i have a 99 z28 with an a4, the trans is having some serious issues, in 3/4 it acts as if it is slipping or a super high stall speed. it constantly acts as if it wants to downshift.. if you pull it into 2nd it is a non issue whatsoever, now here is the tricky part i guess, if you go w.o.t it is fine, and once your into a higher mph range it is not there, say around 55-60 mph, even if your 75% throttle like coming onto an on ramp it is fine, its only when just cruising around town from light to light...if you fight throught it ,eventually sometimes it will kick down and actually go..any things to try or check here, before i stick a fork in it? hope im not confusing you guys as i am confusing myself, please help..xmas is the wrong time for this to go south, especially after i just order all sorts of other goodies.. the car currently is all stock except for a slp lid/bellow/fliter ,thanks

 

How many miles and whats the fluid condition?

 

122k and fluid is still colored (not like new but there is a tint of red) doesnt seem to smell burnt, i was considering a fluid/filter change.. we deleted the a/c and some other odds and ends, then this started, i feel it is coincidence, i cant recall anything we did in the process that would effect it... it works great if you stay w.o.t, dont want to spend alot of cash with it as im planning on a fully built deal summer 2009..thanks for the reply

 

Can you tell whether it's converter unlock vs other
frictions slipping? Any access to a scan tool?

 

see it almost seems as it is converter unlocking, but the best way to descibe it was in the o.p .. yes i got access to a scan tool, wasnt kicking any check engine lights , so looked directly passed that....ill have it scanned

 

If you can see input & output shaft speeds in the
scan tool, and dump that to Excel, you can tell if
there is slip in the "gearbox". TCC Slip RPM will show
if the converter is unlocked or flaring. TCC Mode
will show you the intended state.