First of all, why would your TnG card 'going' to expire soon ?

As far as I know, TnG card will still be active if you use it once in a year.

And yeah, it's possible to transfer the credits to your bank account, not sure for different card.

Yes, can transfer the money from your existing TnG to your new TnG but there is transaction fee, and one more thing, make sure you are the owner of that card (meaning that the card is registered to your name). I think you need to go to one of the outlet (not the Plus outlet but TnG). Did that few years back.
TnG card has 10 years lifespan (expired at the 10 year), happened to me earlier when i complained that my card has like RM 200+ but cannot use. You can check the expiry date from Plus or the self service kiosk which can reload TnG

Oh wow since 2006 ...... how is that even possible good job

to transfer credit back to bank account , u have to go to any toll plaza beside any highway. Then proceed from there. I think they charge around RM5.30 for deactivation.

Not sure much bout the details, you can ask sifu-sifu sekalian di atas yg posted

Btw bro, should go and check if there are any rebates in your 2006 card since it's been accumulating for so many years.

Rebate them and transfer the credits to your new card if possible

even if got rebates also, must've already expired 

actually i have one tng card dated 2003 but i am still using it. lol...