The final word on retrofitting the '09 differential

[CTSV_Rob]

You gonna get yourself another Gen 1 now?

[Cadillac Tony]

Two (very) minor updates on this: I talked to Luke, and he had the idea to source custom axle shafts for the rear that would bolt up to our hubs, eliminating the need to replace the hubs, rotors and wheels. The cost shouldn't be more than ordering the 09 axles, but we'll need to wait until the parts show up in the computer before we know what the spline configuration, length and diameter are. Still looking for ways to make this as easy and inexpensive as possible.

On an unrelated note, I got another email from my contact at GM telling me that they just built two "Product and Process Evaluation" vehicles (one stick and one auto) that they'll be using to further test and evaluate the final build process. He's hopefully going to be able to drive them and share his opinion, but he already said that the idle sounds really mean. He also had this to say regarding the new diff:

I have sent an e-mail regarding the fluid spec. to the engineer tasked with development of the new cast iron rear diff. I failed to ask him while he was here at LGR, but he did say that they have tried to break this new unit and have thus far been spectacularly unsuccessful, so that is good news indeed. He was very bullish about the level of robust engineering that has gone into the part and sounds totally confident.

Things are looking good for a bulletproof rear.

[CTSV_510]

I think I speak for everyone when I say thank you Tony and Luke!

[The Tony Show]

Edited - nevermind.

[StealthViggen]

Originally Posted by Flyboy

I just mean that the 08 CTS diff and cradle has been updated already. Are we sure there is a substantial difference been the V and regular CTS? Not like There was not a difference on the first gen cars..

[HiTechRV]

Right. Basically couldn't you mock this up with parts from an 08 CTS (say a totaled car), then swap in the V parts when available?

[StealthViggen]

My thoughts exactly. Surely if the V2 has a better diff yet, then thats a swap, but the main problems here are the full bolt up of the cradle and associated components. The diff will just sit in there once that's sorted.

[TrazzNJ]

[heavymetals]

Hey guys, if your serious you should be talking to someone about a gas tank.

It has already been pointed out that it will need to go.

[rand49er]

Maybe didn't read this closely enough, but if this is primarily just a diff swap (from a drivetrain standpoint only i.e. excluding the fuel tank), is there any way to provide axle shafts with substantially different torsional rigidity in order to reduce/eliminate wheelhop?

I mean, if the biggest difference is simply going to be the diff, these cars are still gonna hop like a 'roo on 'roids.

[lunarx]

Originally Posted by rand49er

Maybe didn't read this closely enough, but if this is primarily just a diff swap (from a drivetrain standpoint only i.e. excluding the fuel tank), is there any way to provide axle shafts with substantially different torsional rigidity in order to reduce/eliminate wheelhop?

I mean, if the biggest difference is simply going to be the diff, these cars are still gonna hop like a 'roo on 'roids.

It's true that the car could still hop.

However, a full 09 retrofit (mayb even a 08 retrofit) with improved diff to cradle attachment and updated half shafts, should make it much better than it is now.

[Cadillac Tony]

When talking to GM I've been working on finding out the details on a complete rear replacement- diff, axles and cradle. The new cradle brackets for the diff take the bolts vertically instead of horizonatally, which should help quite a bit with deflection under load (along with stiffer bushings). The new axles are not only stronger, but also unequal in size and torsionsal stiffness which will help reduce the oscillation that makes it hop. Finally, the cast iron diff is there and able to take the punishment when you hook, or if the road conditions happen to cause a hop (which WILL still happen from time to time, even on the best cars).

The idea originally started with the hope that we could just bolt an '09 diff into our cradle- that would have made it last longer, but still not cured the hop. Turns out that won't work, but the bright side of the extra work needed is that it will also reduce the wheelhop by changing the necessary supporting pieces.

[4DoorGTZ]

Contemplating a quick fix for my newly imploded rear. Sourcing a used rear to let me drive the car this summer.

Hope to go ahead with the ''09 retrofit by...... fall/winter?

I'd be willing to drive cross continent for the work Can I camp out in the Lindsay parking lot, as long as there's wifi and power I'm good to go! (seriously tho, anyone thought of the logistics of getting this done far away from the east coast?)

[lunarx]

Originally Posted by 4DoorGTZ

Contemplating a quick fix for my newly imploded rear. Sourcing a used rear to let me drive the car this summer.

Hope to go ahead with the ''09 retrofit by...... fall/winter?

I'd be willing to drive cross continent for the work Can I camp out in the Lindsay parking lot, as long as there's wifi and power I'm good to go! (seriously tho, anyone thought of the logistics of getting this done far away from the east coast?)

I'm already qualifying 2 potential shops to do the work, once the parts can be purchased.
This is one mod I can't wait for.

[zxmarekxz]

great job guys, now theres hope!!!

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