"Bump" at stoplights feels like changing gears

bkoeth · Post by **bkoeth** » 30 Aug 2007, 02:41

1997 850T5 auto.

Every once in a while, when I am sitting at a stoplight for a while (trans in D, brake pedal pressed), I feel a 'bump' that I can only describe as feeling like changing gears. It's only happened twice, but that's twice in two weeks. Had the car more than two years, one year on this transmission, never felt it before.

It's substantial enough for passengers to notice, but not catastrophic. It's noticeable, but doesn't make me spill my coffee or anything. Feels like the 2-3 shift in ECON, except the car is sitting perfectly still. Anyone else ever get this? What gives?

Post by **JRL** » 30 Aug 2007, 05:38

The first thing to do is look at the trnasmission fluid, but regardless, change it and go from there

phoenix_iii · Post by **phoenix_iii** » 30 Aug 2007, 08:02

Does it happen just as you are coming to a stop, like when the car would want to downshift into first (or slightly after), or are you STOPPED at the light for a good 10-15 seconds or +, and THEN you get a bump?

bkoeth · Post by **bkoeth** » 31 Aug 2007, 02:46

The two times it's happened, it's been after 15-30 seconds of sitting still.

Post by **pfeener** » 31 Aug 2007, 07:11

It could be just the engine stumbling a little at idle. My 98 S70 has done a similar thing since it was new. The first few times it did it when I was at a light, I looked in the rear view mirror because it felt like someone had tapped my bumper.