My Associated T3 RTR doesn’t accelerate forward the way it used to. When I give it throttle, it moves, but something seems to be slipping and a terrible noise is coming from my truck. My friends told me that the slipper clutch or ball differential may be loose. How do I tell which one is causing the problem?
If you encounter this issue, stop driving immediately, and take your truck to the pits, as driving under these conditions will put a ton of wear on whatever component is slipping and the parts will need to be replaced. The good news is that this problem is easy to diagnose without having to tear apart the transmission. The first indicator is sound; a loose slipper clutch usually makes a “smooth” whirring sound — it doesn’t usually sound like something bad is happening. A slipping ball differential, however, usually makes a metallic screech that sounds “wrong.” To confirm which component is slipping, remove the gear cover so you can see the slipper clutch adjusting nut. Hold the rear tires and apply the throttle until the motor spins the spur gear. If the adjusting nut doesn’t spin while the gear turns, then the clutch is slipping—tighten the nut a turn at a time until it no longer slips under hard acceleration. If the adjusting nut spins with the spur gear, it means the differential is slipping. You may be able to simply tighten the differential by turning the adjustment screw in the outdrive (see your manual), but if it’s been slipping for a while, or the diff has gone a long time without maintenance, a rebuild is in order. Sounds like a slipping diff to us, and since your T3 is an older truck, a rebuild with fresh rings, balls, and thrust bearing is the way to go. The part numbers are in your manual (No manual? Download a PDF at teamassociated.com)
In a 2WD electric model, drivetrain slip is typically caused by the differential (left) or slipper clutch (right).
The nut on top of the spring is the key to diagnosing a slip problem. If the nut spins with the spur gear, the diff is slipping. If the nut doesn’t spin, the slipper clutch is slipping.