most likely the shim job.

Not for all ICS guns since 2004. Previously they where, now all standard.

Might be wrong but it sounds like either the motor/gearbox gears are mismatched or damaged or not ajusted properly...

To start with redo the ajustment procedure on the motor heigh ajustement screw (spacer?)...
Ps (there is a nice tread on the subject of motor ajustement on ACS)

Because what you are descriving is misengagement of motor gear on gearbox...
a) It pulls the piston half way has tension builds up gears brake contact start skipping teeth...
b) Then screaching sound (Gears grinding themself)

Good luck

Pete

I just remembered.

If you have a cansoft version, the gears they are using are two pieces, the axle and one part of the gear is steel, then the other part is casted over it.

I got an issue where the bevel gear shaft got lose from the beveled section. That caused the same kind of symptoms, and a screeching noize.

If you think you can do it, remove the lower mechbox from your gun, open it and take out just the bevel gear.

Hold the gear with a large pair or plier (with large teeth, so you don't need to apply too much pressure) on the small gear section, and try to force the large section to spin on it. If it moves, even so much, it means that this is the problem.

Solution: Change gear set. I recommend you a Modify set, but not the ones with the bracket. Just a regular gear set.

Aright, I found out I blew a fuse, i think thats a problem.

That is a symptom.

The problem is what caused the fuse to blow.

well if i shimmed the box too much that would cause some bind issue right? so that means the motor wouldnt work properly, Energy overload=Fuse blow, I dont remember what makes fuses blow.lol im probably wrong.

Easy to check. Remove the grip plate (to let the motor pull out of the gears)

Crack-open the receiver.

Spin the gears. It should be fairly easy to spin (since you are against demultiplication, it is harder to spin the bevel from the spur). If you really have to push hard, that might be the problem.

But if you shimmed the gun too tight, it would not have worked from the time you closed the mechbox.

IT was the shim job..the gun is fixed! thanks for the help guys! but hey I learned how a mech box works now lol, I ain't afraid to open it up anymore.

I gotta agree on this one A+