Auto revving to 5000revs before changing gear

you need to change the oil in the auto box. if this dont help then the servo in the auto box is sticking.

run fault codes and look for TCM and other electronic problems in the transmission.

too heavy a motor oil can cause hard shifting also,but when its cold out let your car warm up longer before you take off,it might help

i take it this is when your on the road doing some sort of speed or is it at rest and just revving up?... any changes made to car in the past?.. is it when you turn ect.... give as much info as poss,
my club

First, make sure your airfilter is not plugged. If it is, the engine is compensating for the lack of air intake. If not, consider replacing the Idle Control Valve. Inquire with an auto parts dealer (store) for this part.
Please let me know if you need further assistance.
carsandcomps,
Guru, Premium Expert @ Fixya.com

No not at all, no damage to the transmission will occur. Just watch your revs and that you are not over-revving the engine. The hold function is incorporated into a transmission to allow you to hold that gear selected. This is most useful for when towing a heavy load down a hill, The transmission will hold that selected gear, preventing the car from changing gears and "running away". Basically allowing the engine braking being to be more effecient and the driver not having to ride the brakes as much, therefore reducing wear in the brake system. ;-)

the clutch is slipping and needs replacing

The forester diesel 6spd gear box is designed to replace the high low gear box so although starting off in second or third gear is possible .... puts a lot of strain on compents ie clutch/ gear box . very slow manuovering is much better carried out in 1st gear , as is moving from stationary . The engine torque is low dow the rev range high max idle is reached very quickly . The diesel engine characteristics are different to the petrol version ( I own 2.5 forester 2009 - 7.8l per km's @55000 km's). So you need to change your driving style to suit . I have test driven the 2.0l Diesel and sufficiently impressed to replace the 2009 version with the diesel .

sounds like its not going back into first gear at the lights then it kicks back when you take off,but it takes off in second,get the adjustments looked at as you could damage it if you keep driving it,its cheaper to do a small fix than wait and have to do a major one,bite the bullet and get it looked at soon

Sounds like warped fly wheel.