Shifts getting less firm after long drives
12-15-2009, 08:14 PM
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Shifts getting less firm after long drives My 2000 A4 Formula has an issues with shifts getting less firm after relatively long drives such as > 30min or so. Is my transmission getting ready to 
? When the engine is cold, it shifts perfect. The longer I drive, the worse it gets. It doesn't seem to be slipping at all, just pretty sluggish when shifting. I checked the fluid last week, and it was a bit low, so I added some but I didn't overfill it. What's up with this?
? When the engine is cold, it shifts perfect. The longer I drive, the worse it gets. It doesn't seem to be slipping at all, just pretty sluggish when shifting. I checked the fluid last week, and it was a bit low, so I added some but I didn't overfill it. What's up with this? 
12-16-2009, 04:55 PM
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TTT again. Basically, it shifts strong then it gets lazy taking entirely too long to shift. It does make the shift, but it takes too long.
FLT, Performabuilt, any advice?
FLT, Performabuilt, any advice?
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12-17-2009, 09:25 AM
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There are tables in the tune file which change the force
motor current based on trans fluid temp. Maybe you want
a trans cooler. Especially if you are also running stock
fan settings, which will let the coolant run up way hotter
than it should (trans can be no colder than the radiator).
PCS valve is the "force motor" and may just be doing what
it's told. If you get the tranny cooler on there and it's still
fading, then think about sticking your fingers in the guts.
motor current based on trans fluid temp. Maybe you want
a trans cooler. Especially if you are also running stock
fan settings, which will let the coolant run up way hotter
than it should (trans can be no colder than the radiator).
PCS valve is the "force motor" and may just be doing what
it's told. If you get the tranny cooler on there and it's still
fading, then think about sticking your fingers in the guts.
12-17-2009, 03:47 PM
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Thanks for that suggestion! I will certainly look into it. I may be imagining a problem when there isn't one. Wouldn't be the first time 
.
It seems less to do with transmission fluid temp, although that could have something to do with it, but more of an issue of driving time. For example, even after it cools down, if it has been driven, it seems less firm. Hmmmm. Interesting!
. It seems less to do with transmission fluid temp, although that could have something to do with it, but more of an issue of driving time. For example, even after it cools down, if it has been driven, it seems less firm. Hmmmm. Interesting!
12-18-2009, 10:17 AM
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There are also "shift adaptation" strategies at play
which dial back the pressures to barely achieve the
shift duration targets set up in some shift-time tables.
These can be pretty soft / leisurely in the stock tune.
The question there would be, why was it ever good
to begin with? I don't know whether it starts from
zero or keeps a running tab across key cycles. I zero
all this out first thing, so that it can't steal back line
pressure after I get things tweaked to suit.
which dial back the pressures to barely achieve the
shift duration targets set up in some shift-time tables.
These can be pretty soft / leisurely in the stock tune.
The question there would be, why was it ever good
to begin with? I don't know whether it starts from
zero or keeps a running tab across key cycles. I zero
all this out first thing, so that it can't steal back line
pressure after I get things tweaked to suit.
