MJR Projects

I was having a problem with my Ansmann Mad-Rat (AE B3 knock off) where one wheel was losing traction and spinning when I accelerated fast. So I took it all apart to grease the differential assuming it would be a traditional differential. But when I cracked open the diff it was a ball diff. I went ahead and greased it but now when I try to run the car the motor will spin but the wheels will not move. Now I don’t know what to do except take it all apart and remove the grease. Any suggestions? Should I replace this diff with a traditional diff?

andrewcoley

Sounds like the diff is too loose. You need the grease in there so don’t remove that! (Assuming you’ve put the right stuff in there)

When you took the diff apart did it have a screw through the middle? (It should have had!)

how tight did you do this screw up when you rebuilt the diff?

Jumbo_Jaque

Also, what type of grease did you use? From what I understand, anything other than a grease specifically for ball-diff (usually clear-ish, and will be labeled "Ball Diff Grease", or "Diff Lube") will be too slippery. So you would not want to use a black grease, lithium grease, copper grease, etc. So assuming that the diff was assembled and tightened correctly (although, it does sound like the diff may be too loose), check that you're using the appropriate grease.

motorXhead

iTrader: (7)

like the others said sounds like you just need to tighten the screw that goes through it. be careful not to over tighten it.

MJR Projects

I think that I probably overtightened the diff. The old screw was stripped. I ordered a rebuild kit with a new screw except the new screw was too short. Since this car is old and out of production I can’t find much replacement parts. So now I think I need a new diff. Could you guys provide advice on a replacement diff or a traditional diff?

Btw I used regular white lithium as grease, probably the wrong thing.

Thanks for all you help!

Davidka

iTrader: (86)

Yup, wrong grease. If you use anything other than silicone ball diff grease on the main diff balls it cannot be adjusted tight enough to not slip without seriously damaging the balls and rings, as you just found. Clean out all of the lube and grease the main balls with silicone diff grease. You can use something heavier and more slippery on the thrust assembly. Put it back together, tighten the screw all the way (carefully, only until the spring just bottoms), then back out 1/4 turn. Should be good after that.