lexixel

Hello,

My car with A650E (5 speed) has a couple of shifting behaviors that I suspect aren't normal:

1. When going uphill at speed and the car has downshifted to 4th, once it has got too fast or I've reached the top of the hill I would reduce the throttle angle, and after a few seconds sometimes the transmission would shift into 5th quite hard. If I lift off completely, the transmission just goes into 5th immediately (normal). It seems that the ECM locks 5th out, and once it allows 5th again if the throttle is at certain angle it would launch into 5th.

2. When going downhill and tapped on the brake and the car has downshifted to 4th for engine braking, similar things happen: If I accelerate hard, it stays in 4th and later upshifts fine. If I accelerate very lightly or tap the brake again it would go into 5th fine. But at certain throttle angle it launches.

3. In traffic jams, I think it hunts 2nd gear (and maybe 3rd) --- very, very light tap on the throttle would cause it to downshift and it upshifts after lifting off the throttle.

4. (maybe normal) If I use the shifter to lock out some gears (e.g. in 4 to lock out 5h), and then move the shifter up, if the car upshifts under power it would launch like 1 & 2. This is true for all shifter positions.

Anyone has experienced similar shifting behaviors? I think 1, 2, and 4 are probably related.

Thanks

Bgw70

and how many miles and has the transmission fluid ever been changed, how many times?

lexixel

110k miles,
fluid changed at 32k & 68k (simple drain & refill) before I got it at 100k
I changed twice; oil pan was replaced at the dealer
I bought an electric fluid pump and changed it 5 more times since. Now it has 117k.

Fluid level is good. Shifting is normal. I think it's more an electronic issue.

Bgw70

did it begin all at once or after a visit to your mechanic?
what type of fluid did you or your mechanic use?

117k miles is very low for a transmission to go out. Do you drive it hard?

lexixel

Fluid used always T4 / 3309. First two services were at the dealer.

Symptoms 3 & 4 has always been the case. 1 & 2 I just noticed in March. It doesn't happen unless there's a long incline that necessitates a downshift.

I don't drive it hard, but don't know how it was driven before. I mostly take it on 100+ mile drives. Done a few 300+ trips this year already. During an eight-hour drive, it didn't do 1 & 2 because the road was quite flat.

Come to think of it, I once noticed the transmission do another stupid thing when cold: on a descent I accelerated a little; then the light turned red and I lifted off. It just upshifted before I lifted off, and I could tell it downshifted quickly when I lifted off.

I'm asking here because it feels like the computer is stupid more than other things. If this doesn't happen on other cars, then something is probably wrong with mine.

Bgw70

Actually, most of what you describe kind of seems normal. Not all of it but most seems normal.
i think I would almost need to see what it is doing to properly determine if my car does the same thing.

is there any chance you could make a video and post it to YouTube?

lexixel

Hi, thanks. It wouldn't be possible to make a video for 1, 2, & 4 because only my butt could tell when the car does that

When it does 1 & 4 it feels like a poor / hard shift, but there's no surging of the engine (like when it's slipping - I had that on another car that blew the transmission, so I frequently look at the tach when I suspect it might do something like 1). But even though there's no surge, the feeling is somewhat similar to when you shift very quickly on a manual.

With 4, it's very different from tiptronic type of shifting which would just bring the rev down smoothly. But it's not very noticeable unless I pay attention to it. It also feels like when you run over some rough roads.

When it does 3, I think the engine goes to maybe 1000-1100 rpm and because I'm just barely touching the pedal, it upshifts and the engine is at 800 rpm and then it thinks maybe it's good to downshift. Usually, after this it knows to stay in the lower gear. However, usually at some point a few meters / yards down I brake, maybe stop. Then this happens again. I think it also happens to 2nd-3rd. Maybe I'll make a video about this.

Thanks

Coleroad

Is there a TSB on this? Sounds like could be something that a transmission reprogramming might be called for. In ZF transmissions, you get this kind of behavior when the trans solenoids are going out. The other thing, is some of what you're feeling the torque converter locking and unlocking and not really a shift?

lexixel

Hi, I seem to remember that this transmission can only lock the TC in 5th gear. I think it locks & unlocks fine. There's usually just a 200 rpm drop when locking.

Could be the solenoids, yes. Maybe TPS, too.

ShawnOk

iTrader: (1)

Could it be speed sensor? I had similar problems on my 1999 Chrysler Sebring (Automatic) as it was failing. Then when it finally crapped out, it wouldn't shift out of first gear.

lexixel

I noticed one thing that could be causing no.3:

With the key on without touching the pedal, the throttle position is read at 17%; once I touch the pedal and release it, it goes to 13%.

I read somewhere that the good reading should be 15% and 12%. I managed to get 13 through 21%, so I think the TPS works. Unfortunately, I was unable to loosen the lower screw for adjustment. This probably requires throttle body removal.

lexixel

Good news: I cleaned the MAF and the car no longer does 1, 2, 4.

3 is less noticeable. Maybe it needs TPS adjustment that I couldn't do.

lexixel

Uploaded a video on 3: