Can you diagnose this problem?

[arch2b]

i bought and received my half eight jdsf and right out of the box i moved my cell pack to my lav and tightened the slipper to the same point it is on my buggy which runs great. i plugged everything in and turn it all on and wham, i get this horrible grinding noise and it goes just about nowhere. absolutely no torque or power behind it. i tried loosening the slipper back to stock and it's worse.

here is a short video
http://mini-zracer.com/mini-zgallery/showphoto.php?photo=5342&cat=895&page=1

[morati]

Your motor is turning, but with some resistance behind it. From here I would say your problem lies with your center diff. It looks as if you are missing teeth on your slipper also.
Possible solution....Remove center diff and slipper assembly and inspect all gears for missing teeth or teeth which have been ground down. Replace as necessary.......Re-Assemble.

[BiGRoB21]

gear mesh is to tight and slipper is slipping. thats what it seems like to me.

[oxfordmist]

If you push it will it roll freely? If not drivetrain. If it does roll ok,(lightpush on a hard surface and it will run away.) Centre diff / slipper. Take it back for a replacement.

[arch2b]

there are no worn or missing teeth on the center diff. it will roll freely.

upon closer inspection the slipper large gear was missing a tooth. can or should i replace just this one with an aluminum gear?

[ChrisOFNA]

I wouldn't suggest that, Id get the 3Racing Delrin gears, only thing is its a locker.

[puppyonfire]

Arch2b,
Try rebuilding the differentials and tightening the screws for the cups. I had the same problem and it went away went i tightened the screw.

Cheers

[Inferno454]

Id start off by resetting your gear mesh.

[arch2b]

i fixed the pinion gear mesh, double checked all the connections and i still get zero power/torque. it takes about 5 feet to get to a slow crawl at near full throttle.

can you explain a bit in more detail on tightening the screws at the cups?

[FHM101]

Have you checked your throttle trim on the transmitter? Does it have the same problem in both forward and reverse? Have you spun it up while holding it off the ground in both forward and reverse? Have you tried running it with the wheels off to see if all four corners are turning at the same speed? Have you removed the motor and run it up to see if it's spinning up like it should? Have you checked to see if it rolls freely with the motor removed?

If it has the open buggy style diffs it might be very bound up due to flash on the gears. The diffs in my buggy were that way and I had to break in the driveline a bit before it smoothed out.

[arch2b]

the throttle trim is correct.

yes, although it does not seem quite as bad in reverse.

yes, the wheels spin freely while off the ground. they so not exhibit nearly as bad slipping while the wheels are off the ground. the front wheels tend to be a bit more responsive with the wheels off the ground.

yes, the motor was removed and runs perfectly.

yes, it rolls with the motor in and more freely with the motor removed naturally.

yes, the jdsf has the same chassis as the buggy counter to initial reports it was essentially an st chassis.

[BiGRoB21]

sounds to me like the slipper is slipping too much with your last post. tighten up the slipper all the way and see if that works

[arch2b]

the slipper is already as tight as it's going to get. i pulled the center gearbox from my buggy which was running great.

[habitforming]

so if you hold the car in place and apply the throttle, does the engine spin up freely, sort of freely, or does it barely spin? Don't go full throttle for this test, you'd likely break something.

If the motor is spinning freely, start looking at the various parts of your drivetrain and tell us what is turning and what isn't (specifically, center diff outer gear, center diff outdrives, front/rear driveshaft). If you see where the rotation stops, then you know where the problem is.

[FHM101]

Sounds like a case of MICDS to me.

[habitforming]

Sounds like a case of MICDS to me.

Yeah, does it look a little something like this?:
http://home.insightbb.com/~habitforming11/img/centerdiffkaboom.jpg