GeeWings 2829 Posted September 6, 2021 So, I started the build of my Rere Egress yesterday. Haven't got far at all, just mounted the motor and got the Diff build going. Now, it's been a very long time since I last built a car but the Diff has me slightly worried! I built and then tightened so the spur gear doesn't move then released as instructed. The Diff seems to be working i.e. if I hold both outdrives the diff gear can't move and If I turn an outdrive the other moves in the opposite rotation. But, it has an almost gritty feel. Its this normal? I'm wondering if I should take apart, clean, re-grease and put together again. Share this post Link to post Share on other sites
Champ85 608 Posted September 6, 2021 Well-adjusted ball diffs have a somewhat "gritty" feel to them when turning one outdrive (and the opposite outdrive spins in the opposite direction). It's hard to put into words, but the "gritty feel" is like what you would imagine "white noise" or "light roughness" would feel like in terms of smoothness as you spin the outdrive. It's not a silky or slick grease smooth feeling like you would expect from perfectly round steel balls and flat washers with grease between them. Spinning one outdrive should offer some resistance to turning, but not a lot. Locking the outdrives should not let you spin the diff gear easily. If your diff feels like this, then it's normal. From your description, yours seems to be correctly adjusted. But if the diff feels hard to turn one outdrive and when it does finally start to turn it feels like too-tight meshed gears turning, like a "ribbed" or "hard bump" or "notchy" feel to the rotation, then it means the diff is too tight. If you are still not sure, the best advice I can give is to gain some experience of how a ball diff feels when it is loose, correctly adjusted and too tight. Start from too loose: Loosen the diff screw all the way and spin the outdrive and feel how silky smooth it is (if it's really loose, then the opposite outdrive may not even spin at all). Tighten the diff a little bit. Spin the outdrive again. Feel how it spins with more resistance from the diff "tightness". Keep going. Tighten a little bit more (Once it starts to feel "gritty", just turn the screw 1/8th of a turn each time - it doesn't take much to go from "just right" to "too tight") and spin again. Feel it. Tighten again. Keep doing that over and over and you will start to understand how a ball diff feels when it is too loose, when it is adjusted just right, and when it is too tight. The point is to make it so the diff gear is mostly locked when both outdrives are locked, but the diff gear will give way if enough torque is applied. If it's too loose, the diff gear will spin the balls but not the outdrives and generate heat which can damage the diff gear. A ball diff is not a slipper. If it's too tight, it will be too "locked" and not act like a differential should (and have that ribbed, notchy feeling when turning an outdrive), plus it can damage the balls or diff washers over time. 2 Share this post Link to post Share on other sites
GeeWings 2829 Posted September 6, 2021 Thanks @Champ85 Yes, hard to explain as you say but it feels almost like consistent, smooth, grit! My sense is it's probably fine but I will play with loosening to get a feel. Thanks again. Share this post Link to post Share on other sites
Rb4276 803 Posted September 6, 2021 Also with the egress and avante black ball diffs they basically have to be fully tightened Share this post Link to post Share on other sites