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Dan
Dan, ASE Certified Technician
Category: Cadillac
Satisfied Customers: 1435
Experience:  Dealer Auto Technician
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I have a 2003 Cadillac CTS with 49K mi and automatic

Customer Question

I have a 2003 Cadillac CTS with 49K mi and automatic transmission that whines intermittently after shifting from 3rd to 4th and into OD (5th). I've taken it in to 2 Cadillac dealerships and as many transmission shops and nobody has been able to pinpoint the source of the whine. I've had the fluid drained and replaced along with the filter, the EPC solenoid replaced and the TCM replaced. The vehicle has not and is not displaying any DTCs relating to the transmission or otherwise. Driving symptoms: From a cold start the transmission shifts normally for the 1st 1-2 miles then starts to whine after shifting from 3rd to 4th and into OD (5th). The whining will continue for the next 5-15 miles and then disappears when the vehicle is completely warm. When I shift the car into neutral while the car is moving (and whining) the noise disappears. The whining is most noticeable under slight acceleration or deceleration (under hard acceleration it disappears). The pitch of the whine is pretty consistent (doesn't change at lower speeds) and at high speed (over 60 mph) the noise diminishes. These symptoms have been confirmed by the technicians that have been trying to diagnose the problem. My question is whether or not the problem could stem from a bad transmission temperature sensor or connection since the whine only occurs when the car is cold.
Submitted: 6 months ago.
Category: Cadillac
Expert:  Dan replied 6 months ago.

Hello, my name is***** can help you on this.

Usually a whine in the transmission is the pump. The fluid will be thicker when cold. Verify fluid level in the transmission, if too high or low it will cause the pump to whine.

Make sure it's not a power steering pump, or alternator whine. If the power steering lines are leaking it could be, drawing air in causing a whine.

Customer: replied 6 months ago.
Your answer is pretty generic. The whine is definitely in the transmission...I mentioned that when I drive the vehicle when it is whining and shift into neutral the whining stops. I also mentioned that one of the shops I took it to changed the fluid and the filter. I trust that they refilled the transmission to the proper level. Also there was no change in the amount of whining afterwards. My question to you was whether a bad temperature sensor could cause the pump to whine because when the car/transmission comes up to normal operating temperature the whining stops.
Expert:  Dan replied 6 months ago.

If the temp sensor was bad, it would set a code, not cause pump to whine. Double check fluid level, your vehicle does not have a dipstick so there is a procedure that needs to be followed. When trans fluid reaches operating temp it expands, causing level to rise. I would bet your trans fluid is low. Not saying your shop made a mistake, but things happen.

2003 Cadillac CTS V6-3.2L VIN N

AUTOMATIC TRANSMISSION FLUID LEVEL CHECKING PROCEDURE

Start the engine and allow the engine to idle until the transmission fluid normal operating temperature has been reached.Depress the brake pedal and move the shift lever through the gear ranges, pausing a few seconds in each range. Return the shift lever to the PARK range.Raise the vehicle on a hoist. The vehicle must be level, with the engine running and the shift lever in the PARK range.CAUTION: The engine must be running when the transmission fluid fill plug is removed, or excessive fluid loss will occur. Transmission fluid may be hot. Since the actual fluid level is unknown, stand clear when removing the fill plug. Have a container ready to capture any lost fluid. Do not turn the engine off with the fill plug removed, as you can be injured by hot transmission fluid being expelled out of the oil fill opening.

Customer: replied 6 months ago.
I'm not very optimistic that this is the problem but I'll give it a try. Since it is the weekend I'll have to wait until Monday to take it into a shop. I'll keep you updated. If they didn't follow the procedure exactly as outlined when they replaced the fluid what actually occurs within the transmission to cause the level to drop? Bubbles? Change in the level of the fluid in the transmission when the engine is running vs. not running?
Expert:  Dan replied 6 months ago.

Yes, the level changes with heat expansion and contraction, if not properly filled, yes it could have air in the system cause the level to drop. If it is overfilled, it will turn the fluid foamy also could cause the pump to whine. Checking the fluid level is the easiest thing do, always start with the basics. Keep me posted on what you find. This is a sort of hard problem to diagnose over the computer, without me being able to drive the car, feel and listen.

I have been researching this problem and found a few TSB's related to whine noises.

When you bring it into the shop ask them to check for bulletins for this problem.

Yes keep me posted on what you find. Have a great weekend!

Customer: replied 6 months ago.
I have access to the TSBs provided by alldatadiy.com. Can you give me the number, date and title of the ones to which you are referring?
Expert:  Dan replied 6 months ago.

One was related to the rear end, the other I saw was related to the engine balancer pulley. There is another one for a bearing inside the transmission. I will get you the numbers and dates.

Expert:  Dan replied 5 months ago.

Do you have any updates on the car? Did you end up taking it in?

Customer: replied 5 months ago.
Printed out the check auto trans level instructions and took it in to the shop. There was also a TSB from 2004 stating the fluid temp had to be within a certain range when checking the level otherwise it "might raise customer concerns"? Anyway they checked it and said the level was OK. I also had them change the oil in the rear end with a type that had the GM additive already mixed in because it also had a faint whine between 35-50 mph (notorious for this vehicle). It didn't eliminate the whine completely but it's not as noticeable. Really frustrated with the transmission whine because one, it's annoying and 2, nobody can seem to pinpoint the problem. Just to refresh your memory if you'd like to research the problem a little more: The car has 49k miles on it. It was owned by an elderly couple who did regular maintenance on it and I don't imagine drove it very hard. The car starts up fine shifts into gear (reverse and drive) fine and shifts through the gears fine until after 1-2 miles at which time the transmission starts making a whining noise after shifting from third to fourth with a chirp and then into fifth. The whine is most noticeable between the speeds of 40-50 mph above which the volume tapers off. The whine is the loudest during deceleration or coasting. The pitch of the whine is usually the same irregardless of speed. The whine can be eliminated by 1. shifting into neutral, 2. pressing on the brake or pressing on the brake while keeping your foot on the accelerator and 3. hard acceleration. After driving the car for 10-15 miles and the vehicle has warmed completely the whining stops. Turning off the traction control, putting the car into the sport mode or the winter driving mode has no effect on the whine. I've had the transmission control module, the EPC solenoid and the transmission filter and fluid replaced. The vehicle is not registering any DTCs. Two other items of note are that the auto trans was designed to shift like a manual shift (see TSB) and it has an engine braking system that is controlled by the transmission. Thanks for your time and effort.