Drivetrain problems

[Norwegian_Savage]

Hi guys, and thanks for the approval! I got a Savage XS Flux just before christmas, and it's a blast to drive! However, I ran into a problem the last time I drove it. When I give it throttle, the engine just spins and I can hear a grinding noise. The truck won't move, but if I pick it up the wheels spin. I have looked inside and all the gears seems to be fine. I have disconnected the drive shaft, and I can easily stop the axle from the engine from spinning with my finger. The only thing I can think of would be that something is wrong with the slip clutch. Any other ideas? Any tips on how to fix this are very welcome!

 

[Jam Racing 1]

well one thing you might do is try turning the spur with the wheels on the ground and see if the slipper is the problem, if it slips easily then try tightening it down all the way and back off 1/8 a turn and see.... as for the "grinding" maybe have a look at the diffs and see if anything is broken.....

 

[h00vy]

I know this is an old thread, but I have a very similar problem. The truck will intermittently run good, but occasionally grind something wonderful. It often happens when I'm traveling forward, then hit the brakes hard, and then apply heavy throttle. It'll grind pretty bad, so I let off the throttle, then immediately get back on it. Sometimes it grind again, but most times it hooks up. It sounds like the spur gear grinding, but the gear looks fine. Could gears be slipping in the gearbox? What does it sound like when the slipper clutch slips?

 

[olds97_lss]

Usually, grinding gears don't last that long once a tooth or two is broken.

Could be your diffs or could be the drive cup is notched really bad causing the dogbone ears to hang up and pop. Could also be your brake discs if you have steel ones. When slop builds up on those, they chatter really bad and bind on the hex.

 

[Caretaker109]

Could also be your brake discs if you have steel ones.

I don't think there are any Brake discs on a Savage Flux or XS..

The diff gears are most likely the problem.

 

[h00vy]

Do the gears in the gearbox ever strip out? The spur and pinion gear look fine, the gearbox gears are hidden (sealed?) Is there any good way to check the diff gears?
I just bought this thing, and supposedly it was running good when he sold it. (a hobby shop sold it on ebay to me) I just finished running it over some hardened snow piles and it worked fine for a while, then suddenly it started locking up again. I tightened the slipper, but didn't seem to make any difference.

 

[Jam Racing 1]

Then it is time to inspect the differential gears, an easy way to quick check is to hold one wheel and turn the opposite wheel, do this for both front and back, look for notchiness or clicking... if you hear any then it is time to remove the diff and see what is broken.....

 

[h00vy]

Then it is time to inspect the differential gears, an easy way to quick check is to hold one wheel and turn the opposite wheel, do this for both front and back, look for notchiness or clicking... if you hear any then it is time to remove the diff and see what is broken.....

When I do as you say, the only clicking noise is the pinion/spur gear. As far as notchiness, it's a little hard to say, cause of the motor clicking. But I would have to say nothing out of the ordinary.
I talked to the hobby shop that I purchased it from, and after listening to the description of the problem, he suggested I open up and inspect the center gearbox. I guess I'll crack that open tonight (hopefully) and see what I can find.

 

[olds97_lss]

I don't think there are any Brake discs on a Savage Flux or XS..

LOL! I didn't notice this was the flux forum when I answered.

Could still be the dogbones notching on you though.

 

[Jam Racing 1]

When I do as you say, the only clicking noise is the pinion/spur gear. As far as notchiness, it's a little hard to say, cause of the motor clicking. But I would have to say nothing out of the ordinary.
I talked to the hobby shop that I purchased it from, and after listening to the description of the problem, he suggested I open up and inspect the center gearbox. I guess I'll crack that open tonight (hopefully) and see what I can find.

well you can always either take off the pinion gear on the motor or just loosen up the motor and pull it away from the drive spur and then check like I outlined above, I have to think if it was in the transmission it would make the sound as it is always going to spin with the spur and that would make the noise constant when you trying to run the truck. either way you need to find and fix the problem before it eats up more parts and gears....