Shift points

[Steve_NC]

The dealer told me that the MM "learns" how we drive, and will change the way the tranny shifts. Is this true?, and if so will disconnecting the battery for a few min reset these "learned" shift points? I love the car and driving it is a dream, but it shifts all over the place. I have to turn the OD off when I am in town. The constant shifting thru all 4 gears makes me nuts. I want to do a retune and a chip, but the cash isnt there for that just yet.

[jstevens]

Steve, I think the dealer is feeding you some bs. The tranny does learn to shift somewhat but the only real fix I know of is the chip.

And just shutting off OD around town.

[Joe Walsh]

It is REALLY annoying how our transmissions are programmed to jump into 'OD' as soon as possible, which makes driving around town totally annoying.
I am sure this was done to get better fuel economy, but our DOHCs don't like grunting along at 1600 rpm trying to pull 4400 lbs of 4 door sedan.
I used to drive with the 'OD' off to keep my sanity until I had my Marauder tuned with 'OD' locked out until @52 mph.

[ckadiddle]

The custom tunes purchased from our supporting vendors will take care of the annoying shift habits at low speeds. Makes the car a whole lot more pleasant fun to drive. Also adds a few horsies.

[SergntMac]

Adaptive Learning is a feature of the on-board computer system. It records most recent engine behavior and operating conditions, and refers to that data when making decisions about air fuel ratios, spark, timing advance, ect. This is why engines tends to misbehave briefly, when they have been dormant over a period of time where there has been a change in the weather. This is also why it's the occassional WOT down an on-ramp is a healthy thing.

Yes, you can clear it by disconnecting the battery, but it will rebuild a new memory as you drive on from there. And yes again, you can shut it off, but I would expect this to result in more "every once in a while" type disturbances. Overall (and IMHO) Adaptive Learning is a good thing, but you have to teach it how you drive.

Recording transmission shift points, i.e. line pressure, shifting by speed, or, RPM and so on, and changing them on the fly, well, that's news to me. The only signal the PCM monitors is tranny temp, and that's to decide if the appropriate "cold start-open loop" schedule is in order (TC will not lock-up in open loop). Adding a chip/flash tuning will make changes to the shift schedule, but these are hard program changes and considered "permanent" as opposed to how Adaptive Learning functions.

Out of the big red book, the OEM shift schedule for the R470W, with 3:55 gears in place. Sorry, I don't have specs on the 4W75W tranny.

Light throttle upshift...1>2 @ 6-9 MPH, 2>3 @16-18 MPH, 3>4 (OD) @ 28-31 MPH.

Closed throttle downshifting...4>3 @23-27 MPH, 3>2 @13-17 MPH, 2>1 @ 8-12 mph.

WOT throttle upshifting...1>2 @ 37-42 MPH, 2>3 @69-73 MPH, 3>4 (OD) @ 65 MPH

Forced downshifting (passing gear) 3>2 @ 65 MPH, 2-1 @ 31 MPH

This schedule can (and usually is) adjusted to speeds more "sporty" by aftermarket tunes. But, you need to be careful with what you ask for. A while back, Lidio tuned my car and spent considerable time test driving the shift schedule on the street. He did a great job on this and the car handled great. But, once I returned home, I had difficulty in adapting his schedule to my driving habits on the roads (and at the speeds) I travel everyday. A few tweaks here and there improved my control of shifting by throttle, and I picked up some MPG in city driving as well.

I am sure there is more I do not know about this, just adding what I do understand.

[MitchB]

The trans control has no adaptive capability at all. It does what you tell it to do, nothing more. You make a very good point about regarding your tuning experience. A few things like trans shifting is so very dependant on the user's preferences that I do not see how it is possible to tune someone's car remotely. I spent many hours datalogging my car's performance with subsequentally changes along the way.

Mitch


Adaptive Learning is a feature of the on-board computer system. It records most recent engine behavior and operating conditions, and refers to that data when making decisions about air fuel ratios, spark, timing advance, ect. This is why engines tends to misbehave briefly, when they have been dormant over a period of time where there has been a change in the weather. This is also why it's the occassional WOT down an on-ramp is a healthy thing.

Yes, you can clear it by disconnecting the battery, but it will rebuild a new memory as you drive on from there. And yes again, you can shut it off, but I would expect this to result in more "every once in a while" type disturbances. Overall (and IMHO) Adaptive Learning is a good thing, but you have to teach it how you drive.

Recording transmission shift points, i.e. line pressure, shifting by speed, or, RPM and so on, and changing them on the fly, well, that's news to me. The only signal the PCM monitors is tranny temp, and that's to decide if the appropriate "cold start-open loop" schedule is in order (TC will not lock-up in open loop). Adding a chip/flash tuning will make changes to the shift schedule, but these are hard program changes and considered "permanent" as opposed to how Adaptive Learning functions.

Out of the big red book, the OEM shift schedule for the R470W, with 3:55 gears in place. Sorry, I don't have specs on the 4W75W tranny.

Light throttle upshift...1>2 @ 6-9 MPH, 2>3 @16-18 MPH, 3>4 (OD) @ 28-31 MPH.

Closed throttle downshifting...4>3 @23-27 MPH, 3>2 @13-17 MPH, 2>1 @ 8-12 mph.

WOT throttle upshifting...1>2 @ 37-42 MPH, 2>3 @69-73 MPH, 3>4 (OD) @ 65 MPH

Forced downshifting (passing gear) 3>2 @ 65 MPH, 2-1 @ 31 MPH

This schedule can (and usually is) adjusted to speeds more "sporty" by aftermarket tunes. But, you need to be careful with what you ask for. A while back, Lidio tuned my car and spent considerable time test driving the shift schedule on the street. He did a great job on this and the car handled great. But, once I returned home, I had difficulty in adapting his schedule to my driving habits on the roads (and at the speeds) I travel everyday. A few tweaks here and there improved my control of shifting by throttle, and I picked up some MPG in city driving as well.

I am sure there is more I do not know about this, just adding what I do understand.