Broken rear diff the third time
I’m facing a serious problem about my SUMMIT’s rear differential. It was broken the third time now. I really don’t drive very aggressive or do something like bashing with it. I just installed a mid range BL system made by KD (850W). I investigated that the problem is always about the ring gear and the pinion gear inside the differential. While driving first a clicking noise appears. If I continue driving the tops of the tooth of the gears will be sheared-off.
The first time I faced this problem it was caused by a broken bearing inside the differential housing that pivots the pinion gear. Thereby it could slip back some small tenth of a millimeter so that the gears did not mesh properly anymore. Substituting the bearings with a full metal one solved that problem for now. Anyway I had to substitute the complete differential housing because the broken bearing and the tooth parts were scattered all around the housings.
But after repairing the differential was broken again a similar way. This time the substituted bearing is well but the ring gear was loosen from the inner differential housing (5681) because the threads were destroyed. Again the meshing between ring gear and pinion gear was out of order and the tops of the tooth of the gears were sheared-off. So I replaced all the parts again, as it were a complete new differential (including the full metal bearing).
Not fine again! This time I stopped driving the second I realized the first small clicking noise. The noise tells me that the meshing is bad again. What could the reason be? Is the differential housing (5680) deforming itself by a power of 850W? Or is the differential carrier (5681) to weak?
Now I think about installing the rear differential from a brushless E-REVO to my SUMMIT. It should stand the power of 2200W. Sure with this I can’t lock the rear differential anymore but an unlockable diff is worth more than an broken one. Does anybody know about a suitable differential made of metal?
Thanks for your answers!
shimming the rear diff/how 2 test?
Thanks again Guys!
Iím afraid this would have been my next question. Iím afraid I didnít understand every term quite correct. Maybe itís because my bad English. :(
Since I donít have any shims jet I only can care about the inner diff parts. I never thought there would be a need to shim the spider gears. But there is, as I realized while demounting it again.
I mounted the inner diff parts (5681) very carefully and exactly like it is shown in the drawings by TRAXXAS. Still without any shims but using the diff oil offered by TRAXXAS. Here is the next problem: The completely mounted inner differential is very hard to turn with your hands. Maybe itís also because the diff oil comes with a pretty high viscosity. But you can feel every single teeth while turning the differential outputs. Is this normal?? [B]sfr4x4 [/B]wrote ď[FONT="Courier New"]until I can just feel an occasional very slight bind on one or two gear teeth per revolution as I turn the gear[/FONT]Ē. Does that mean it should feel really smooth-running except some very small bugs once per revolution? My diff is really hard to turn with the hands and you can feel every single teeth. How could this be and what should it feels like? Pleas advice!! :confused:
How to keep the ring gear scrwes tighten
Yes, I checked that first, because it happens to me before. But the pinion bearing is ok. I discovered, that the screws of the ring gear became lose again. So the 3rd case in this graphic happens to me again. [IMG]http://www.vecto.net/tmp/pix/diff01.jpg[/IMG]
Additionally I installed one more shim on the pinion gear. That feels good so far, but while driving the 3rd set of batteries the clicking noise appears again. What now?
Again checking the diff and discovered that the 4 screws on the ring gear became loose again. (!!!) Just after one hour of driving. How do you manage to keep the screws tighten? Using locktite should be a solution. But we are talking about a differential which is full of oil. When you mount the ring gear the excessive diff oil will leak thru the four holes. No locktite will bond here.
Here is my idea:
1. Mounting the (inner) diff normal using diff oil. All of the parts are oiled now.
2. Then loosen just one screw and clean it up using a fat solvent fluid.
3. Cleaning up the free hole in the ring gear and its close area using a fat solvent fluid.
4. Wait until the fat solving fluid has vaporized.
5. Reinstall the screw using lockite.
Do this to all four screws one by one, while all other screws are tighten.
I did so. Letís see if it survives now.