: Bucking under deceleration at low RPMs in 2nd gear (automatic) - normal or unusual?



Mr. LCP
08-25-12, 10:18 PM
I had the crazy idea to drive my automatic just like I drove manual transmission cars for 20+ years for a few miles today. In the words of Hank Hill, I can honestly say "that ain't right." Anyway, if I was decelerating with no throttle input in 2nd gear, the car would buck/bog at about every 300-400rpm on the way down once it got below 2500rpm. Now, that SURE didn't feel right. It did it a few repeated times after I noticed it the first time. Is this just normal behavior from the sloppy automatic? Is this symptomatic of a problem? Maybe I should have gotten a manual...not that I'll really drive it this way hardly ever. I tried once to do it in 3rd gear and it didn't repeat. I don't know if I had kept doing it several times if that would have changed.

sykoV
08-26-12, 06:48 AM
We're you at 41 or 42 mph is so that is, Normal. I just got my car tuned for pully upgrade and the difference in the trans shifting is nothing less than amazing.

Mr. LCP
08-26-12, 10:50 AM
It's kind of hard to be at 41 or 42 mph when under 2500rpm in 2nd gear.

baabootoo
08-26-12, 12:17 PM
It doesn't sound normal to me. I'd go back to the dealer. I'm leaving shortly, so I'll try just that.

shchow
08-26-12, 12:38 PM
I drive my auto in the "manual" mode all the time and have not experienced any bucking like you described...

Stillborn
08-26-12, 01:45 PM
no bucking here and i drive manual mode 90% of the time. it didn't do it before the tune or after the tune. something is wrong if it surges at any rpm. could,be low on fluid as some have stated? bring it in to the dealer and take the service manager for a ride, dont let them drive your car. and during the work order make sure you write 'do not drive car.' just my .02

baabootoo
08-26-12, 01:59 PM
Nope, mine was smooth all the way down.

baabootoo
08-26-12, 02:01 PM
Won't they have to drive it before/after the repair? Why is that?

Stillborn
08-27-12, 03:51 PM
driving it would be fine, but those techs bts out of everything they drive. i'll show them the symptom, (via test drive with me driving) then once its fixed ill let them know it's been resolved.

Cadillac Cust Svc
08-27-12, 09:13 PM
Mr. LCP, I too would recommend getting the dealership's technicians to have a look at the "bucking" concern you have. And if you would like me to schedule an appointment for you or follow up with your dealer for you, please email me anytime at Katie_Lucille@gmexpert.com.

Best,

Katie
Cadillac Customer Service

KoNZ
09-01-12, 03:41 AM
Do you have stock wheels and tires?

Mr. LCP
09-01-12, 08:55 PM
Do you have stock wheels and tires?

Yes. Sometimes it was less noticeable or diminished the last several days when I tried to see of exhibited the behavior. It's almost like the car is downshifting even though it is in the same gear the whole time. I wonder if it has something to do with idle control causing the injectors to start firing as rpms get low or something to do with the lockup torque converter.