Walaikum Assalam,
First of all check temp needle when idle. Temp needle does't have any link to gear or transmission.
Do you have t-stat installed? If yes, then it is normal unless needle got over 70%.
T-stat valve is there to keep engine at optimum temperature. When you start your engine at cold, t-stat valve is in close position so the engine can warm up quickly and needle start to rise up. When engine gets its optimum temperature, t-stat valve goes open and you can see temp needle drops down to normal position i.e: 30 - 40%.