Radiolink RC4GS V3 5 Channels RC Transmitter and Receiver, 2.4GHz Surface Remote Controller R6FG Gyro RX Combo, 30 Models Storage for RC Crawler, Drifting, Bash, Buggy Cars and Boats

This would work fine https://a.co/d/04S8XTlW

First, charge the batteries and test again. You said you drove it for 20-30 minutes. Start there. What you’re describing is low voltage cut out. Bumping the voltage to 8.4v is going to drain the battery faster than 6v. It’s not just the servo getting that voltage, the fans get it too. I recently rebuilt my Xmaxx and put in the Max5/1100kv motor, PP monster t servo, and swapped out the receiver because everything I read said not to take the Traxxas receiver past 7.4v. If the batteries are good, take it back to 6v to test, if it still doesn’t work, swap the receiver. I bought this one: Radiolink RC4GS V3 5 Channels RC... https://www.amazon.com/dp/B07DPMVVKN?ref=ppx_pop_mob_ap_share