I was given 2 nitro trucks i think they r both tmaxx 2.5 wit the 3 channel 2215 27 mhz am receiver 1 sanwa mx-3 came with them can it be used for the truck.This is my first nitro so i could really use some help please.Thanks in advance fellows.

in short, yes that TX can work with the trucks, but that TX will not work with those RX installed on the trucks. to get that controller to work in those trucks you will need to get a receiver compatible with your TX.
is your MX-3 the 75mhz version or the 2.4ghz? if it is a 75mhz (crystals) version i would highly suggest getting a 2.4ghz radio system, if yours is the 2.4ghz version i would try to find a compatible receiver.
if yours is the 75mhz version or if it is difficult to find a receiver compatible with the 2.4ghz may look into this radio system:
44$ GT3C (has a rechargeable battery)
https://www.amazon.com/FS-GT3C-3Channel-Transmitter-FS-GR3E-Receiver/dp/B07C9ZGMG9/ref=asc_df_B07C9ZGMG9/?tag=hyprod-20&linkCode=df0&hvadid=312184153387&hvpos=1o1&hvne tw=g&hvrand=12238139512768525796&hvpone=&hvptwo=&h vqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9021359 &hvtargid=aud-829758849484la-569828763097&psc=1
37$ GT3B (uses 8 AA batteries.)
https://www.amazon.com/GT3B-2-4G-Fly...WAXXVX1MYHKH6Y

i have a nitro rustler and when i drive it after about 5 minutes the steering goes out and does not work but the throttle still work is it a bad steering servo or what could be wrong

Check the servo connector from the servo for corrosion. If it’s clean, try another servo. When the steering servo stops working, try plugging the throttle servo into the steering channel on the receiver and see if it works. If it does, then the servo is bad.

Thanks for the information I have the same problem