I R S,(rear end), Question, as a donor....

I was walking around under a late model Caddy, (C T S ), at my buddy's muffler shop today, and was checking out the I R S on this heap..........

Anyone familiar with them, as to how much power they will stand, and abuse they might take?????

I believe the name "Getrag" was on the drivers side axle stub bell.

Fairly compact unit, I thought.

Please , tell me what you know about the setup.

Thanks.

 

Trans-axle?
Should be same as late model 'Vette.
From the looks of the car, it's the same size as the new GTO.
If it is that rear-end, they have run an LT small block through one.
You aren't going street rodder on us, are you Chuck?

 

Alright. It's called a Getrag 645. Used in several recent cadillacs.

I haven't been able to find the exact torque rating for a CTS- But the minimum for this type of diff. is 720 foot pounds of torque. Ratio for the CTS is 3.43 and 3.73 for the CTS-V.



Looks quite modern but there's something to work with for sure.

Manufacturer's spec list is here:

 

No transaxle...........I R S, with the chunk, and upper and lower control arms and strut rods and what not, all mounted to a removable frame................

I got yer street rodder, right here!!!!!

Looking at a mid 60's Dodge window van, that is just begging to be mid engined, and I have some Mopar B and RB powerplants, and some TorqueFlites, and a flat floor, and some chalk, and some time...........
And no, I don't want to put a Jag in it, no matter how trad.....

 

I like where you're head is at. Midengined vans are the bee's knees!

Regarding the Jag IRS. Sure it's trad. But that's the sorta thing you'll find chromed in 60's T's. Kinda clashes with what you're envisioning.

Can't wait to see where you're going with it!

 

Same diff is used in the Camaro as well, to the tune of 450hp.

As long as you don't have axle hop during a burnout, it'll live forever. Severe hop can bust the pinion gear.

 

720 ft-lbs of torque...Hmmm.
Chuck, I did not know you were an A-100 fan.
I still have that A-108 that was behind the shop.
Sounds like a fun project.

 

That's cool.......As I was eye-f#%^in' the drive train in this thing,(it was a v-6 Caddy), I was admiring the rear end and driveshaft, wondering if it would live behind a semi-mild 440, with a 4bbl. and headers.

I looked over the outside, and saw no I.D. tags of any sorts.............How would a fella' decipher whether it is a limited-slip, and the ratio??????

Would it be V I N decode only????

And yes, I wanted to steer away from the Jag, to get away from the coil overs, and the inboard disc brakes..........Although I know there is a lot of stuff out there for it's Dana 44 lineage!!!!

This axle has has a park brake mini drum deal, inside the brake disc.....

 

And Stevie G.................Dig out that spare set of headlight bezels........I know ya' got them!!!!!........Don't be holdin' out on me!

 

Woah!!! A Little Red Wag-er Van!!!

 

I've searched the internet dry it feels like and I haven't been able to find something beyond what I already posted. Except it seems it's LSD in most of the versions.

If you had the year of manufacture/Engine/Trans options you might be able to find something. Otherwise the car's service manual I guess. Let us know where it takes you.

-Andy

 

Somewhere around '88 Jag moved the brakes outboard if that helps.

.

 

I think with any late model, if you take a VIN down to a dealership, then can run a computer check and produce a copy of the actual window sticker on the car. And that should tell you the ratio and whether or not it's a posi....

When I was looking at used Jeeps, I did that a few times.

 

I would dig the setup under the new chargers under a fat fender car, one out of a totaled hemi car should hold most abuse, plus it's a drop out unit. Kinda looks wierd but under a driver no one would see it.

 

This might be another option for you. This IRS set up is out of a 88 or 89 lincoln mark 8. I was told it is fairly strong and has an electronic posi

 

The Lincoln Mark VIII is a great low cost option you can find them on craigslist for about $200 to $300 and they use a ford 8.8 third member so performace parts are easy and cheap. Mustang guys are a great soure for parts for them. I have a Lincoln Mark 8 rear suspension in my 28 Willys matched up with a 5.0 BMW V12

 

if you take the vin to a gm dealer they can bring up the option code for that vehicle
than the can tell you what the codes mean (gear ratio , posi )
i have done this a few time
been a gm mechanic for 20 years so don t let em tell the can t do it
the parts dept has access to all that info

 

Thanks for all the info, gang.................That Lincoln Mark VIII looks do-able as well!!!!

I was thinking the Ford 8.8,......I thought it was a "chunk" or drop out center section type?????...........
I can't see this provision in the photo.............

E X K and vtwinpartss....................Are you speaking of the same setup?????

 

It looks like the Getrag differential bolted to the rear of the C5/C6 Corvette transaxle - both the automatic and the T 56 6 speed transaxle. This also does duty in the ZR1 with 638 hp and 604 ft lbs. so I doubt if you are going to have problems with putting large amounts of torque through it.

 

Got any pics of the BMW v12 ?

Building myself an wild toy and even thought of running 2 buick straight 8 side by side

 

Weasel......................Is that laying in your shop??????????..........What are YOU up to?????

 

I will post some this weekend.

 

Got a little stash of C5 stuff, but ssshhh - not HAMB compliant.

 

Understand!

 

Btt.................Any more guidance and infinite wisdom, or pics from one of those Lincoln Mk. VIII setups???????

 

Can't say I have infinite wisdom or a Mark VIII for that matter.

However, I found the RPO codes for the cadillacs. If you get the RPO code of the caddy in question I should be able to find the ratio and if it's posi.

8.8 Sounds nice as well, saw a 5.0 Mustang with Mark VIII running gear transplant. Think it was a recent Hot Rod tech piece. Let me check my archive, however limited.

 

Thank you, Sir......

 

The cts IRS is known as a massive failure in the caddy world. They fail while cruising or under load in the v6 model and in the v8 cts-v model. Something siezes inside and cracks the housing.

I am currently using an 03-04 mustang cobra IRS in my project. They can take alot of power, they are fairly light weight and can be tuned very well in the handling department.

 

As far a the Lincoln Mk. VIII rear, it will handle some serious power. Dude around here has one in a r@# rod, blown 454 runs high 9's with some wide ass dirt slicks

Later,Mark

 

I am on my way to pull one out now. 97 Mark VIII ThunderBird and Cougar from the mid 90's had the same IRS the only difference is the Lincoln has Air Bags and the SC or cougar has coil springs. I will take detailed photos of the IRS and post them when I get home.