Thanks. I have checked out the other threads.
RAV4 transmission trouble is quite common (unfortunately I found out after experiencing the problem). Apparently the ECM installed in these cars is faulty and after about 60,000 miles it fails and damages the transmission. Signs to look out for are the consistent check engine light coming on,gears shifting erratically and at times the car jerks or simply slows down to a near stop before picking up speed again.
I have since changed the transmission but I am not putting the car back on the road as that would be a death wish. Anyone with a RAV4 for 2001- 2003 should be on the look out for these signs unfortunately it also occurs without the check engine light coming on and you will only realise when the transmission is damaged.
The car was shifting from 4th gear to 2nd,it could revv at about 4,000 RPM while at 30Km per hour!! The worst bit was slowing down to a near stop before picking up speed again.
To realise the magnitude of the problem just 'google' RAV4 transmission trouble.