NHTSA investigating Rear Diff Issues

[ToyCTSV]

Originally Posted by The Tony Show

There's plenty of Corvettes with broken diffs from wheelhop, and Vipers, and Porsches, etc, etc.....heck- a forum member posted up recently about his FWD Saturn wheelhopping like a sonuvabitch!

Do a search on any Corvette or Camaro forum for "wheel hop" and you'll get 10 pages of threads.

Sorry but I've never experienced this - I've personally owned, driven, and raced numerous performance cars including f-body cars - auto and manual Camaro SS's and Z28's with no wheelhop. Mustang GT... no wheelhop, Supercharged MR2... no wheelhop, Porsche 944 turbo... no wheelhop, Porsche 911... no wheelhop. My C4 corvette.. (425hp) no wheelhop... and a ZR1 C4 corvette ...no wheelhop... and a C5 Zo6 no wheelhop. This includes driving on street tires, race tires, drag radials, snow tires, etc... I'm not trying to be a smartass here but it's clearly a case of a poor design in the cadillac rear end.

edit: I left out the Viper GTS and Mustang Cobra I raced last summer - no wheelhop

[ZEUSROTTY]

Originally Posted by The Tony Show

I'm concerned about some "up and comer" trying to make a name for himself by turning wheelhop in a CTS-V into a horrific safety issue, ignorant of the fact that wheelhop can happen in just about any car.

mine hops in the snow, in a little water, under hard excelleration, low acceleration or whatever... right corners whereever there is low traction...

[ctsv154]

Originally Posted by ZEUSROTTY

mine hops in the snow, in a little water, under hard excelleration, low acceleration or whatever... right corners whereever there is low traction...

^^^What he said! It will hop if you spin the tires in grass! Any time the tires spin and your in a straight line, it hops, no matter how slick the surface may be.

[ODI]

Originally Posted by onebadcad

Wow, only took 21+ months to contact you. The Gov is sure getting more efficient.

There was a sticky for the NHTSA interest over six months ago, nothing ever came of it. You can reply if you chose, but do not expect much action.

Excuse Me?

Detroit Free Press December 22, 2007
GM recalls 313,000 vehicles worldwide

General Motors Corp. recalled more than 313,000 Saturn, Pontiac and Cadillac vehicles around the globe to fix a rear-axle seal that may leak and cause the cars to lose control and crash.

In the United States, the recall covers 275,936 Saturn Sky, Pontiac Solstice and Cadillac CTS, CTS-V, SRX, STS and STS-V vehicles from the 2005-07 model years, according to the National Highway Traffic Safety Administration's Web site. It is GM's biggest domestic recall in 2007.

A fluid leak in the rear-axle pinion seal may cause the vehicles' rear differential to lock up, possibly causing a loss of control, GM said in a Dec. 19 letter to NHTSA.
Two crashes were reported, GM spokeswoman Carolyn Markey said; one involved an injury.

The recall stems from a preliminary inquiry that NHTSA began in July after receiving 20 reports from motorists of rear differential failures. Almost all the complaints cited the back wheels of the vehicles locking up, the agency said.

[TrazzNJ]

[quote=ToyCTSV;1397155] I'm not trying to be a smartass here but it's clearly a case of a poor design in the cadillac rear end.

Um........did he really just type that and click the submit button??

[onebadcad]

Originally Posted by ODI

Excuse Me?

No excuses needed. Made the comment regarding the response time. Twenty-one, probably closer to twenty-two, months to respond is not good customer service.

Regarding the recall, you can take credit for that as an ODI (Office of Defects Investigation) employee. Many complaints were filed by Forum members prior to July 2007, most were done at least a year before that date.

Many V owners have concerns beyond the seal issue, specifically the reliability and durabiity of the rear-end; many also contend it was under-engineered for the stock V's power. Warranty repair denial by dealers whose claims of driver abuse is also well documented, even though the V is marketed as 'Performance' sedan.

Kudos to your Agency for initiating the recall, but to many it is just a band-aid on a much bigger sore.

[urbanski]

Originally Posted by ODI

Excuse Me?

Detroit Free Press December 22, 2007
GM recalls 313,000 vehicles worldwide

General Motors Corp. recalled more than 313,000 Saturn, Pontiac and Cadillac vehicles around the globe to fix a rear-axle seal that may leak and cause the cars to lose control and crash.

In the United States, the recall covers 275,936 Saturn Sky, Pontiac Solstice and Cadillac CTS, CTS-V, SRX, STS and STS-V vehicles from the 2005-07 model years, according to the National Highway Traffic Safety Administration's Web site. It is GM's biggest domestic recall in 2007.

A fluid leak in the rear-axle pinion seal may cause the vehicles' rear differential to lock up, possibly causing a loss of control, GM said in a Dec. 19 letter to NHTSA.
Two crashes were reported, GM spokeswoman Carolyn Markey said; one involved an injury.

The recall stems from a preliminary inquiry that NHTSA began in July after receiving 20 reports from motorists of rear differential failures. Almost all the complaints cited the back wheels of the vehicles locking up, the agency said.

sorry
the recall is only for leaking fluid
NOT wheel hop, NOT broken cases, NOT whine.
the past NTHSA threads addressed every facet of the problem, the leaking being a very minor complaint.

[rand49er]

Originally Posted by urbanski

sorry
the recall is only for leaking fluid
NOT wheel hop, NOT broken cases, NOT whine.
the past NTHSA threads addressed every facet of the problem, the leaking being a very minor complaint.

The faulty pinion seal and the diff failures brought about by the diff being underspec'd for this application are independent of each other. In other words, you can have one and not the other.

On another issue, I did hear a rumor that NHSTA might be sending investigators to some of the larger and/or more visible Cadillac dealerships and are poking around.

[CopperHead]

I live in Colorado...wheel spin is a daily occurance. We have snow and gravel all over the roads. So wheel hop is a huge safety issue. My car only has 23,900 miles on it. It is going in on Monday for its fourth rear differential. I have numberous defects, yet GM is trying to screw me in a repurchase. They need a lesson in doing the right thing, and I hope that NHTS teaches them that.

[ToyCTSV]

Originally Posted by TrazzNJ

Um........did he really just type that and click the submit button??

yup lol

I think the only other vehicle that I've ever personally experienced wheelhop in is a pickup truck. I think on a truck it's due to a stiff spring rate because trucks are generally designed to carry a heavy payload. The CTS-V has a stiff spring rate (as do most performance cars) but I wonder if a softer spring rate could potentially decrease the wheelhop characteristics without sacrificing handling?