Trans Or Tune? Need Help

[RB_GURL]

I have a Rb20de auto skyline. Im not sure if it needs to be tuned or if my trans is screwed, as the

car can drive but it isnt driving properly. When i accelerate the revs

go up slowly to about 3-3.5 then they shoot up to about 5 and then the

car starts to move faster. It also doesnt change gears until about

40kmph.

[mystery_kid]

sounds like a slipping auto