New gearbox for m4

[Dan88]

My step dad's gearbox has given up on his G&G raider. He's got a tight bore barrel and shs motor in it, he loves the gun and doesn't want to change it.

I'm just wondering what upgrade gearbox you guys recommend to put in? Can you get them with mosfets fitted or am I just being stupid?

Cheers
Dan

[Caldymoose]

Re: New gearbox for m4

What exactly has given up in the gearbox? Its highly unlikely you'll need to replace the entire gearbox, not to mention costly if you choose to do that. There aren't very many pre made gearboxes on the market, the main ones that spring to mind are the ASG Ultimate/Lonex ones, but they retail at £120 ish. The only gearboxes I know of that have the mosfets built into the actual gearbox themselves are the new Krytac ones, but these have only just come out in the US, not seen them anywhere near Euro markets yet. Mosfets that replace the existing wiring loom are abundant out there, so if the gun is getting rewired, you may as well just buy a mosfet that comes with the wiring loom and install it that way.

Anyway, back to the point, try and find out whats failed on the current one.

Does the motor still turn over but theres a grinding sound? Could be a pistons stripped
Does the motor not work at all? Could be an electrical short/fault, gearbox could be locked up, or the motor could have failed


Theres a long list of things to go wrong with a gearbox, so try and find out more about whats broken, then we can help you solve the problem. Either way, I'd say its doubtful you'd have to replace an entire gearbox. Unless the shell itself has suffered a failure, in which case the shell will need replacing. The more info you can give us the better!

[Dan88]

Re: New gearbox for m4

Cheers for the help mate.

The gun fires but it's just like a whining/spinning noise. As if the gears are shredded?

He wants to upgrade the box so saw this as an opportunity really

[Caldymoose]

Re: New gearbox for m4

So the motor and (probably) gears are turning, but the piston isn't cycling? Sounds like the piston has shredded its teeth. Happens sometimes, easy enough to fix. Remove the gearbox from the receiver, open it, carefully, then if it is the piston thats gone, clean out any gunk/piston shreds and install a new one. If you are wanting to upgrade some parts, you may as well do it all at the same time when the gearbox is open.

Only way to know 100% whats wrong is to open it up and see, but from what you've said it sounds like the pistons done.

[Dan88]

Re: New gearbox for m4

Cheers mate. I'll have a look at it tomorrow.

[Jouichirou]

Re: New gearbox for m4

Tried the motor height adjustment screw ? No one mentioned it and you may have already fiddled with it, leave no stone unturned

[whiteman]

Re: New gearbox for m4

if gb works there is no any reasonable reason to replace it, unless is cracked.

if your dad wants to upgrade,i suggest to use a good lube ( proper Teflon grease you can get i bike store or ceramic grease ). and make sure that compression is very well ( tpfte tape to seal up any air leakage ). it is the simplest upgrade

secondary- reshimming, and rewiring +mosfet

finally- motor ( high torque ) and gears ( low ratio: 14:1 ), piston ( make sure AOE is correct- you will find tutorials on YT ) , piston head, o-ring, spring guide ( in past it was must, now it isnt necessary )

The best and strongest gb i have and i have seen was made by KWA.

[smudge1990]

Re: New gearbox for m4

Tried the motor height adjustment screw ? No one mentioned it and you may have already fiddled with it, leave no stone unturned

I've had this a few times, and would recommend trying this first.
Here is a video to assist you:

https://www.youtube.com/watch?v=D3a1Xqbevog

[smudge1990]

Re: New gearbox for m4

Any joy repairing this, Dan?