I've had a problem with my nero big rock since day one with my diff servo, I went onto the discord and asked around and they told me to post here. So my rear diff is making a high pitched hissing sound when engaged and the rear diff won't lock. I took the rear diff apart to see if anything was wrong, nothing was off. I engaged the servo and no noise occured, even the diff locked. However, when I put the thing back together, the problem returned. If you want to add me on discord, I can send you a video of the problem.
Thank you for your time
Thank you for your time