91 q45 trans help please

[revhead]

Hi guys im new here and ill post pics of my beast as soon as i work out how lol,its low on coilovers running 18s,dark tint,dyno tuned 245kw
auto on the beast feels great but when i put it in first or second it wont compression down,goes in smoothly if i touch throttle but if i take off throttle falls out of gear.
shifts great up through gears and fluid clean and unburnt.
any ideas appreciated.

[qship96]

compression down? What are you attempting to communicate to us?

[Lokim]

I think he's saying it won't engine brake. What speed are you downshifting at? If you're downshifting at to high of a speed, the transmission won't go into a lower gear so you don't over-rev the engine.

[revhead]

yeah sorry thats a better description of problem it wont engine brake.
Wont engine break at any speed,starts off in first if I put it into first as it should but if I release throttle drops into neutral???

[maxnix]

ATF white paper towel test? Maintenance history?

[revhead]

Yeah done that fluid is clean,not brown or burnt smelling.
I dont have much history on maintenance but car is in top cond for age and auto feels great unless trying to engine brake.
Could it be vacuum or tps sensor related? The tps sensor went on a jeep i had and that 'fell' out of gear.

[Infinitiguy19]

Does the "TRANSMISSION MALFUNCTION" message come up in the screen that says "OK" every time you close the door?