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differential not working (noob needs help)

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Old 07-18-2014, 12:33 PM
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MX26
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Default differential not working (noob needs help)

this is the 2nd time the rear differential on my reely 1:10 truck failed, the 1st time was not long after i got it and i had a free repair, but i want to know how to fix this myself and what the problem is.
at 1st the rear tires start to spin a it slower, then they just keep spinnign slower and slower over time, untill they barely spin at all and the front tires do all the work.
i decided to take it apart and open up the differential, everything looked ok, it was spinning no problem. i closed it again, and it worked perfectly, for a moment anyway... the same thing as before happened, but much faster. it's like the rotation doesn't transfer from the propeller shaft (hope google translated it corectly) to the drive shafts ( once again, i really hope google translated it corectly).
anyone know what exactly is the problem? and if yes, how to fix it?sorry for the bad explenation, don't know most the terms and the ones i do i don't know in english
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Old 07-19-2014, 04:02 AM
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phmaximus
 
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What type of diff is it?? Ball or gear?

with out knowing that the first thing to check is, are the axles attached to the diff? They haven't come loose or dropped a grub screw?
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Old 07-24-2014, 08:23 PM
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sounds like a 4wd truck....so my guess is a loose grub screw between the center diff and the rear diff....if it has dogbones then the input drive cup on the rear diff likely has a grub screw (or set screw) that has come loose. this will allow the input cup to spin freely on the diff's pinion gear shaft.

Or it could be a set screw on one of the output cups from the rear diff. Since the diff is open, all the power will go to the cup but not get to that wheel.

Or one of the wheels could have a broken/missing drive pin behind the wheel hex....or the wheel hex and/or the wheel's hex could be stripped.

got pics?
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Old 07-24-2014, 11:45 PM
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MX26
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figured it out, didn't see it at 1st, but the differental bevel gears are all jus busted. did some research, and it turned out that it's a common problem with reely diffs, gonna sell it and get a new one, thanks anyway.
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Old 07-31-2014, 09:42 AM
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EXT2Rob
 
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If your diffs are getting munched that quickly, sounds like something is wrong. Not knowing your particular car, I am talking in general....but, here are a couple things to think about.

First, make sure the diff case screws are not coming loose. If they are, the diff gears loose mesh and slip, and will quickly get munched. Use some Blue (temporary) Loktite thread lock on the diff screws. You may have to clean the screw holes of any oil. And let the thread lock dry before you re-install it.

Secondly, lube. Gear diffs need lube. Either silicon diff fluid, or gear grease. I use TrakPower Waterproof Gear Grease in my 2wd Evader. Use plenty, but don't pack it in, or the diff will act like it's locked.
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Old 07-31-2014, 12:24 PM
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the diff case screws were good, greased well, on my last diff i noticed the bevel gears were a bit too loose, tinkered with it a bit and made it better, they lasted a whole 40 minutes longer.
the bevel gears are just out of a very bad material, i tried to break a spare one i had with my hands, even toothpicks are harder to break...
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