2004-2007 Cadillac CTS-V General Discussion Discussion, Is my gear whine normal? in Cadillac CTS-V Series Forum - 2004 - 2007; I know the whine is common, but is mine louder than it should be? Car has 23000 on it, and ...
Though it was tough to hear properly, to me it sounded like a hum that I have, too, and it's not like diff whine. Kinda thought it was the new 275 GSD3s I just put on the back since it's proportional to vehicle speed and independent of gear,clutch in/out, etc, but I'm not certain of it being tires. Bought some lithium grease spray for the driveshaft bearing thinking that might help, but haven't put it on yet. Too blasted hot out. Very noticeable today to the point where I thought my wife was going to comment on it, but no ... thank goodness.
Going away with application of throttle or letting up on the throttle would seem indicate that whatever's making the noise gets thrust to one side and doesn't then have an audible component.
I would change the fluid as already suggested, but would also take a close look at the old fluid. If the old fluid is visibly full of metal that is clue. While I generally agree with the "drive it until it breaks" approach, there is some risk. Specifically, if this is an original 2005 differential it may "break" by grenading, which is common to the first generation units. If it grenades at the wrong time, such as during a high-speed pass in the rain, the result could be worse than just a broken part.
I thought maybe tires, it was awfully low pitch to be the diff, but still possible depending on recording device.
He didn't give a great description of when he hears it in relation to on/off throttle, thats the key..
Cupped tires can fool you with minor changes in speed, especially low speeds.. but even then, due to the drivetrain slack, you can usually trigger/release diff whine and the pitch while maintaining a constant speed.
The best test imo is 4th gear, decel with foot off throttle from 50 to 45. Or, 50-60 accelerating...
Sounds like my rear diff, but man your interior is quiet.
I have studio monitors hooked up to my desktop, and I think I could hear it as a diff whine.
I wouldn't get hopes up of a fluid change getting rid of it. My diff whines in 4/5 with very slight throttle input or cruising, but it hasn't gotten too much worse in the two years I had my V. Today I swapped my diff fluid w/ Royal purple, some 140wt, some 90wt, and it seems about the same. I had a slight coating of metal sludge on the plug. It didn't seem to be an unusual amount.
Add a catback or full exhaust and you won't care about the diff sound any more.
I'd complain and see what the dealer will do? Worth a shot, at least. Wouldn't be surprised if the new one whined, too, but at least it would be the newest generation so more durable.
If it goes away on acceleration and deceleration, and also happens at the same rpm's in any gear, I'd say it's highly likely to be your differential and it's not likely something you've gotta worry about. Just keep an ear out for it getting louder. To be sure it's the diff, drive around with your rear seats folded down. If it's louder with the seats down, then it's definitely coming from the diff.
I know its the diff, as I know what gear whine is. I had a bad set up on an 89 mustang that whined. I was more concerned with whether it was to loud. It whines at the same rpm in each gear it whines and I can control the pitch with throttle, to include maknig it stop completely. I'll change the fluid and let it ride. I dont drive the car hard, thats what my lightning is for.