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The Modify-Tech V3 Torus Gearbox

Modify-Tech V3 Torus Gearbox Review

Back in the day, I did a review on the LCT Airsoft AMD-65 and since then it has become one of my favorite airsoft replicas. Its build quality, finishing on the steel and dimensions matching the real life version but my replica never received the much deserved attention on the inside: a gearbox that matches the replica in quality.

The early LCT Airsoft guns had only one "weak" point: the gearbox (they were fine for the job of pulling an SP90). Since then, a lot of things changed and the new LCT Airsoft guns come with proper gearboxes right out of the box. But back then, a new LCT gearbox was not available. I've replaced my original gearbox with an upgraded JG V3 gearbox after my review of the AMD-65 that had gearbox that was good but I always had some issue with it no matter how carefully I put it together. One day I saw the news from Modify in my inbox that their complete V3 gearbox is finally ready. I have seen a lot of good V2 gearboxes and I own a few of those but my favorite gearbox so far was the Torus from Modify. So I decided to try their V3 as well. I just couldn't wait until the retailers start to sell these so I asked Modify to sell me one and they kindly agreed.

I spent nearly a day looking at it from left and right after I got it out of the box. This gearbox is a work of art, too bad I do not have a transparent AK receiver. The gearbox feels more solid than its V2 counterpart. All its little details are perfect and I can tell that Modify put a lot of effort into this project.

Sometimes you buy an expensive gearbox and it doesn't look apart from a $30 plain gearbox. Well, this is definitely not the case with Modify's Torus gearbox. The coating is the same as what we can see on all Torus gearboxes. The combination of the gearbox coating and the checkered cylinder gives this V3 a professional look. At the front end of the cylinder is a small piece of the blue anodized cylinder head that is visible and this also adds to its professional look.

I really like the interlocking zigzag design on the top. It helps the stopper rail do its job even better. V3 gearboxes aren't held together by screws on their top side like the V2 for example, so any improvement in this area is better than nothing at all, although I have yet to see a V3 split open on the top due to stopper rail failure.

Cabling and soldering on the firing switch connectors are perfect, the unit comes with a Deans connector which is a plus in my book. The connector is good, tried it with three different brands of female connectors and the result was a snug fit with each. Most of my AEGs and batteries are converted to use this type of connector and its advantages are proven a number of times on many platforms and since I opted for a speed gearbox, a Deans connector is a must. There is no fuse on the wire and I do not think we should read too much into that fact. If you adjust your motor height correctly and all your components from motor to battery are fine then you don't really need a fuse. Of course things can go bad but I can't remember a single time when I ruined a battery or motor only because my wiring was not fused.

On V3 gearboxes, the motor is contained in a motor cage which Modify provided for me with this unit but by default the Torus comes without a motor cage. If you're running a JG or an old LCT and planning to upgrade to this Torus gearbox then I advise you to buy Modify's motor cage as well. I only tried JG and LCT but none of them worked because the Modify gearbox is a little wider in that area and modifying the motor cage could ruin the angle and height of the pinion gear.

This optional redesigned Modify motor cage is very nicely casted and provides a snug fit for most motors. Some of you might know how it feels when you're shooting semi-auto and the motor is dancing around in its cage under the pistol grip when it speeds up and stops but Inside this cage the motor moves very minimal around its axle. I only had trouble fitting SHS motors due to their higher brush-springs. I tried Golden Eagle, Chao Li, Guarder and Tornado (GFC) motors and all of them worked just fine but the best fit was the Guarder motor. Modify recommends using a standard motor with a speed gear set, but I was planning to run this gearbox at 7.4V so I needed a bit snappier motor. After the initial tests I decided to go with the Guarder HT motor since the SHS was a bit too snappy and it did not fit the motor cage perfectly. Running the Guarder HT motor allows me to freely choose between 7.4V LiPo or 9.6 Nimh batteries.

Taking the gearbox apart you will need a number 10 Torx key which was supplied with old V2 Torus units but not with this one. Having Torx screws on the gearbox is the next best thing after sliced bread but make sure you got one laying around when dealing with a Modify gearbox. Spring tension can be released on Modify gearboxes with a small flat head screwdriver through the anti-reversal latch since its axle is slotted.

What I like about the gearbox the most is when you take it apart you don't have to worry about anything other than the main spring. The anti-reversal latch or the gears won't jump out of their place and you won't lose any shims because all three gears are sitting on a frame. Most of the inspection and maintenance can be done through the holes on the side of the gearbox but when you do take it apart this setup is much easier to work with. The main difference between V2 and V3 Torus on the outside (except the obvious fact that one of them is V2 and the other is V3) is that the V2 version has a small port where you can check the angle of engagement and current health of your piston's first gear. But in this area the V3 has a threaded hole for the AK fire selector lever. The Modify writing on the top of the gearbox is partially covered by the cabling, I would've placed it somewhere when it's more visible when you lift the top cover of an AK, or even engrave the Modify logo on the cylinder because that part is visible even from the outside when you flip the selector lever to anything other than SAFE setting

On the inside you find the same quality you'd expect at this price range. I have intentionally opted for the speed gearbox so I won't expect full steel teeth piston or aluminum piston head but it looks like any other part in this gearbox would be happy to take the beating from a serious spring like a 130 or even a 140 (not that if I want to put those in a high speed setup). The first thing I noticed that the gearbox is very clean and the last time I saw this tidy gearbox was when I opened my Systema Revolution gearbox. Instead of grease Modify used oil on the gears and even on the cylinder head. Most people put the top side of the gearbox aside once they've opened it, but inspecting that top half reveals another nice touch from Modify: the groove of the tappet plate was polished ensuring effortless tappet plate movement and the result of that is smooth feeding.


The SP100 is held in place by a steel rotary-shaft spring guide with bearings and you'd think this is an overkill for a regular spring but the less friction the spring needs to handle, the faster it compresses and it draws less power as well. The spring is an irregular one, the same length as a Guarder SP120 but softer. The piston is a polymer one with the last 7 steel rack and the second tooth is missing. The guide rails on the side of the piston are slotted and each has a grease-groove as well, again what you always see when dealing with Modify parts.

The piston head is also made out of polymer with 8 medium breathing holes and a bearing inside the piston. As you can see on the image I did not take the cylinder and its head apart because the fit was extremely tight (later on this proved to be a wise move since the FPS is awesome due to this spring). I tried to set up an angle where you can see that the aluminum piston head has a rubber dampening. I always do a compression test when I take a gearbox apart, nothing complicated I just hold the cylinder with head and nozzle in my hand and I try to push in the piston while covering the nozzle with my finger. If there is no air coming out of the system then everything is OK. The air seal is perfect in this gearbox, not even the air-seal nozzle leaks under compression. The Modify-red tappet plate is nearly standard V3 tappet plate with the exception of the grease slots on its side. The V2 Torus is using a special tappet plate because of the extra reinforcement at the front of the gearbox. But here it looks like the gearbox would take any standard V3 tappets if there is no Modify tappet available. The heart of the gearbox is the gear frame with the gears. It's always a pleasure to take the frame out of its place and spin the gears close to your ear so you can listen a perfectly shimmed gear set without additional noise like the clicking of the cut-off lever. 

It is fairly large decision to purchase a complete gearbox at this price because the question is there: will it fit my receiver? I was worried for a reason because my LCT is a very early production model but I figured what could go wrong since both companies are keen to follow Tokyo Marui standards. In an AK type receiver, the fire mode selection is done through a series of levers interconnected with gears. This gearbox doesn't come with any since you can put the gearbox into a G36 or SIG-552 as well, not only into an AK and those both have different fire mode selection methods. I have no idea where I put the original LCT fire selector gears or where the ones I used with the JG gearbox came from but they did not work with the Modify gearbox, only after slight adjustment they did work. The problem was that the small triangle looking lever (which blocks the trigger when the gun is set to SAFE) could not follow the curve cut into the gearbox but after modifying this part, the next lever had to be modified where the two levers connect as well. Both parts are made out of pot-metal so a simple file can do the job. I am sure that engineers at Modify used a Marui AK to test this gearbox but since the only V3 replica I have is this LCT AMD-65, I cannot say anything else on the subject than if you are planning to use this gearbox in a receiver from a company having trouble following Marui standards then be prepared to make some modifications. After I solved this problem everything went fine and the gearbox dropped into its place with the fire selector connected, pistol grip attached, ready to test-fire.

Surprisingly, the chrono readings were excellent, even with the stock LCT plastic chamber and barrel my gearbox puts BBs out at 350 FPS with very little or sometimes no deviance (measured with UFC chrono and Gunfire Rocket Pro 0.20g BBs). I could further improve this with a CNC chamber and some Teflon tape but if something's not broken I won't fix it. Modify states their spring is a 100+ spring and I got matching FPS results. A recent addition to my workshop is a 40A DC power supply which allows me to test every gearbox at constant Voltage and read their power draw at the same time. So here are the numbers you were all waiting for: [email protected]: 17; @8.4V: 20; @9.6V: 25; @10.8V: 28; and @12V: 33.  Note that a fully charged 10.8V Nimh battery is 13V and the ROF even @12V is already over the 28 BB/sec what Modify says is safe with this gearbox . If you are running higher voltage batteries then indeed you need a standard motor with the speed setup Torus. Power draw was never more than 14A as far as the power supply can read it.

After the tests I tried to put the receiver cover back into its place and then I ran into my only true problem during the installation. There was no room between the end of the gearbox and the inside of the receiver where the top cover would normally sit on an AK type replica. The place of the gearbox inside an AK type replica is determined by the hole of the fire selector lever on the left side of the receiver, that has to line up with the gearbox no matter what, and it did line up for me but still could not fit the top cover. I've measured the JG gearbox and indeed the Modify is slightly longer. I had no other way than get my Dremel and get rid of some gearbox material. This part of the receiver is not thick enough to remove any material so the gearbox had to be modified. With my Dremel I took off just enough material to fit the top cover. Luckily, the back of the gearbox is thick enough and the material is tough so sanding off a bit won't hurt the strength of the gearbox itself. At this moment I am not sure whose fault is this. On one hand the Modify gearbox is slightly longer than the LCT or JG gearbox but on the other hand Modify states that the gearbox is Marui compatible and my LCT is a very early production model. I do not own a TM AK in order to draw any conclusion. People reported problems fitting V2 Torus into certain G&P receivers and I had to do some sanding as well when I tried to put a Torus into my G&P Sentry. So naturally I raised this issue with Modify and they promised to look into this issue and if my findings are right then they will probably sand off the back of the gearbox before the coating process so no one will have to face this problem in the future. What truly matters is: at the front end of the gearbox is at the place where it needs to be lining up with the Hop-Up chamber perfectly.

Cross-brand airsoft builds often create headaches and to this fact I am already used to. The V3 Torus is in the Lonex/ASG Ultimate range as far as pricing but you get a little more for your money if you choose the Torus and to be honest I never really thought of buying a high end complete V3 until the Torus came out. My DMR AR15 was built using a V2 Torus gearbox with Modify internals and it did not let me down so far, it looks like this V3 Torus will serve me just as well. The fact that the AMD puts out BBs without a problem compensates me for the modifications I had to make.

I had a few more things in my drawer for the AMD and I figured I finish what I started long time ago. I installed a Magwell base from Kabuto which prevents me deep-setting a magazine. This is a pop in piece that only requires some prying tool to force it into its place. The gearbox dimensions are perfect on the front end and this little addition won't affect fps or feeding in any way.

Now that I upgraded my AMD on the inside, I thought I'd look for that old Dynamic Star handguard and gas tube rail, dust them off and install them. Some people like their AKs free of any tactical nonsense, but I say the same about the AK side rail and other impractical but original Russian solutions. Here you can see how my finished AMD awaits the next CQB game. The grip and the rail cover panels come from a company called GIS Tactical. They have many innovative designs for the AK platform but they also make railed handguards for the VZ58 for example. What I like about their rail cover is the complete coverage but low profile and the design/texture fits the AK type weapons extremely well. Hopefully I will be able to get my hands on their railed handguard as well along with the new forward grip so I can show you guys their whole system.