Downshift & engine braking in auto tranny Vibe while braking?

[ajf3ajf3]

Nothing regular or recreatable on demand, but this _seems_ to have happened to me a few times in my auto tranny 03 base (had it a couple of months).When going down a hill and applying the brakes moderately to slow down, all of a suddenly I feel a jarring/jerking sensation that would be similar to downshifting in a manual car.It happens so fast that I haven't been able to watch what happens to the tach during it and its not a harsh/jarring jerk, but it is noticable.Didn't know if something like this is normal for the Vibe, or if I should be watching for anything. Seems like it has to be either the tranny, or the calipers grabbing harder at some point.I have 36k on it & it seems to shift normally, otherwise...Thx!

[Baltovibe]

Appears normal ... mine does it also when going downhill. I believe Toyota programmed the auto transmission to downshift when going downhill to help slow the vehicle by use of engine braking.http://forums.genvibe.com/zerothread?id=17562

[Kari]

Quote, originally posted by ajf3ajf3 »When going down a hill and applying the brakes moderately to slow down, all of a suddenly I feel a jarring/jerking sensation that would be similar to downshifting in a manual car.It happens so fast that I haven't been able to watch what happens to the tach during it and its not a harsh/jarring jerk, but it is noticable.Mine does the same thing. I've taken it in to the dealer twice for it and they never could make it do it, so they weren't able to judge whether or not it is normal. This problem is actually the reason I googled "Vibe owners group" and found this site. So I guess in a roundabout way this strange issue has brought me a lot of friends and a future husband. Here is the original thread about it.Sometimes mine is more harsh than others -- it sort of feels like I'm suddenly putting my foot down harder on the brake and then releasing it quickly. That's actually what my mom thought I was doing until I told her it was the car, and that was the problem I was trying to tell the dealership about.The tach does dip down quickly and suddenly when it does this, as I have found one stretch of road where it does it every time, and have been able to watch. Once, it acted like it wanted to quit and the tach nearly went down to 0, but it didn't quit and quickly went back up, so I'm not sure what it was doing.Anyway, mine's been doing it since about 3 or 4K, maybe even earlier. If it is a problem I'd love to get it fixed, but now that I'm dealing with an extended warranty with a deductable, I doubt it will ever get fixed.

[ajf3ajf3]

Thanks guys! A big relief since I just passed 36k (bought it at 35k) and don't have the extended warranty!Still feelin the Vibe

[jasonvibe]

My nearly new '05 does this too. The tranny just knows what speed and load you are at and puts it into gear. Getting off the highway I don't notice it. But on the back roads I do. I don't believe the car knows up from down hill. Maybe something in the manual says? I know some cars have "grade logic". That shifts depend on incline as well as other routine factors.

[mcgusto82]

just think of it as semi auto stick. loli can only imagine how annoying this can be. i usually downshift, but i have the ability to NOT downshift.

[meistees]

my 04 automatic does the same thing while going downhill in the same places around town

[TRDman]

I've got the same thing. My automatic will downshift going down hills (and even when stopping, depending on how hard I hit the brakes); looking at everybody else, it seems normal.

[Toasted7]

My '03 Vibe did that and now so does my '05... is that normal? I think it is really annoying actually. I could fairly easily reproduce it for my dealer if that would get it fixed.

[ColonelPanic]

I haven't noticed whether my new transmission does this or not, probably does, but the original one sure did... Sometimes it was helpful for descending grades, sometimes it was annoying. In general, I find this transmission's "logic" is quite illogical most of the time... I once thought that this was a nifty feature to have, but now I think I'd rather just have it like my old GM automatics where it would sit there and pick up speed as I go down hills and not bother making itself put in any extra work in slowing down the car. That way, I'm putting more wear on one of the least expensive parts of the car, the brakes. And NOT the $4K+ to replace new (thanks, GMPP!) transmission.