Occasionally, the transmission in my 2004 Olds Bravada makes a 'rattle' sound for 1/2 to 2 seconds just before upshifting from 2-3 (and maybe also from 1-2). I hear the rattling begin as the RPMs increase just before the shift is commanded and the rattle ends instantly when the shift completes.
Wondering if anyone else has experienced this, and maybe fixed it? Any ideas what it might be?
Thanks in advance!
- There are no negative symptoms associated i.e. no slipping, no 'end bump', etc, just a highly unnerving rattling sound.
- The problem started around 80K and the truck now has 98K miles on it.
- Never happens when manually up-shifting, even if I delay until several hundred rpms past the normal shift point.
- Happens more when tranny is hot -- don't think I've ever heard it with a cold tranny. A few hours towing a 2,000 lb trailer is sure to provoke it, but it does happen without towing,
- My Tech2 does not indicate any issues or transmission codes.
- Complete tranny flush/fill done at GM @ about 90K miles -- this had no effect on the rattling behavior.
Wondering if anyone else has experienced this, and maybe fixed it? Any ideas what it might be?
Thanks in advance!