7AT Problem?
 

I purchased my '12 Z almost two months ago and ever since the first day I purchased the car, whenever I brake hard I feel a "thump" in the transmission as my speed decreases. I did a search and found that some 7AT have hard 3rd-2nd shifting and/or 2nd to 1st. Is this what I'm experiencing? If I brake softly then it doesn't do it. Its as if the transmission mounts are loose or something. Please help

Ask the dealer, it's under warranty.

Mine does this occasionally, computers fuggs up and downshifts to fast.

The problem is that mine does it every time unless I brake slowly. If it were to do it every once in a while then I can live with it but not every time. Can anyone else that has a 7AT please tell me if this is normal. Thanks!

Sounds like ABS. How hard are you braking? Is it sport pkg or regular?

Slightly clunky downshifting into lower gears on decel is normal... mine does that quite a bit, especially after manually operating the gears (the ECU learns your shift patterns, and "replays" them in regular auto mode.)

Unless you are hearing an audible "thump" or it's tooth rattlingly harsh, it's probably normal.

Still, if unsure, no harm in having the dealer check it out -- warranty!

I have the sport pkg but I have never manually shifted. Maybe manually shifting for a while will help the ecu? I don't really hear any noise just feel the car jerk forward as I brake down to about 20-15mph. But like I said only when braking hard...don't feel it while braking really slowly.

I mean if you are going to brake hard. The car is going to lean a little. As far as the sound. When a car is brand new, sometimes the brakes are a little noisy as they need to break in as well. The noises could come from the pads & rotors making contact when braking hard or the ABS? Your descriptions are not very good so its really hard to understand what you mean. But if I had to guess? Its just break in sounds from you braking too hard. Over time the brakes will smoothen out.

Sorry guys if I'm not explaining myself correctly. I believe jordo! Has it right its clunky downshifting. Its coming from the transmission not the brakes 100% sure. I'm not braking extremely hard either since the car only has 800 miles. I'm just frustrated because I just bought a $30,000 car and it feels like it has bad engine or transmission mounts. Its not noises I hear its a jerk forward.

I have the same "problem" It took me a while to figure it out. If you want to visually see what I am talking about, whenever you are coming to a stop shift over to manual mode and watch the gear number light. The little thump you feel is when you are coming to a stop and the car shifts from second to first. A good bit of times, it is a pretty good jerk. I believe, but not for sure, that the connection from first gear to second gear is different than the connections from 2-7. That is why I just ignore it and try to not let it bother me anymore.

Mine does this also once in a while it kind of bangs downshifting to 3-2 but mostly from 2-1.

I have the same situation. Sometimes the ecu is faster to the down shift in manual mode then I am so it feels like we had a split second disagreement but the ecu wins every time. For me I found slowing earlier and smoothing out the distance to stop in lower gears helps.

I have to say I kinda love the feeling it reminds me I am not in a sedan :)

Thanks jpritche you're absolutely right. I went out this morning and put it in manual mode while braking and the "jerk" that I feel is the shift from 2-1. I feel sooooo much better...thought something was wrong with my car. Thanks everybody for the input and help!

That's called DOWNSHIFT REV MATCH brother. What's being called a bump is your DRM is always active on manual mode. Its there so when you are on a highway, you can get an extremely fast throttle response when downshifting on the accelerator. When you downshift, say to a stop sign, you will feel the same thing. Under decel that would be called engine braking. There's nothing wrong with the car. If you don't want to feel it. Keep the car in D and only shift when you need to. Then let auto mode downshift for you.

:iagree: