Transmission Tick Flutter Noise at Highway Speed - 07 & 08 DTS

Tomko · #1 (**permalink**) 05-11-08, 09:40 AM

This just in from General Motors:

"On some 2007-08 Cadillac DTS vehicles equipped with 4T80E MH1 transmission, a ticking/fluttering noise can be heard in the vehicle at highway speed.

The noise is generated by the modulation of the TCC solenoid. Movement within the solenoid excites the shift cable, resulting in a low level, high frequency noise that can be heard in the passenger compartment

To correct the condition, install a solid lead clamp mass damper to the cable. This has been shown to significantly reduce or eliminate the noise."

If you have this condition, you may want to print this out and bring it to your dealer.

TulsaVic · #2 (**permalink**) 05-11-08, 05:33 PM

Don't notice a noise but am debating whether or not I should complain about abrupt shifting ( 1st - 2nd) with my '08 Performance. Moderate to quick accels from a stop produce a quick, smooth shift. Same if I gradually keep on depressing the gas pedal. But gentle throttle--a "grandma" accel if you wish--will result in an almost neck jerking upshift.

dtson22z · #3 (**permalink**) 05-12-08, 10:58 PM

same funny up shifting with my 07 dts. If i drive agressive i dont feel it but if i drive like my grandma i feel it quite a bit. Bothers me a little. Took it to the local dealer and they told me that if nothing comes up on the DIC they wont even know where 2 start the diagnostic. GO figure

caddycruiser · #4 (**permalink**) 05-13-08, 09:01 AM

Most of that, as far as how the shifts feel and when they do so is all in the programming...so unless there's a new or revised transmission program out, it would be hard or impossible for them to "find" any issue. Shift placement and feel is all based on throttle position and a few other factors, hence why likely--even if it doesn't seem right--that you're getting snapped when babying it and otherwise fine.

Could be a programming flub from the start (rare, but it happens), meant to be like that completely, or some other kind of an issue. Unless GM releases an updated transmission flash, it's something to get used to--OR keep complaining about it, and the more GM gets feedback, an actual response might come.

Otherwise...as for this TSB on a noise, good info.

nosro · #5 (**permalink**) 05-13-08, 10:13 PM

Thank you! This had been driving me crazy for a while. I thought it was the engine, but this makes more sense.

The dealer did note that many DTS's had this problem but they had no service bulletin, until now.

nosro · #6 (**permalink**) 05-13-08, 10:16 PM

Quote:

Originally Posted by TulsaVic

Don't notice a noise but am debating whether or not I should complain about abrupt shifting ( 1st - 2nd) with my '08 Performance. ...

The TCC solenoid is not directly involved with shifting gears. The TCC handles torque converter lockup.

I hear you about the shift quality though. The 1-2 shift is always the most difficult for engineers, but you'd think they would have this figured out by now for an ancient 4-speed design.