j-boy

Wow... funny you should mention this problem because I have been experiencing the same thing. And both sets of diffs do it so I think the cast was alittle off when they were makin em. I ended up grinding a few teeth on the out put shaft a little wider BETWEENthe teeth. I worked on this for days and finally figured out that I had to rotate the center output shaft around till the diff "hung up" and then lift the top off and pull the diff itself out while not moving the output shaft. I then reached in with a sharpy marker and marked the teeth that were at the bump spot. It was hard to tell which one of the teeth it was for sure so I marked like three teeth right there and worked on those teeth. Iknew it was one of them cause after they were marked Icould put everything back together and it would allways hang up at the marked teeth. I determined that it was the center output gear because it was the only part that allways rotated around 1 time and hung up at the same spot. Have you noticed that you can set the two halves of the diff case together without any screws and they will rotate just fine? I f they do you can squeeze down on the side that the big gear is on and they should cause the bump problem. Also remember almost no differential can be tightened down real tight. or it will cause binding. Just snug up the screws holding the case together and it will turn easier.

Anyway after I figured out that it must be the center output gear teeth I got my file out and started working on them. I knew Ineeded to be real carefull here cause removing too much material would result in a stripped gear. But after a couple of hours worth of filing wiyh no positive results I resorted to my dremel tool. I assumed the problem would be one of the points but rounding them off (I did all three) didn't help any. I then grinded just a little off of the ridges of the teeth but this didn't seem to help either. I eventually got around to removing some metal from the SIDES of the gear teeth and although I still can feel a tight spot It is a lot better than it was. Anyhoo you can try this or not it's up to you but please be carefull not to remove any more metal than is absolutely necassary. I have not run my revo since I made this mod so I can't even be sure that the diff is still going to hold up. Anyway I have been having heat issues so I was checking for binding and things like that when I found the diff problem. This is what I came up with and like I said... take it or leave it, it's up to you. Just please be carefull if you break out the high speed rotary tools on your diffs! lol