Auto Trans acting weird

[Mario]

Am I the only one to experience this with my car?

At exactly 50KM/H (31.25Miles/Hr), while coasting at steady speed, the transmission is hunting gears between the 3rd-4th speed and the downshift from 4 to 3 is kinda hard, like getting hit from behind. Over 55KM/H, no more problems. (Don't tell me it's the solution... I've got police cars that triggers really easy in the neighborhood...)

My car will be meeting the dealer for this, probaly, as I don't think this is a normal behavior.

To avoid this, I have to select "3" when doing city driving.

2005 Chevy Optra Wagon (Forenza's twin)
Only 2500KMs!

[Tim04]

I've never noticed that with my auto tranny. That sounds like a job for the dealer.

[MMamdouh]

i don't have auto tranny but that doesn't seem normal at all.

MMamdouh

[damian007vk]

yeah, have them check it out....does it also happen harshly when you place your car on reverse? if so, they might also wanna take a look at your map sensor, which believe it not i have seen cause that same problem...or you might not have enough tranny fluid, or the line pressure might be too high....but yeah, the car has warranty, have the dealer worry about figuring it out.

[TheGreatAndPowerfulOz]

Have you been feeding the hamsters that power your car as often as needed?
If not, they may be running out of energy before the transmission shifts; that would cause the harsh shifting.



LOL


Yes, it sounds like the dealer needs the car back to have a complete inspection, adjustment and/or repair as needed.


Cliff

[Mario]

Thanks for the replies...

I'll see my dealer for this, but probably not for another 2-3 weeks. 2500KM is way too soon for my 1st oil change. Until then, we'll drive it on "3" while driving in the city, that way I won't fear screwing anything.

Just by curiosity, is there a way I can check for the automatic-oil level on these cars? Manual only says to have a dealer check it if we think we're low on it. There is no dipstick for it that I'm aware of.

[Mario]

I finally had my dealer check on this. At 1st, they couln'd reproduce the problem, but OBDII scanning (via TECH 2) while I was driving showed that the car was in fact really hunting gears between 3-4 at 51KM/Hr. It also showed that the Lockup converted was engaged/disengaged a lot while coasting at that precise speed (That's their explanation for the jerkiness).

Reflashing the trans computer with a newer calibration helped a bit, but didn't not fully solved my issue. (was described as "Improving Shifting Performance" in the version log).

A call from the tech to GM Canada headquarters confirmed that I was the 3rd to report similar issues, but that they think it performs as it is designed to. There answer for now is to avoid coasting at that speed or select "3" while city driving.

I'm only 50% satisfied with that answer, so I'll probably have them check again for updates on that case in 6 months...

[lanos2001]

more than likely if they've (GM canada) have already gotten a few other calls your probably looking at a recall within the next 6 months to a year for it.

nick

[Mario]

I'm not sure it would qualofy for a recall... after all it isn't safety related. I would expect them to release a TSB on a to fix it tought, and my guess is, it could be as simple as another calibration firmware.

[Mario]

Another update on this:

GM finally managed to solve the problem with another recent computer calibration. Seems that it was supposed to be aimed at cars that get a service light and get stuck in 4th gear, but it also solved my gear hunting problem aroung 50Km/h

Calibration was released on June 23rd 2005... according to the tech.

Just wanted to let you know if somebody else wanted to get their car fixed for this.