rev problems

[TronsBird]

at idle my car revs fine, i can take to redline while in neutral
but, when driving, it will get to about 3k or 40mph, then the revs bounce and it cant go any higher

its like its cold and its very cold out
but that isnt the issue

trans problem?
plugs and wires?
old gas?
carb?

its been sitting since the summer i assume

[TronsBird]

ive looked around on the internet and people who have similar problems say its the valvebody or fluid, ive noticed since i bought it the trans leaks a little, i know its been sitting for a while , so im hoping its just low on trans fluid

[NJSPEEDER]

Please don't take your engine to redline in neutral, you will blow the rings out of it and wreck the engine.