Hey guys, am trying to work out what the problem is with this transmission,it was good when I gave the car to my dad,but developed this problem a while back,car drives great when it's cold and even at operating temperature but after a drive and turn it off-if it's driven again whilst it's still heat soaked it starts acting strange like it's slipping but feels different to what it should be doing if box is worn old and slipping,my dad got a transmission Service done on it but it's still doing the same thing may even be a little worse now,I don't think it was flushed out at all and have no idea what trans fluid they put in it,am trying to check fluid level but they have over tightened the filler plug,anyway just wanted to ask if anyone has any idea what might be going on.
When it does play up you put your foot down and sometimes it may work after a few seconds and sometimes it's like the power it not being transferred through the box to the driveline,just doesn't feel like it's slipping in the traditional sense,lol me so confused

if it was good before .. but not now - findout what fluid etc was actually used/done.