G&G MP5 Gearbox cracked

[Tormented Penguin]

Noticed my gun was shooting well under what it used to.. on closer inspection the gearbox is cracked. I believe it is a version 2. My question is with G&G can i put in any version 2 gearbox, or does it have to be a specific one? I figure it would be better to buy a new complete gearbox since i bought the gun used and now I can build it to what i want. If anyone has one for sale can you PM me.. did the whole AV thing like a month and a half ago and i'm still waiting for the forums to catch up. Thanks

Edit Just found my hop up is not working properly as well .. sweet complete rebuild time.

[MaciekA]

Originally Posted by Tormented Penguin

Noticed my gun was shooting well under what it used to.. on closer inspection the gearbox is cracked. I believe it is a version 2. My question is with G&G can i put in any version 2 gearbox, or does it have to be a specific one? I figure it would be better to buy a new complete gearbox since i bought the gun used and now I can build it to what i want. If anyone has one for sale can you PM me.. did the whole AV thing like a month and a half ago and i'm still waiting for the forums to catch up. Thanks

Edit Just found my hop up is not working properly as well .. sweet complete rebuild time.

You don't need AV to find gearboxes, check airsoftstore.ca or airsoftparts.ca .

Airsoftstore has a complete Lonex v2 that MAY work very well. Take note of the word "may". You'll need to ensure several things before you race ahead with this.

First, your mp5's nozzle may or may not be slightly different from the one that is supplied with the Lonex gearbox. I'd actually try to hold onto that nozzle in case you end up needing it.

Second, if you think your hopup is not working, you should first look into only replacing the bucking and nub for now since the actual hopup unit is typically indestructible and likely works well in your gun. If you had a hard-enough firing gun that you cracked your gearbox, it's entirely possible you had a hard-enough firing gun to shred your stock bucking. Also, the hopup in a G&G MP5 is different from most hopups you're going to find on sale in airsoft part stores.

Third, unless your MP5 is different, your selector plate will likely be an MP5 selector plate, which is different from a typical V2 selector plate. If this is the case, you will need to transfer the plate from your G&G mechbox to the Lonex mechbox.

Fourth, you will likely need to re-shim the Lonex gearbox from the bevel gear to mesh well with your pinion gear. This isn't easy on MP5s since it's impossible to get a good look at the mesh while the motor is in the grip. All I can suggest here is starting with the fat side of the bevel gear as low to its corresponding shell wall as possible, and then going from there. Your G&G's stock motor height is likely fairly close to where you want it, with only a small amount of easing-off (perhaps 1mm or so) in case the angle of the Lonex teeth is too steep.

Finally, if you are apprehensive about the above steps and think you'd rather not take your chances with precise compatibilities and selector plates and meshes, one other option that will definitely work is to go to G&G's own website in Taiwan, find the exploded diagram of your gun, and send them a request for the replacement part.

You can email them at support@guay2.com , they then send an invoice to your Paypal account, and they send you the part immediately. This is a very good option with non-M4 V2 gearboxes, such as MP5s and PDWs, which sometimes have weird selector plates and other stuff.

Here are exploded diagrams for several G&G MP5s:

http://guay2.com/web/drawings/smg/PM5-A5.pdf
http://guay2.com/web/drawings/smg/PM5-A4.pdf

You'll notice these first two have identical gearboxes and hopup units. The hopup units are not standard v2 hopup units but rather slightly modified MP5 hopup units. You'll have to ask G&G what the part number for the complete PM5-A5/A4 gearbox is, but they'll definitely have it.

If you have a blowback MP5, you might want the complete gearbox from this diagram, which has part number GMP5-BBP-22 :

http://guay2.com/web/drawings/smg/Gm...ck_explode.pdf

Notice again that the hopup unit is the same as the other two, and is different from a "standard" (m4) v2 hopup. The part number of their hopup is GMP5-BBP-06 .

[Stealth]

Originally Posted by MaciekA

You don't need AV to find gearboxes, check airsoftstore.ca or airsoftparts.ca .

Airsoftstore has a complete Lonex v2 that MAY work very well. Take note of the word "may". You'll need to ensure several things before you race ahead with this.

First, your mp5's nozzle may or may not be slightly different from the one that is supplied with the Lonex gearbox. I'd actually try to hold onto that nozzle in case you end up needing it.

Second, if you think your hopup is not working, you should first look into only replacing the bucking and nub for now since the actual hopup unit is typically indestructible and likely works well in your gun. If you had a hard-enough firing gun that you cracked your gearbox, it's entirely possible you had a hard-enough firing gun to shred your stock bucking. Also, the hopup in a G&G MP5 is different from most hopups you're going to find on sale in airsoft part stores.

Third, unless your MP5 is different, your selector plate will likely be an MP5 selector plate, which is different from a typical V2 selector plate. If this is the case, you will need to transfer the plate from your G&G mechbox to the Lonex mechbox.

Fourth, you will likely need to re-shim the Lonex gearbox from the bevel gear to mesh well with your pinion gear. This isn't easy on MP5s since it's impossible to get a good look at the mesh while the motor is in the grip. All I can suggest here is starting with the fat side of the bevel gear as low to its corresponding shell wall as possible, and then going from there. Your G&G's stock motor height is likely fairly close to where you want it, with only a small amount of easing-off (perhaps 1mm or so) in case the angle of the Lonex teeth is too steep.

Finally, if you are apprehensive about the above steps and think you'd rather not take your chances with precise compatibilities and selector plates and meshes, one other option that will definitely work is to go to G&G's own website in Taiwan, find the exploded diagram of your gun, and send them a request for the replacement part.

You can email them at support@guay2.com , they then send an invoice to your Paypal account, and they send you the part immediately. This is a very good option with non-M4 V2 gearboxes, such as MP5s and PDWs, which sometimes have weird selector plates and other stuff.

Here are exploded diagrams for several G&G MP5s:

http://guay2.com/web/drawings/smg/PM5-A5.pdf
http://guay2.com/web/drawings/smg/PM5-A4.pdf

You'll notice these first two have identical gearboxes and hopup units. The hopup units are not standard v2 hopup units but rather slightly modified MP5 hopup units. You'll have to ask G&G what the part number for the complete PM5-A5/A4 gearbox is, but they'll definitely have it.

If you have a blowback MP5, you might want the complete gearbox from this diagram, which has part number GMP5-BBP-22 :

http://guay2.com/web/drawings/smg/Gm...ck_explode.pdf

Notice again that the hopup unit is the same as the other two, and is different from a "standard" (m4) v2 hopup. The part number of their hopup is GMP5-BBP-06 .

The thoroughness of your posts continues to astound me.