My Cirrus steering servo recently died on my E Truggy so I borrowed the steering servo along with arm from my nitro truggy. The steering servo and aluminum servo arm worked flawlessly for months on my nitro truggy but now that its on my e truggy its having this issue after two batteries, the aluminum servo arm doesn't spin when the servo spins. It seems like now the servo arm is too big for the splines on the servo. How could this happen when it was just working strong on my nitro truggy?
I'm using a Hitec 645MG if that helps

Did you move the servo horn along with the servo, or move the servo and try to reuse the horn on the first vehicle? I'm not familiar with those brands, not sure how many teeth each one require for the horn... someone else will probably chime in with that. Always start with the obvious, horns are not always interchangeable. If you did move the servo horn with the servo as it sounds, you may have just stripped a gear inside the servo.. that's the other most obvious thing to check.

I swapped the horn with the servo from my nitro truggy. The wheels sometimes turn when the car is off the ground but only to one direction. The servo does turn right to left when the servo horn isn't on.
Thanks

Which piece would strip first, the spline on the servo nose or the grooves in the servo horn?
I bought an Airtronics 94358 for my E truggy Friday and a AIR specific horn but will keep Hitecs in the N truggy. I'm trying to determine though if the servo horn stripped or if the splines on the servo stripped.

Sounds like the splines in the arm are stripped. I had that happen this weekend in a race. I all of a sudden couldn't steer but when there was no pressure on the wheels it steered find. Cost me the main

Thank you sir. That's the same conclusion I came to after inspecting both clearly. Well it lasted almost a whole year so I guess I can't complain.