Fuzzy logic on AT transmission?

[bellwilliam]

I am wondering about the smartness of the AT transmission.this last weekend, I took a trip to death valley. while traveling through at least 10 different mountains, I notice 2 things with this automatic transmission.1. while going downhill, AT holds lower gear smartly for engine braking. I tried to trick the AT to upshift, but it wouldn't as long as I was on a decline.2. while going uphill, AT also hold the lower gear. I did not have to turn off the overdrive at all.I haven't owned much AT cars, mostly manuals. I didn't remember automatic transmission being this smart. I have a 2002 Chevy Venture Van, its AT is nowhere as smart, if often hunts for gear. Did AT got really good this past few years, or did the heat of death valley clouded my head?Death Valley is really nice this time of the year. temperature averaged 76 degree. Vibe also hit 115mph on the straight. I also got 28mpg during the return trip. 28mpg is the best I've gotten so far, I usually average 24mpg.p.s. I was putting in gas in Death Vally, it was $2.65 per gallon !!! I was parked next to a Chevy Suburban. I put in $20 or so, Chevy was hitting over $80, and was still going when I left. I could see the guy's envy at my Vibe then.

[Stang2Vibe]

Wow, that's a lot for gas. Filling both tanks on that Suburban must cost a small fortune.As for the tranny, many newer trannies are getting pretty good. My mom's 1996 Saturn SL2's transmission ran very much like you describe when it was switched into performance mode. The Vibe's auto tranny may have a gravity switch or something like it to sense the amount of incline/decline the car is on and use the data from the computer regarding speed, throttle demand, current gear, etc. to determine shift points or what gear to be in at what time. Pretty high tech stuff to be able to coordinate it all.

[Flip-Side]

quote:As for the tranny, many newer trannies are getting pretty good. My mom's 1996 Saturn SL2's transmission ran very much like you describe when it was switched into performance mode. My trips home take me through mountains, and like BellWilliam says, it does a good job finding the sweet spots on grades. I also had a 1992 Saturn SL2, which also worked impressively, even compared to some automatics today. It was important for me to get an auto that would not do any "hunting", since it was a problem in my Chevy S-10, and Buick Park Avenue. Also, I miss that Normal/Performance switch in my Saturn. It was nice to be able to change the attitude of shifting for the situation at hand.

[Jethro]

I plan on having my dealer look at my AT specifically because of the "hunting" for gears when going up and down frequent hills. I'm thinking that the (IMHO) poor performance of the AT is at part to blame for the mileage being less than what it's rated at.Good to hear others are pleased.

[drb22]

keep us posted on what the dealer tells tells you, as I would sure like a better milage, if possible.

[ColonelPanic]

Did you ever find anything out about your transmission? Hopefully it will be a simple fix, such as reporgramming the computer or something.I'm wondering if these transmissions have adaptive logic, where they learn your driving habits and shift accordingly... When my Vibe was new, it never quite knew what gear to be in - especially when in city driving. At 5,000 miles, it seems to have cleared up. I'm wondering if the car has adjusted its behavior to match mine, or vice versa?

[fire_502]

When my Vibe was brand new, I never noticed anything weird about hot it shifted. When I got up to a couple thousand miles, I started feeling it shift harder. I do a lot of city driving, and I notice it most when I'm just coasting. As soon as I apply the gas again, it will give a little jerk before it goes. It does not do it every time and I know I am not slamming on the gas, so I don't know what the deal is. It also downshifts noticeably when I come to the top of a hill (even just small inclines like the kind RR tracks are on sometimes.) I took it back to the dealer last week and the service manager told me that they didn't find anything wrong with it. So I told him I'd be back if it gets worse.Does it sound bad because it was not doing this when it was brand new, but kind of grew into it in a couple thousand miles? I only have about 3400 miles on it now, so I guess it's possible it still could adjust, but I'm not sure. Should I take it to a different dealer? Any suggestions?

[fire_502]

I don't know, regular little hills....like stupid, man-made, concrete no-apparent-purpose-serving hills. Would it make a difference if I said I work in Auburn Hills? It's slightly more hilly there...maybe. It's in the name at least. Cut me some slack. Maybe this is part of my problem...I got my car in Richmond. Maybe that's why the dealer said he has never heard this kind of comment before....because it's all flat out there!

[FOCthS 83]

quote:p.s. I was putting in gas in Death Vally, it was $2.65 per gallon !!! I was parked next to a Chevy Suburban. I put in $20 or so, Chevy was hitting over $80, and was still going when I left. I could see the guy's envy at my Vibe then.thats exactly why my dad is looking into the vibe. he has a '96 tahoe and he was looking @ the avalanche but want to get good gas milage like i do in my focus.

[fire_502]

Nope, it's Shadow. And I don't really go out that direction all that often anyway. They had to find one from another dealer to get me the color and options I wanted. Anyway, they do suck because when I got it, they didn't know how to program the remote keyless entry and I had to bring it back when they could call the help line. They have done a couple other stupid things that annoyed me too, but this bit with the guy telling me it's new and I probably just have to get used to it kind of pissed me off. Anyway, yeah, when I hit the gas it delays, jerks, then goes. It just does not seem to be this fabulous, smooth transmission people claim it is. My rpms don't jump high unless I'm flooring it to pass or something (but it also jerks when I do that). Otherwise, they just go up a little until I hit the right gear. It's not making any strange noises or anything, and I'm not leaking anything, and there aren't any weird odors or anything. Just the jerk. I am kind of used to it now, but I don't want to let it go if there is a problem and end up having an even biger problem later.

[pmh013]

Apparently the Vibe "learns" your driving habits, and puts the tranny in whatever gear it thinks it needs to keep the emissions down. (This is according to the service manager at the latest dealership I've been dealing with)I can commiserate with the shifting thing. I would have them check the catalytic converter. Note that the dealer will need to have parts in stock to do so, because you've gotta take the thing half apart to do the test, and they wreck a gasket in the process. I've got a cat on order, because they are suspecting mine is plugged (hence all the trouble I had back in the cold weather).Unless you are having serious gear-hunting (like downshifting while going downhill or on flat, which happened to me) you will get told that the car is operating normally. Even still, they tell you that the car is operating normally

[ragingfish]

quote:Does it sound bad because it was not doing this when it was brand new, but kind of grew into it in a couple thousand miles? I only have about 3400 miles on it now, so I guess it's possible it still could adjust, but I'm not sure. Should I take it to a different dealer? Any suggestions?I've had similar problems with every car I've ever owned. I always was under the impression I drive SO hard, and really work the tranny, that I've just messed them up. My biggest problem is when I slow down on the highway to go through the electronic toll lanes, when I try to speed up again, the car just goes so slow, it's the equivalent of accelearating from a stop in 5th gear on a stick. It just takes so damn long, I have to downshift and force the AT into a lower gear. When I talked to the dealer, he said the tranny probably just hasn't caught up yet. I dunno -- I've always been disappointed with teh response time of my ATs...but because I don't know how to use a manual, I've always had to buy an auto.Any thoughts anyone?

[ColonelPanic]

quote:Anyway, yeah, when I hit the gas it delays, jerks, then goes.I believe there was a TSB regarding rough shifting and incorrect fluid being used. In your case, do you think it would be a possibility that somewhere along the line Dexron was added instead of the Toyota fluid these transmissions require? Perhaps when the vehicle was delivered it could have been a little low, and they added Dexron, not knowing... Not sure how rough a little bit of Dexron thrown into the mix would make it though, and I doubt they had to add much (if any at all) but just another thought.

[NSimkins]

quote:I believe there was a TSB regarding rough shifting and incorrect fluid being used.FYI, here is the TSB you are referring to:http://www.nhtsa.dot.gov/TSBScans/sb629810.pdf -- second paragraph

[fire_502]

That sounds like it could be my problem. I have never added any fluid myself, but maybe the dealer did and put the wrong one in. It was acting a little better yesterday, but started again today. So since there is probably no way of telling what's in there, would the dealer change it if I brought this up?

[ragingfish]

I would like to get my fluid checked too, or rather changed...but frankly, I know the dealer's gonna say "we put the right stuff in, trust me." And I'd go to Toyota, but prolly pay out the (removed) to have it changed...grrrr....