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View Full Version : Diagnosing a blown diff



SteveR1960
01-13-2007, 12:25 PM
Well - I have a classic blown diff issue. Car has four wheel drive when not under load, but under load it doesn't move easily. Motor, slippers and the like are fine. Since this thing has three diffs, what is the easiest way to dianose which diff is bad so I selectively tear the baby apart and only order the correct diff?

wartown
01-13-2007, 01:25 PM
Check the center first. if it is not the center then order a diff for the back or front. They are the same so you can not go wrong.

gazzer55
01-14-2007, 12:48 AM
I have a similar problem. I just installed some 09 diffs and after hooking up the motor and running for a while it sounds like something is stripping and the car doesn't move. When I pick the car up the back wheels barely rotate. I'm going to dissasemble the center diff, I hope thats the problem.

Stickyfingers
01-14-2007, 07:41 AM
what is the easiest way to dianose which diff is bad so I selectively tear the baby apart and only order the correct diff?

I would order all 3. They will all blow anyway.....

gazzer55
01-15-2007, 02:27 AM
My drivetrain seems to be working fine when rolling the car without the motor but when the motor is connected and used there is a huge slipping noise. Could it be my center diff is stripped? How can I go about locking my center diff to see if that helps it?

dickdastardly
01-18-2007, 10:47 AM
man these diffs suck!!!!!!

i got the 3racing blue gears and its stripped on the 1st run, i think it is because of chassis flex as it happened when i was going round a long corner under power i geuss the pinion came out a bit and the power took the top of the gears off around a quarter of the gear. dose this sound possible????
sorry iam a Ep newbie and only driven a serpent 710 so not used to all these probs. i think it has done some damage elsewhere to as i change the slipper for a new 1 as i got 3 in the bag and i still get a clicking when i pull away
any ideas what else would be damaged???

also what is the best replacment for the f/r diffs and center??? i hear the 3r and atomic are crap?????

i was think to go brushless but theres no point if the diffs aint sorted( i only have a rocket 400 and IB 14000 pack ,stock electrics.

so if thats gonna blow gears, wats the point in getting more power...

can some 1 please explain or point me to somewhere that tells me how the gear ratios work?

form what i can make out the low the pinion the faster you car but with less top end, the higher the more top end , but how dose this work in conjuntion with the slipper what if i put low pinoin and high slipper???

and why do you gear down if your motors to hot? more accelaration more revs hotter motor no???

thanks for the time i got a lot to learn about these cars.....

oh i got the ST so i got the sealed diffs f/r

beast95451
01-19-2007, 01:36 AM
Well I just ran in to a problem after replacing both the front & rear diffs with 3racing ball diffs. After putting everything back together, I too notice that I have 4wd with the buggy in the air (no load). When I set it down to run it, it sounded like the slipper was slipping bad. So I put it on the bench, hold the buggy down & hit the throttle. The slipper is not slipping, BUT both front & rear center dogbones are moving, but not the wheels. Almost as if the pinion is not even hitting the ring gear. I did notice some play of the white ring gear on the ball diff. Am I missing something? How tight does the ball diff need to be? WTF?

beast95451
01-19-2007, 05:15 AM
Nevermind...I had the ball diffs too loose & the ring gear was just spinning on the diff.

pllbz
01-20-2007, 02:49 AM
a good way to check to see if your diffs are stripped is to put the car on its side with 2 tires pointing up and 2 on the ground.......then hold the center dogbone with your finger and spin the tire pointing up. if the tire spins then the gear is stripped....dont force it though because you're putting load on your gears when you spin the tire and can potentially damage the diff...so if it doesn't want to spin....don't force it!if it doesn't spin that means you still have teeth in your diff so your diff is good! do this to the front and rear to check for stripping.