Originally Posted by
aus jd 2703
hey guys i got a slight problem
i just rebuilt my diff, didnt touch the thrust bearing just cleaned the diff balls and relubed, i actually loosened it this time compared to wat it was, and i like to run lots of diff lube so the action of the diff is stiff and slow, but when i checked to see how tight it was it didnt slip like normal it clicked? any idea what this is? it was chucky and clickedas it slipped in chunks not smooth like normal,
i continued to break it in and after i rann it the click seems to be gone any idea's what i may have done wrong?
also does any one make dust shields for the rear diff?
and what servo savers fit the mi3 i think i need one?
cheers
The first thing you shouldn't have done was not touch the thrust. IMO, when a diff goes out, the thrust is the problem 90% of the time. The second thing is that you don't want to use a lot of diff lube. Lube isn't there to give a smooth diff action. That's what the balls are for. The lube is there simply to cool the balls so they don't over heat. I don't put any lube on the rings at all. I just put some diff lube on the tip of my finger and thumb, pick up the ball with it off a clean shop towel, and roll it round in the lube. Then drop it into the pulley. That's all the diff lube you need. More lube just makes the diff slip more, creating more heat, and attracting more dust and dirt. There's really no need for dust shields if the diff is built right.
The two most important things are to make sure everything is clean, and that you don't get any black thrust grease (even possible contaminated residue on your fingers) on the main balls or rings. I use gloves (to keep the oils from my skin from contaminating the rings and balls), a lot of motor spray, and about 20 minutes to build a diff now. And they turn out great and last a long time if you take the time to do it right the first time. (I just put the first new diff in my car since the Reedy Race last May.) Whatever you do, when you build a diff, build the whole thing. Not just balls and rings. The chunky clicking you're feeling is probably the thrust full of dirt and gunk. If I were you, I'd get new balls (not the ceramic, get the carbide. They work better) new rings, and a new thrust just in case you damaged anything. Make sure you sand both sides of the rings using an old thrust side out drive, a flat surface, and some 600 grit, wet dry sand paper with motor spray on it to make sure they're flat on both sides. The small grooves the sanding leaves will also give the diff balls some more traction on the rings and keep the diff from slipping with a looser setting. Also make sure that you look at the rings profile. One side will be rounded where it was stamped out and one side will be more square. Make sure you put the square edge against the outdrive. It'll hold better to the outdrive and keep it from shifting. Also, make sure you get the older Mi2 rings, not the Mi3 rings. The Mi3 rings with the key on them can cause problems by not letting the ring slip a little if you get a funky side load on the diff. Like when you ride up a curb similar to the Tamiya track.
Adrian posted a step by step a while back. Find it and follow it to a T.
As for a servo saver, if you have a metal gear servo, just use the plastic horn that comes with the car. It's going to strip out before the metal gears are going to.