dimitrios wrote:1) Can it be that the wheels lock because of using other than Nissan CVT Transmission fluid?
Possibly.
Quote »2) Or because there is no oil cooler present? (but car doesnt heat up that fast from starting and trying).[/quote]If you are referring to the oil cooler that is normally located in front of the rad, you should be fine without it.
Quote »3) Do we really have to buy another transmission or could we just flush and try with the Nissan cvt fluid? (Nissan Mech says transmission is contaminated and needs to be replaced)[/quote]Nissan will not cover any transmission issues unless genuine Nissan CVT fluid is used. You have basically voided the warranty for the transmission now. Nissan CVT fluid is specially formulated to allow the CVT belt to work properly and prevent transmission wear. AFAIK, there is NO substitute for it on the market.
You can try to flush the transmission using new CVT fluid. Worst case, the transmission may eventually fail. With some luck, you might get it working for awhile.
My next best guess for brakes locking up is a defective master cylinder or brake booster. An improperly adjusted M/C will cause the brakes to be applied prematurely.This may not show any DTC codes either.