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Quick diff question

Quick diff question

Old 07-13-2008, 05:51 PM
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Default Quick diff question

whas a good way to completely clean the inside of your diffs?

today I finally had the balls to take apart my center one, the oil inside had turned to black sludge and was almost empty. I cleaned it with a hose, but theres still a little inside, how do I the rest of that out? or should I even worry about it?


how do I take the damn bearings off? or the little cup thing that the dog bone goes into? I assume its a 8x16 bearing, and I have a few extra so I thought changing them wouldnt hurt.

and about the front and back diffs. I looked at what it would take to take them off and apart.... seems like a pretty big job? is it or is it just a few screws you gotta take off?

thanks
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Old 07-13-2008, 07:33 PM
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Here's how I clean diffs, I take them completely apart and soak all the parts in Brakclean (non chlorinated) same stuff as Nitroclean, just cheaper from an auto parts store. I'll spray the diff case to get as much oil out as possible, and then let all the parts soak, I'm not sure if it was this forum or another, but there was a big thread about this subject with a lot of different ways to clean a diff.

It is a pain in the Ars to change the oil in diffs, but it should be done on a regular basis, the oil doesn't last forever and you don't want to cook a diff. How often is up for debate, but I usually rebuild the diffs and shocks every half gallon.
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Old 07-13-2008, 07:34 PM
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since you dont race, why bother?
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Old 07-13-2008, 07:39 PM
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Originally Posted by imaxx21
since you dont race, why bother?
Racer or Basher, I would think it's still a good idea to service a car? Preventive maintenance will save you money in the long run
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Old 07-13-2008, 07:43 PM
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Originally Posted by nitrodog
Here's how I clean diffs, I take them completely apart and soak all the parts in Brakclean (non chlorinated) same stuff as Nitroclean, just cheaper from an auto parts store. I'll spray the diff case to get as much oil out as possible, and then let all the parts soak, I'm not sure if it was this forum or another, but there was a big thread about this subject with a lot of different ways to clean a diff.

It is a pain in the Ars to change the oil in diffs, but it should be done on a regular basis, the oil doesn't last forever and you don't want to cook a diff. How often is up for debate, but I usually rebuild the diffs and shocks every half gallon.
I found out how to take mine almost all the way apart. I couldnt access the bearing that was attached to the platic cup. I figured out the one on the pur gear. I was able to get it pretty clean, then I put a little Losi green slime on the dogbone cup like it said in the instruction book.

I dont have that stuff to soak them in, otherwise I would do that.

I cant believe you change yours every half gallon!!! thats crazy.

what is a good oil to put in the centre diff?

Originally Posted by nitrodog
Racer or Basher, I would think it's still a good idea to service a car? Preventive maintenance will save you money in the long run
imaxx is just being a douchebag.

thanks for all the help nitro.
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Old 07-13-2008, 10:50 PM
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Newbie here Also! I do change Diff Oil like every two to three hard running. Center Diffs are the easiest to take out. Front and Rear almost the same. I just take out the two screw underneath the chassis that holds the front Bulk Head or the rear bulk head. Take out 4 more screws in front to take out the fornt bulkhead (Front and rear gearbox are identical). You can access the diffs now to pull it out. Takes me less than 5 minutes to do front and rear. The cleaning part will be harder IMO.
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Old 07-13-2008, 11:02 PM
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Originally Posted by oggietiu
Newbie here Also! I do change Diff Oil like every two to three hard running. Center Diffs are the easiest to take out. Front and Rear almost the same. I just take out the two screw underneath the chassis that holds the front Bulk Head or the rear bulk head. Take out 4 more screws in front to take out the fornt bulkhead (Front and rear gearbox are identical). You can access the diffs now to pull it out. Takes me less than 5 minutes to do front and rear. The cleaning part will be harder IMO.
hmm, I will need to take a closer look at it, if my center was black sticky sludge then im guessin the center and rear are too

I still cant figure out how to get the 2nd 8x16 bearing off
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Old 07-13-2008, 11:27 PM
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Originally Posted by new to rc cars
hmm, I will need to take a closer look at it, if my center was black sticky sludge then im guessin the center and rear are too

I still cant figure out how to get the 2nd 8x16 bearing off
Your talking about the bearings on the out drives..right..On one side their is a pin that holds the diff half in..remove the pin out drive comes out and the bearing comes out..As everyone has said you need to get some nitro clean or brake clean..The black sticky sludge your referring to is grease..replace with silicone diff lube..I am under the assumption that we are talking about an 1/8 scale here..
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Old 07-14-2008, 01:47 AM
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The gears i soak in carb cleaner $1.39 from Wal-mart the cases i wipe out with a rag and Q-tips. After about every 3rd race weekend.
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Old 07-14-2008, 02:20 AM
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Originally Posted by new to rc cars
hmm, I will need to take a closer look at it, if my center was black sticky sludge then im guessin the center and rear are too

I still cant figure out how to get the 2nd 8x16 bearing off
On the side of diff case is a small screw, remove this and slide pin out then cup comes out then bearing. Avoid cleaning the bearing if your going to reuse 'em. Also,avoid cleaning the o-rings, they screw up real easy. Diff oil, start with 5000 and if your frt. tires ballon go up to 7000. Don't let the clowns on here let you down. The world is full of haters.
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Old 07-14-2008, 06:19 AM
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To be specific:

When you open up the diff case, remove the 4 small gears... be careful, some have washers (shims) on them. Then remove the 2 larger gears... behind the larger gears are pins through the outdrives... slip those out. Some cars have a set screw that acts as a plug that you can remove to make that easier, but most have JUST enough clearance in the case to allow them to slide out. Now pull the outdrives out and change the bearings.

Make sure to get everything back the way it was, and be sure the o-rings around the outdrives are both in good condition, and seated properly in the groove for that.

Not all cars are the same, so pay attention to how it comes apart. Some have shims behind the pins, some don't, some have shims on the small gears, some don't. Since I don't know what you're running, and for that matter may not know your specific car, I can't be more specific than that.

Just wipe them down good with a paper towel and reasseble. You can clean them with denatured alcohol if you want, but it isn't really needed... just wipe them off, reassemble, and fill with whatever weight of diff fluid you are going to use. The diff fluid should be filled to just about the top of the pins that hold the 4 smaller gears. Rotate the diff to work the fluid down in, seat them in place, and top off to about the top of the cross pins... make sure the paper gasket between the diff case and spur (or ring) gear is in good condition, replace if needed.
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Old 07-14-2008, 08:14 AM
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Read the links below. It has good information.

http://www.unlimitedengineering.com/...ad.php?t=19075

http://xtremerc.com/pages/howto.php?howto=24&page=3

Last edited by Tree; 07-14-2008 at 06:11 PM.
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Old 07-14-2008, 10:25 AM
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A good starting point for diff oil is...

5,000 front
7,000 center
3,000 rear
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Old 07-14-2008, 11:24 AM
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Originally Posted by new to rc cars
hmm, I will need to take a closer look at it, if my center was black sticky sludge then im guessin the center and rear are too

I still cant figure out how to get the 2nd 8x16 bearing off
What buggy do you have? If it is the Losi 8ight RTR, chances are that it came with "black sludge" from the factory.
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Old 07-14-2008, 01:25 PM
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Originally Posted by nitrodog
A good starting point for diff oil is...

5,000 front
7,000 center
3,000 rear
first of all I want to say thanks to all that responded, especially DOMIT, there is some very helpful posts in here, thanks. I dont know if im going to tackle my front and rear diffs.. not right away at least. I ordered some 3 and 5000 weight oil.

Originally Posted by tfa8rva
What buggy do you have? If it is the Losi 8ight RTR, chances are that it came with "black sludge" from the factory.
Mugen Mbx5, its a black sludge because it probably went like 2 years without the diff oil being changed.

I am still having a little trouble getting to the other bearing, I will look at it closer and spend more time on it later, I took a real quick look, tried to pull the gear out with needle nose pliers, I was careful but the pliers couldnt get a good enough grip.

and when I changed the other bearing.. it didnt even need to be changed, it looked like a pretty nice bearing, I dont wanna throw it out incase its one of those twenty dollar ones.

pics: thing I cant get out (horrible quality), whole car, my bike
Attached Thumbnails Quick diff question-11.jpg   Quick diff question-22.jpg   Quick diff question-bike.jpg  
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