blckbrd84

It was for a clunk in the rear suspension. Basically they replaced the rear suspension subframe bushings. Yes cars with the problem were known to exhibit extra wheelhop which seemed to be mostly resolved with the fix.

It affected only the beginning of the 2004 GTO's. Mine was built afterwards with the correct bushings.

It will wheelhop bad if you try to rev it up to like 5 grand and dump the clutch but if you launch it right it digs in nicely with no hop at all. I actually cut a better 60' with the GTO then I did with the WS.6 stock for stock.

Chris

TTopJohn

The CTS-V has left a bad taste in a lot of mouths because of its weak IRS setup. There are countless complaints about it on the web and even in R&T's long term test updates. Noise, slop, and outright failure. It's to the point that I'd never consider a CTS-V even though I really like the car, I just don't want to deal with a noisy clunky rear end, especially on a luxury car.


That said, there are a lot of IRS cars out there with no such issues putting tremendous amounts of power to the ground - some of them even made by GM. So a good IRS can be designed, and I'm pretty confident that GM isn't going to repeat the same mistakes they made on the current CTS-V.

Z284ever

The issue with the CTS's IRS is related more to harmonic energy, propogated from the engine cradle back to the IRS, than it is with lack of strength. Most of the failures have been from diff cases cracking because of this energy as it creates wheelhop.

The diff case on my '06 CTS is reinforced, compared to previous ones....but axle hop is still an annoying problem. One thing I've noticed though, is if the car is not pointed completely straight...even just afew degrees of variation.....that the wheelhop won't present itself. The reason being, is that this slight variation, is enough to cancel out the propogated wavelength of energy which causes the axle hop.

Weird, but GM is aware of it.

TTopJohn

If the diff case failures are from wheelhop, are the clunks/whines/and driveline slop also from wheelhop? Or are they from a weakness in the rear end? I've read of a lot more gear whine, clunking, and driveline slop than completely broken rear ends.

Z284ever

AFAIK, most of the failures are secondary to the wheelhop issues. The Getrag diff has been accused of not being beefy enough - which may be true, since no one ever thought a 400 horse smallblock would rest under the CTS's hood when it was being developed.

But alot of the whining (as in noise) issues are directly related to the deflection that's part of the wheelhop issue.

R377

CTS differential failures are by no means limited to the V cars. Plenty of V6 A5 and M6 cars have had experienced failed diffs (and suffer from wheel hop too).

Z284ever

That's true.

TTopJohn

Was not aware of this - which Caddy board(s) or other sources are you getting this info from? I'd like to do some research, though I'm pretty sure I've heard enough to rule out a CTS and just get one of the RWD Daimler Chrysler cars in 340 or 425 hp form instead if I got the jones for a faster RWD sedan.

R377

Here's a good start: http://www.cadillacforums.com/forums...lac-cts-forum/

But aside from that, I've put plenty of miles on a V6 CTS and can vouch for the wheel hop issue first hand. No differential failure though.

teal98

Well that clears it up

Z284ever

Glad to help.

Z284ever

Yeah, do a search on Cadillacforums, there was a pretty interesting poll afew months ago regarding CTS diff failures and who gets them.

EDIT: Here it is,
http://www.cadillacforums.com/forums...ight=diff+poll

teal98

Sorry I pissed you off, or you didn't like my comment. If you can enlighten me as to the misconceptions, I'd appreciate it. I guess number one is that the CTS wheel hop problem isn't from the IRS?

TTopJohn

Thanks for the info on the CTS rear diffs! I'm not exactly in the market, but a CTS-V or possibly a 3.6 Sport Lux is always sort of on the radar screen.

SunsetHawkSelena

we have an 05 GTO and we drag race it and autoX it and the IRS is holding up just fine. at the drag strip we did have some wheel hop, but a set of drag bags clears that right up. i think the new Camaro will be a-okay with IRS