Occasional harsh downshift on auto

[Ribfeast]

Hi guys,
Just having some issues with my auto (minor I hope).

I have an A341LE (30/41LE) auto transmission in my 1JZ cressy. Running Toyota Type IV fluid, tranny cooler, fluid is in excellent condition.

If I give the car a hard time (i.e. floor it for a bit, then slow down for the lights) it will often downshift really harshly into 1st (or maybe 2nd, whatever it sits in when you are at the lights).

It feels like you have just changed down a gear and then let the clutch out too fast in a manual car.

Car has a stage 1 shift kit from MV automatics, however it did this before the shift kit went in too.

There is a slight kink in one of the metal fluid lines near the box but from what I can see it should not impede flow much, but would fluid starvation cause this at all?

Should I be concerned at all? It rarely does it when driving gently, or if it does, its to a lesser extent.

Another thing I noticed is that when the car is cold and I turn overdrive off, it feels like it is trying to go into 4th when I hit around 70kph, even though the ECU is stopping it. This problem goes away when the temp gauge hits normal operating temperature. Any ideas?

Thanks for any help

[1JZ.747]

check your fluid levels.

adjust your kick back cable.

[Vios-GT_07]

if it doesn't come standard with a tranny cooler i wouldn't put it in unless it's got a thermostat to control heat..

tranny fluid is supposed to get to operational temp via the radiator.. however in motorsports they use tranny coolers for high-powered applications but it still maintains operational temp.. seen this happen in a cresida b4 as well where the guy had a tranny cooler then few months down the track the box shat itself.. wan't a 1JZ though

[Ribfeast]

The tranny cooler is before the radiator, so even if it overcools, the radiator will heat it back up to its right temp before going back to the box. It does this harsh shift regardless of the temperature.
I adjusted the kickdown cable to no effect.
Might add some more fluid tonight, it already sits on the top of the 'hot' section when I check the levels after a long drive though (checked with engine running).

If the fluid is low maybe it is being sucked into the torque converter and away from other areas when I give it a hard time? And then its got nothing to cushion the downshift with afterwards? Still doesn't explain why it only does it on 2->1 though

[1JZ.747]

you can move the kick back cable quite a bit which will change the shift form haser to softer as it raises or reduces the line pressure on the box. this will also give you a fraction more stall as well.

this may be part of it it may not be.

[Ribfeast]

I had the kickdown set really soft a few weeks ago, and I adjusted it for a harsher shift not long ago. But this funny downshift has been happening since I got the box last year, I think there's something stuffed inside it Just gotta work out if its something easy or something expensive.
I was hoping someone had experienced the same thing and might know what it was, Mike at MV had no idea when I asked him