18Likes"How To Properly Build And Break In a Ball Differential and Slipper Clutch"
04-08-2013, 12:03 PM
#301
Hi guys,
I am hoping someone will be able to help me with a problem I have.
Firstly, thank you to Racer 53 for your diff rebuild videos. They are excellent. I've subscribed to your channel.
I've just gotten back into RC after a 25 year break. To get back in I bought a T4 second hand. The owner told me he had just re-built the diff.
When it arrived I fitted the electronics and went for a drive. It turns out the diff had never been set.
So I set about stripping out the gearbox as the diff was built with the cover over the head of the thrust bolt, which I removed then re-assembled. I then followed the videos to set the diff. I just could not get it right. It would be fine a few minutes, then loosen right up. After a few re-tightens I realised I had the diff the wrong way round (head of the bolt was on the left, looking. From the rear).
I then stripped the entire thing and re-built it as per the videos.
I struggled quite a bit with getting it right in terms of how tight and I think I was virtually at the bottom of the spring. If I look at the plastic T nut holder for the thrust bolt it seemed like it was really being pulled concave a bit. But if I put screwdriver shafts to hold the diff outdrives (outdrives?), if I really twisted hard I could move the diff, but only just and I really had to twist hard. I backed off the bolt a little bit, then re-assembled everything (the right way round this time).
I then set about doing the run-in. As I was getting to the end of this I heard a pop and saw the T nut holder had shot out and hit the dogbone (this was the pop sound). I opened up the opposite side where I saw the head of the thrust bolt had snapped off.
So, I started again from the beginning, went through everything as above. I ended up getting the same result only this time a little further into run-in.
There was another symptom I noticed. When the gearbox was assembled but out the car, when I twirled the shaft that the slipper and spur attach to it wasn't completely smooth. It felt like every 1-2 turns there was some imperfection that the gears had to roll over. I can't see this affecting the diff, although I don't know enough to tell.
I'm a bit at my wits end. I don't know what I'm doing wrong. My sense of it is I'm over-tightening the thrust bolt and the pressure is simply ripping the head off.
I'm now out of thrust bolts so will have to get more.
Are there any pointers anyone could suggest. I really want to get this right.
Maybe I should start with a really loose diff then tighten up? I think I'm starting too tight.
Thanks for the help.
I am hoping someone will be able to help me with a problem I have.
Firstly, thank you to Racer 53 for your diff rebuild videos. They are excellent. I've subscribed to your channel.
I've just gotten back into RC after a 25 year break. To get back in I bought a T4 second hand. The owner told me he had just re-built the diff.
When it arrived I fitted the electronics and went for a drive. It turns out the diff had never been set.
So I set about stripping out the gearbox as the diff was built with the cover over the head of the thrust bolt, which I removed then re-assembled. I then followed the videos to set the diff. I just could not get it right. It would be fine a few minutes, then loosen right up. After a few re-tightens I realised I had the diff the wrong way round (head of the bolt was on the left, looking. From the rear).
I then stripped the entire thing and re-built it as per the videos.
I struggled quite a bit with getting it right in terms of how tight and I think I was virtually at the bottom of the spring. If I look at the plastic T nut holder for the thrust bolt it seemed like it was really being pulled concave a bit. But if I put screwdriver shafts to hold the diff outdrives (outdrives?), if I really twisted hard I could move the diff, but only just and I really had to twist hard. I backed off the bolt a little bit, then re-assembled everything (the right way round this time).
I then set about doing the run-in. As I was getting to the end of this I heard a pop and saw the T nut holder had shot out and hit the dogbone (this was the pop sound). I opened up the opposite side where I saw the head of the thrust bolt had snapped off.
So, I started again from the beginning, went through everything as above. I ended up getting the same result only this time a little further into run-in.
There was another symptom I noticed. When the gearbox was assembled but out the car, when I twirled the shaft that the slipper and spur attach to it wasn't completely smooth. It felt like every 1-2 turns there was some imperfection that the gears had to roll over. I can't see this affecting the diff, although I don't know enough to tell.
I'm a bit at my wits end. I don't know what I'm doing wrong. My sense of it is I'm over-tightening the thrust bolt and the pressure is simply ripping the head off.
I'm now out of thrust bolts so will have to get more.
Are there any pointers anyone could suggest. I really want to get this right.
Maybe I should start with a really loose diff then tighten up? I think I'm starting too tight.
Thanks for the help.
I've had this once, snapping the head of the bolt…
If the rings are grooved very badly, buy a diff rebuild kit and some new 3/32" big balls for the diff.
And rebuild the whole diff as the video or the T4 manual suggests.
Clean all the gears with a toothbrush and some motor spray, look carefully for some imperfections on the teeth of the gears. if this don't solve the problem, maybe it's time to change all the gears. that might solve the imperfection,
04-27-2013, 07:01 AM
#302
This may have already been covered but I missed it.
I had been rebuilding my sons diff after every weekend. Doing everything as recommend and the different were so smooth in the beginning of the day.
This is for a 2wd not 4wd........
A couple weeks ago we were racing and a team driver noticed my son was on his side and hitting the power trying to roll the car back on its wheels. He yelled out to me "that diff is toast", well he was right, the truck would shoot to the right on the gas and to the left on the coast.
Later he explained to me that the diff can't take the extreem pressure of full throttle and one wheel not turning.
He is absolutely correct, I have not had to rebuild a diff since he explained this to me and my son.
So in other words "wait for the marshal to flip you back on your way" your diff will thanks you!
I had been rebuilding my sons diff after every weekend. Doing everything as recommend and the different were so smooth in the beginning of the day.
This is for a 2wd not 4wd........
A couple weeks ago we were racing and a team driver noticed my son was on his side and hitting the power trying to roll the car back on its wheels. He yelled out to me "that diff is toast", well he was right, the truck would shoot to the right on the gas and to the left on the coast.
Later he explained to me that the diff can't take the extreem pressure of full throttle and one wheel not turning.
He is absolutely correct, I have not had to rebuild a diff since he explained this to me and my son.
So in other words "wait for the marshal to flip you back on your way" your diff will thanks you!
06-01-2013, 07:18 AM
#306
06-01-2013, 09:03 PM
#307
06-07-2013, 12:38 PM
#308
Tech Rookie
I got the TLR kit & installed the Ball Diff kit on my xxx-sct
I snapped the screw on the first one from over tightening & I did better with my second 1 & had it last me a few months....& then that 1 snapped to but lasted way longer
I'm gonna be installing my 3rd ball diff now & have gotten better at it....word of advice to all new ball diff user's/installers don't get frustrated, it's gonna take a lot of trial & error to perfect them.
Losi has a YouTube channel & has a nice install Video & how to break it in....it's about 4-5 minutes long & is easy & Helpfull
I snapped the screw on the first one from over tightening & I did better with my second 1 & had it last me a few months....& then that 1 snapped to but lasted way longer
I'm gonna be installing my 3rd ball diff now & have gotten better at it....word of advice to all new ball diff user's/installers don't get frustrated, it's gonna take a lot of trial & error to perfect them.
Losi has a YouTube channel & has a nice install Video & how to break it in....it's about 4-5 minutes long & is easy & Helpfull
06-11-2013, 11:13 AM
#309
wrong topic, delete this answer please.
06-21-2013, 04:27 AM
#310
Tech Apprentice
Guys, pls. help me to find the right setting for my diff.
From one hand, there is a rule "tighten until you can't move the gear with your hand while holding 2 outdrives", from other hand, AE setting rule is "tighten fully then back 1/8 turn"
My issue is that there are 1.5 turns between the settings, ie if I tighten until I cannot move the gear, I still have to tighten 1.5 turns more to get to the AE setting.
Is this normal? Which setting should I use? I know it's a matter of personal preference, but still...
From one hand, there is a rule "tighten until you can't move the gear with your hand while holding 2 outdrives", from other hand, AE setting rule is "tighten fully then back 1/8 turn"
My issue is that there are 1.5 turns between the settings, ie if I tighten until I cannot move the gear, I still have to tighten 1.5 turns more to get to the AE setting.
Is this normal? Which setting should I use? I know it's a matter of personal preference, but still...
07-28-2013, 11:57 PM
#311
Tech Apprentice
iTrader: (5)
Yep...as has been recommended to me.
My trick for holding them is super slick. I use the back a toothbrush handle and fix some servo tape to hold BOTH washers at the same time. This serves two purposes: one, it's fast...and two, it helps to hold the washers flat.
Try it!
My trick for holding them is super slick. I use the back a toothbrush handle and fix some servo tape to hold BOTH washers at the same time. This serves two purposes: one, it's fast...and two, it helps to hold the washers flat.
Try it!
08-09-2013, 05:46 PM
#312
Tech Rookie
That sounds great! Thanks for sharing those great resources. 
08-09-2013, 07:05 PM
#313
Guys, pls. help me to find the right setting for my diff.
From one hand, there is a rule "tighten until you can't move the gear with your hand while holding 2 outdrives", from other hand, AE setting rule is "tighten fully then back 1/8 turn"
My issue is that there are 1.5 turns between the settings, ie if I tighten until I cannot move the gear, I still have to tighten 1.5 turns more to get to the AE setting.
Is this normal? Which setting should I use? I know it's a matter of personal preference, but still...
From one hand, there is a rule "tighten until you can't move the gear with your hand while holding 2 outdrives", from other hand, AE setting rule is "tighten fully then back 1/8 turn"
My issue is that there are 1.5 turns between the settings, ie if I tighten until I cannot move the gear, I still have to tighten 1.5 turns more to get to the AE setting.
Is this normal? Which setting should I use? I know it's a matter of personal preference, but still...
I have a xxx-sct and because I blew up two prior to this current one I am using we tightened all the way down then backed 1/8 off. Broke it in, then tightened a little more, and then ran it and I check it after every other race for tightness and pull the ball diff out to check the gears after every few race days. I also like my diff a little tighter, could be because I am afraid to blow it out again LOL. Another good tip is you never want to stop at the loosening...you want to have it set during the tightening. In other words if it says to back it out an 1/8, I will back it out just a little more then the 1/8 turn, then tighten it up to the 1/8th where it would stay.
09-05-2013, 10:52 AM
#314
Racing on and off for nearly 30 years I have tried it all.
Setting the diff in your hand, holding the outdrives with two flat screwdrivers while spinning the gear with your fingers is a great "baseline" starting point. Your fingers should hurt a ton trying to slip the gear this way if it's close.
I have tried dozens of greases, different techniques for sanding and prepping the rings and thrust washers, nothing works better then having the slipper slip before the diff does!
If the slipper has to be really loose to slip first, the diff is too loose. You should be able to force the slipper to slip on the work bench, before the diff. You'll know because the spur gear will turn, but not the top shaft/adjustment nut. If the top shaft turns the diff slips first.
Tips: adjust the diff bolt close, turn the diff outdrives and gear to work them in each half turn or so once your close. Keep working them while tightening a little at a time. This is seating the rings, balls, washers and gear and lining everything up at the same time for best results in the final setting.
Too much grease will not make the diff last longer and not enough will shorten it's life span. The ball cavity in the diff gear should be full of grease on both sides during assembly, grease should not be dripping out all over the work bench during tightening. Same for thrust assembly... fully cover the balls, that is enough.
The direction of the diff bolt only matters for access to adjust it later. Direction will not determine if it loosens or not, the condition of the diff nut and thrust assembly determines that.
Think about it, the threads are right handed. Nut on the right would loosen when right wheel spins more, nut on the left it would loosen when left wheel spins more.
Only the condition of the nut and thrust matters here and access to the bolt to your preference.
Hope this helps.
Jim
Setting the diff in your hand, holding the outdrives with two flat screwdrivers while spinning the gear with your fingers is a great "baseline" starting point. Your fingers should hurt a ton trying to slip the gear this way if it's close.
I have tried dozens of greases, different techniques for sanding and prepping the rings and thrust washers, nothing works better then having the slipper slip before the diff does!
If the slipper has to be really loose to slip first, the diff is too loose. You should be able to force the slipper to slip on the work bench, before the diff. You'll know because the spur gear will turn, but not the top shaft/adjustment nut. If the top shaft turns the diff slips first.
Tips: adjust the diff bolt close, turn the diff outdrives and gear to work them in each half turn or so once your close. Keep working them while tightening a little at a time. This is seating the rings, balls, washers and gear and lining everything up at the same time for best results in the final setting.
Too much grease will not make the diff last longer and not enough will shorten it's life span. The ball cavity in the diff gear should be full of grease on both sides during assembly, grease should not be dripping out all over the work bench during tightening. Same for thrust assembly... fully cover the balls, that is enough.
The direction of the diff bolt only matters for access to adjust it later. Direction will not determine if it loosens or not, the condition of the diff nut and thrust assembly determines that.
Think about it, the threads are right handed. Nut on the right would loosen when right wheel spins more, nut on the left it would loosen when left wheel spins more.
Only the condition of the nut and thrust matters here and access to the bolt to your preference.
Hope this helps.
Jim
09-26-2013, 10:32 AM
#315
Tech Rookie