I have a 2005 Cadillac ctsv with a faulty rear under-engineered rear carrier unit that supports the rear differential. It is leaking. Cadillac has replaced these units with the same faulty under-engineered units manufactured by getrag with 2006 units. This solution has been nothing more than a band-aid and the result of the leaking is faulty engineering as determined by several highly respected engineering companies such as lingenfelter and katech that GM does there actual outsourcing to. I am very concerned to drive this vehicle out of fear that the rear end will fail and cause me to lose control of the vehicle and cause property damage and possible fatal bodily injury. Rather than Cadillac issuing a recall to replace this unit with a properly engineered unit to support the rear wheel torque that is generated by this vehicle; they have instead hid behind a technical service bulletin and handle these cases on a case by case basis. I remain hopeful that you will take action before we are dealing with another Firestone tire issue as Cadillac was made aware by getrag that this rear carrier differential was not "up to par" with the engine that they installed in the 2004 and 2005 Cadillac ctsv.

- Forest Hill, MD, USA

August 2005, 4 months after purchasing car, both rear tires worn out from the inside out with 4000 miles on the car, took car in for warranty on tires and rear end, GM denied claim. Had to purchase 2 new tires and have the frame aligned. January 2006, car slightly hits curb and right rear causing no damage to tire and scrap to wheel, rear differently broken and axle, again GM denies claim.

- Houston, TX, USA

Failed rear differential: Case cracked, spilling differential oil onto the rear of my car, rear wheels, street. Car began to grind, had to limp to dealer, still in shop after 1 week with no word on when it will be fixed. Thankfully no injuries, but 2 quarts of oil dumped onto the exhaust, tires and street could have been a major problem.

- San Antonio, TX, USA

I have a 2005 Cadillac Cts-V with 17800 miles. It has developed a whine in the rear differential. Upon investigating further, I found this has not been unusual for this model. (GM has used the same differential in this car as they put in the base Cts model, which has significantly less torque) upon taking the car to the GM dealer, they said they would have to replace the differential, but would have to await parts to do so. They are to call me when they get the parts in stock. They also said the clutch has been updated and have ordered a new clutch also.

- Bradenton, FL, USA

Rear whine in transmission, dealer states is normal.

- Long Beach, CA, USA

Whining from rear end. Rear differential replaced.

- Covina, CA, USA

Took delivery may, 2005. In less than three months, with approximately 1,500 miles, differential began to whine at speeds between 45 and 50 mph, once up to normal operating temperature. Vehicle currently has ~5,200 miles. Differential now whines between 40 and 55 mph. There seems to be a consensus among many Cts owners that this condition is a precursor to complete, and sometimes sudden, differential failure.

- Gadsden, AL, USA

The differential in my car has started to whine after ~11K miles despite, perhaps, the least abusive driving that is reasonably possible, especially considering that this car is a Cts-V. to say I am disappointed would be an understatement. After a little bit of investigation, it appears that GM has used an under-engineered part for its differential for reasons I'm not real certain of. Multiple failures are being reported all across the country, many with similar driving habits that I have. The Cts-V differential is a limited slip 3.73 application and requires ~ 7% friction modified oil. Such fluid was changed several thousand miles ago as a precautionary measure and the proper oil was added. I plan on taking my car in for evaluation/service in the near future, but I believe that gms decision to install a clearly known "bad" part is wholly egregious.

- Santa Paula, CA, USA

1-rear end wine high pitch 2-rear differential defect 3-replaced with an 06 differential & three weeks latter leaking oil.

- Lynbrook, NY, USA

Vehicle has moderate to severe wheel hop during acceleration or when roads are wet or slick, causing some lose of control. Rear differential had loud whine and is prone to catastrophic failure.

- Florence, KY, USA

With only about 3370 miles on a brand new car, my rear differential internals were destroyed and the housing cracked due to the following 2 reasons: 1. excessive wheel hop due to a poorly designed rear suspension 2. the differential that comes stock in every 2004-2005 Cts-V Cadillac is not rated to handle as much horsepower and torque as the car puts out. GM cut corners and put in a differential that was meant for their V6 base model Cts that makes about half the power. When the rear differential blew up, it also destroyed my driveshaft. I noticed the differential over time started to whine and clunk more and more and become louder and louder until all of a sudden while driving I heard a loud boom and a bunch of clunking and metal grinding. The car was immediately undriveable. My dealership replaced my driveshaft and the differential with a 2006 Cts-V differential which is a beefier piece. I have 2500 miles on the new differential which is already starting to whine and clunk. Wheel hop is still atrocious and it is only a matter of time before this differential breaks as well. My dealership denied knowledge of any issues with Cts-V rear ends, and tried to place the blame on me by stating that my rear tires were very worn for only 3370 miles, so I must have been abusing that car. That is not the case, and these tires are notorious for having the worst tread wear of any tire on the market, and every Cts-V owner complains about how long they last. In fact, consumers gave the tires on this car the worst rating of any tire listed on "the tire rack." See here: www.tirerack.com/tires/tires.jsp?tiremake=Goodyear&tiremodel=Eagle+F1+supercar+emt consumers rate the tire wear as a 2.6/10. What a joke, and Cadillac dealerships place the blame for the tire wear on me the owner.

- Phoenix, AZ, USA

4/11/05 - 8,367 miles - 1 day out of service rear end failure 4/28/05 - 9,664 miles - 5 days out of service rear bushing failure. Rear end failure 5/5/05 - 9,720 miles - 1 day out of service rear end failure wheel delivered from factory will not balance - no sign of damage 7/25/05 - 15,732 miles - 4 days out of service PCM recall #05544 - dealer unable to reprogram rear end hops wildly in rainy or slick roads when accelerating hard shifting into 1st gear rear end whine drive line clunk parking brake goes to floor and won't stop car rear end failure - dealer replaced rear differential and did not add friction modifier, claimed Cts-V's do not need - later determined this was incorrect 8/29/05 - 17,372 miles - 22 days out of service rear end grinding friction modifier added transmission rebuilt replaced pressure plate replaced clutch - tsb 05-07-31-001 rear end bushings installed to reduce wheel hop tsb 05-04-114-001A navigation system replaced after all buttons were peeling parking brake goes to floor and won't stop car PCM recall performed 10/6/05 - 18,990 miles- 0 day out of service navigation system not programmed properly by dealership - returned for repair 11/5/05 - 22,151 miles - 0 day out of service replace all center caps on wheels - peeling 1/2/05 - 27,171 miles - 10 days out of service rear end failure radiator failure tsb 05-06-02-005A sun visor replaced due to peeling 1/19/06 - 27,538 miles - 6 hours out of service PCM removed and replaced at gordon histed's request 1/26/06 - 28,000 miles - 2 hours out of service navigation system removed and replaced 2/2/06 - 28,500 miles - ? transmission failed again - won't shift into reverse 10 service visits in the last 9 months 44 days of out of service in the last 9 months.

- Chesapeake, VA, USA

Differential failure.

- Las Vegas, NV, USA

Rear-end differential failure, transmission failure.

- Valley Stream, NY, USA

When driving in rain / poor weather, the car during take-off violently shakes when the rear wheels spin. This shaking has thrown off my rear alignment, aided in premature tire wear, and may have caused significant rear-end damage.

- Royal Oak, MI, USA

Noticed oil spotting on floor and inspection revealed rear end differential unit was leaking fluid. Dealer found hairline crack and replaced differential.

- Torrance, CA, USA

Excessive wheel hop frequently under mild to heavy acceleration excessive tire wear, tires need to be replaced after 4000 to 6000 miles rear end differential is very weak and may break causing injury or death Cadillac knows of problem providing some customers with extended warranties had a 2004 ctsv and it was lemon lawed in July 2005 for the rear diff breaking 3 times within 1 year.

- Baltimore, MD, USA

Purchased in July 2004. Rear end and differnetial failed at 2700 miles.replaced rear-end. Replaced rear-end agian at less that 7000 miles, replaced tires at 13500miles, rear-end continued to lock and slide tires. Have had car in dealer 5 times and tomorrow, the 3rd rear-end will be put in!!! Cadillac refuses to buy car back but has extended drive train warranty to 100K miles.

- Lewisville, NC, USA

2005, Cadillac Cts-V, wheel hop from rear differential, very common in this vehicle. Cadillac has acknowledged issue by providing extended warranties to "some" owners of vehicles, but not to all owners, rear differential is very weak and may break apart, causing serious injury or death, wheel hop is experienced in my vehicle on a daily basis, original tires lasted less than 6,000 miles, and provided a safety/hazard probelm as manufacturer did not advise consumers that tires would have to be replaced in this time frame, 6,000 miles was a period that most consumers would not consider enough mileage for a tire rotation.

- Coral Springs, FL, USA