quite low. They鈥檙e not a DIY thing on any level either. My brother just had the rear diff on his 64 corvette convertible rebuilt and it would have been close to $2500 if we didn鈥檛 pull the thing ourselves.

If you鈥檙e stuck with a non-PP allocation and you aren鈥檛 going to regularly track the thing, the only real concern you should have is resale. It鈥檚 a valid concern, especially with how few are being spec鈥檇 that way (particularly cruel of Toyota.) Even if they end up making up a third of all GRCs, most people simply won鈥檛 even consider one without PP. If you plan on keeping it long term, no worries.
 

Registered
Joined
35 Posts
Discussion Starter · #16 ·
No idea. Like Texan said even if you were able to get the Torsen units by themselves (I鈥檒l guess $800 a piece) labor will be a ton. His estimate of $3k including labor is probably quite low. They鈥檙e not a DIY thing on any level either. My brother just had the rear diff on his 64 corvette convertible rebuilt and it would have been close to $2500 if we didn鈥檛 pull the thing ourselves.

If you鈥檙e stuck with a non-PP allocation and you aren鈥檛 going to regularly track the thing, the only real concern you should have is resale. It鈥檚 a valid concern, especially with how few are being spec鈥檇 that way (particularly cruel of Toyota.) Even if they end up making up a third of all GRCs, most people simply won鈥檛 even consider one without PP. If you plan on keeping it long term, no worries.
My allocation is fully loaded, so I personally am not worried. The impetus for starting this thread is to assist non PP members with the information they need to piece together the upgrades for the PP specification.

I am assuming that this forum has readers capable of pulling and swapping diffs.

I think what will be most exciting when we cross compare models is which other parts are unique to the PP core models.
 

Registered
鈽 1991 Celica GTFour RC 鈽 2000 Grand Cherokee 鈽
Joined
537 Posts
No idea. Like Texan said even if you were able to get the Torsen units by themselves (I鈥檒l guess $800 a piece) labor will be a ton. His estimate of $3k including labor is probably quite low. They鈥檙e not a DIY thing on any level either. My brother just had the rear diff on his 64 corvette convertible rebuilt and it would have been close to $2500 if we didn鈥檛 pull the thing ourselves.
Redoing a whole rear end like that is a totally different scenario. Bolting in a complete rear assembly, especially on a brand new car, is going to be quite easy and take minimal labour.

The front it going to be a different story. From what I gather it's set up the same as most transverse vehicles so you need to open the trans which means removing the trans which means removing the engine. That gets pricey fast.
 

Registered
Joined
35 Posts
Discussion Starter · #18 ·
Redoing a whole rear end like that is a totally different scenario. Bolting in a complete rear assembly, especially on a brand new car, is going to be quite easy and take minimal labour.

The front it going to be a different story. From what I gather it's set up the same as most transverse vehicles so you need to open the trans which means removing the trans which means removing the engine. That gets pricey fast.
Is it true that one has to remove the engine to drop the trans? There is a brilliant technician in the UK called Williams Mobile Clutch service that drops transverse transmissions in a matter of hours. Check out his YouTube channel. The point is that I鈥檝e not once seen a video of him doing this work while also taking out an engine.

Replacing diffs is involved, but I doubt that it is out of scope for some here.

If anyone has the PN for the front differential, please post it here.
 

Registered
Joined
592 Posts
Is it true that one has to remove the engine to drop the trans? There is a brilliant technician in the UK called Williams Mobile Clutch service that drops transverse transmissions in a matter of hours. Check out his YouTube channel. The point is that I鈥檝e not once seen a video of him doing this work while also taking out an engine.
That's going to depend on a few things. Some smaller cars tend to have a subframe that doesn't surround the whole drivetrain area. It also depends on how much clearance there is between the back of the transaxle case and the fender apron on that side. Then you throw all-wheel drive into the equation, and that changes the entire situation. On most all-wheel drive Toyota products, the transfer case actually wraps around the rear ears of the block. Therefore you cannot just slide the transaxle backwards in any case without separating the transfer case from the transaxle case. Sometimes that is simply not doable with the whole assembly in the car. On many vehicles I had to drop the entire subframe with the engine and trans still mounted to it, and then work on separating all the components. There is no one answer for all models, and I've not seen what the bottom side of a GRC looks like. I will say that in the last few years Toyota got a little better about making the transfer cases slightly more compact, and therefore making the bolts that attach it to the transaxle case more accessible. This improved your odds a little bit of being able to separate the transaxle from the transfer case in the car. But again, there may not physically be enough room to pull the transaxle back far enough for the bell housing to clear the flywheel and in this case the clutch assembly to get it out of there. I don't believe we'll actually know the answer to your question until someone tries.
 

Registered
Joined
151 Posts
The Cusco front diff is LSD 1C7 V15 and runs $1800. Looks like the assy with case is 41301-52340 - $5,500. Maybe someone can look up just the diff part.

On a GRY forum they said you have to split the transmission case to get to the diff.

Supposedly you can buy a whole used transmission and just swap that.
 
1 - 20 of 54 Posts
Top