what could be causing this sound?

[black92coupe]

:?well after a bunch of upgrades/repairs my crawler seems to be acting a bit funny

it seems like somethings binding in my drivetrain and causing it to loose speed at a certain point, the motor sounds like its pulsating
its kind of hard to describe so i made a little crappy video with my phone




specs are pretty basic,
gatekeeper gc3, stock motor and tranny, stock lockers, ive built my own driveshafts also.
ive replaced the motor with a stock replacement, and the esc today

if theres any other things you need to know just ask


any help is appreciated, thanks

[shadowrejects]

hmmm... sounds like it's skipping some gears or a gear is warped... check your pinion gear or slipper clutch and see if its bent, missing teeth... or what.. lol but idk sorry man

[dudeka]

i dont now but something is loose in the gearing........... i think:?

[Crawl_Before_Walking]

First thing is to switch your homemade drive shafts for the stock ones you took out, its the most likely cause of the problem and its very easy to get a bad UJ on there thats just not smooth enough for such a small truck.
If you switch them and the problem persists then take a look below at checking the spur/pinion mesh and condition.



Ok, Im going to go over absolute basics because even the most experienced of us miss them sometimes.

Remove your body and the spur/pinion gear cover.

Start off by checking the mesh isnt too tight as a tight mesh will make even the slightest deformation of your spur gear show up worse than a correctly set one. You should be able to move the spur a fraction back and forth without mmoving the pinion when its set right, the teeth should NOT be pushed all the way together at there tightest point as the spur/pinion turns, turning by hand is the only way to make it slow enough to check this. When its right you should be able to feed a piece of paper into the mesh as it turns and it will compress and deform the paper around the teeth but not chew it up and tear.

Once thats done put the truck on its skid on the stand and look straight down from above as the motor turns at low and medium throttle, you should be able to see if there is any warping to the spur across it width, now do the same looking from the front of the truck straight at the spur again, you should now be able to tell if there is any deformation to the outer circumference and teeth of the spur.

Once thats done, if the problem still persists then strip the whole lot down. Tranny, Diffs, Axles, the lot.

[bigbeave1]

i have the same problem i have mip shafts and the angle is not to bad when i turn the truck upside down it goes away i cant figure it out i take the shafts out and spinn the wheeles and the axles are smooth
good thread

[black92coupe]

thanks for all the help guys
it ended up being one of my oversized driveshafts contacting the cover that goes over the spur and pinion gears