First of all, I think this is a very good Lego car whoever whatever says. And if you apply the modifications written below you would get a better one than the instruction says.
But for that you need to assemble precisely first according to the instruction and use fully charged batteries. It won't compete a good RC car of course.

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UPDATE 2022

There are several hints how to improve the performance of your car, some with small modifications others with extensive ones. One morning I figured out a very simple mod and applied it. The effect was incredible, more than expected. We can call it a pure lego modification because the linear actuators work in the same way: just put silicone grease in the wheel hubs. That's all, and you can earn 100 (say one hundred!)% performance increase.

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Faster car

Note if you want your A-model run faster only with the parts included, you will lose torque and the car will be weaker, cannot even run e.g. on deep carpet.
If you check your present construction from the motor to the wheels smaller gears are connected with bigger ones almost all the row. That we are going to change in order.

• 1) Just in front of and one unit under the black, small gear that is directly attached on the axle in the motor there is a L5 grey axle. Remove it (with another an axle removed from the bull bar).
• 2) Now one part felt and a comp got loosen. This comp is attached to the under-carriage assy with two red L2 beams and two blue L3 pins on the sides just next to the grey axle that sticks out half a unit to the front. Remove them.
• 3) Now you can reach the small black and the big yellow gears. Interchange them. (Don't bother with the grey gears.)
• 3b) If you want now you can reassemble everything. If you continue you can get a more faster car

The next gears you have to interchange are just next to the differential-gear: the small, black ones joint with axle and big, yellow ones connected to them. You need to unjoin the wheel hubs and disassemble the lower part of the under-carriage assy.

• 4) Remove the wheels to reach the parts.
• 5) First you need to remove the tie-rods (L8 grey stop-pin axle full of ringed parts on them). Be careful not to break anything, pull them in small steps.
• 6) Now the wheel hubs are fixed to the assy with 2x2 axles: one L3 grey axle down and one L2 red axle up both sides. Remove them and pull the wheel hub out.
• 7) Turn the car upside down and remove the L11 red beam that is under the black split perpendicular connector of the wheel hubs. It will be hard to put it back later ;)
• 8) Remove the two L3 grey beam just next to the previously removed beam. Now 2 comps on the sides felt.
• 9) Now you can reach and interchanged the black and yellow gears on the sides of the differential-gear. Don't bother with the axles, if they come out you can put them the back easily and precisely.
• 10) Because we cannot interchange any other gears you can reassemble everything now. If you want you can disassemble the wheel hub comp to check for dirt and clean.

If we call the process above process-A now you have to continue with the process-B with the same steps on the other under-carriage assy.

If you finished try it on a wide and flat space. Note it can hit something or fall down and break because it is fast now. But it is weak, so flatness is needed.

More stable suspensions, overturn prevention

This is an easy and sustainable modification. It should come onto the market like this. I think there is no point in the original construction. Maybe you need to use tweezers to modify easier.

• 1) Let's start at the front. Just behind the lower part of the suspension there is a 2-part comp made of a grey ring and a L2 blue axle pin. Remove it.
• 2) Now you can unjoin the lower part of the suspension. Unjoin together with the black pin.
• 3) Grab the lower part of the suspension, pull outside, then backward, then try to move it along the wheel-arc of the body. It will come out a bit from the chassis. Pull out and remove the suspension together with the blue pin.

Before we continue check the pins. They are bumped on the cylindrical surface. I think it is another mistake with the suspensions. They cannot turn smoothly, they are stuck. Because I didn't use extra parts (same size in grey or tan) I just took a small file and filed off the bumps. If you do the same way just mark them or whatever to use only for the suspensions.

• 4) Now comes the trick. Hold the removed suspension upside down (yellow part down) and orientate the 2-sized bumpy end inside. Insert the black pin in the upper hole and connect to the chassis.
• 5) insert the blue pin in the lower hole of the suspension and connect to the under-carriage.

Now we earned 1 unit to the side. 2 sides mean 2 units. And this means better leverage of the chassis. Process B-D: do the same process as above with all the 3 suspensions left.

Lower chassis (works only with "More stable suspensions..." modification)

It could be a very good small modification but unfortunately because of the original spring displacement the wheels will interfere with their arcs. But let's do it.

• 1) The same as in "Faster car 1)".
• 2) Remove the L4 red L beams from the side of the under-carriage assy. They are just in front of the yellow gears next to the differential-gear. If you want to stretch a bit the under-carriage assy you can skip 2b) and 2c).
• 2b) Remove the motor by pulling out the four grey L3 stop bush pins on the side of it and put aside.
• 2c) We can remove now the L7 beam just behind the motor.
• 3) Open up one of the two very long longitudinally built red beams on the sides of the motor. They are connected to a perpendicular red beam and the suspension, with a comp that consists of 3 parts: a L2 grey perpendicular connector, a grey L3 2 pin connector hub a blue L2 axle pin
• 4) Remove the 3-part comp and disassemble it. We won't need the L3 connector anymore.
• 5) Use the blue pin and the perpendicular connector to rejoin the suspension to the long beam. Use the connector in the way to connect the suspension 1 unit lower as it was.

A2: do the same with the suspension on the other side. B1-2: do the same on the other under-carriage assy. We earned 1 unite lower chassis now.

If you want to keep this modification you had better instal some limiter to the chassis to prevent the wheels interfering with the arcs. They could be built from L5.5 axles (exactly 4.5 size is needed) installed in the perpendicular beam of the chassis just above where the end of the wheel-bridge comes up (in front of the modified suspension). They will stop the wheel-bridge before the wheels interfere the arcs.

Free run

If you want just to push your car you can do it with one easy modification. If you want to make the front wheel freely steerable there is one more modification.

• 1) The same as in "Faster car 1)".
• 2) Now pull the small black gear not to be connected to te yellow one.

Process-B: do the same on the other under-carriage assy.
Now you got a free run car but without steering. If you need free steering it is recommended only on the front wheels. Anyway the car won't go straight.

• 1) Remove the front stabilisers from the side of the under-carriage and the middle of the chassis.
• 2) Unjoin the ball-joint with the cardan axle inside. But note the cardan axle goes apart randomly so sometimes it is very difficult to reassemble.
• 3) Remove one part from the cardan.
• 4) Reassemble everything.

Stronger scissor lift

This is another mistake in my opinion that shouldn't have been launched in that way. But there will be a little bit of cheating in the modification here. When I assembled the car, some extra(?) parts left; among them 2 pieces of L1.5 dark grey pin. So I used them here.

• 1) Unjoin the black and yellow beams. Be careful after that, because it will affect with a great force on the hinge then.
• 2) Join the very end of the yellow beam to the second hole of the black beam.
• 3) Put the mentioned L1.5 pins in the first hole of the black beam.

Done. Now it is stronger than ever:)

Better interior, more space inside

This modification is the longest, and it had better show some more photos. But I am lazy to write the process step by step. In the photos you can figure them out.
The first time when I assembled the car it was a very uncomfortable feeling watching the seats. First of all, let's think of a real car: the cushions of the seats are somewhere in the same level with the thresholds. Look at this car now. That red thing on the hub should be in the level of the orange thresholds. However hard I tried to lower the cushions I could manage to put them only 1 unit lower because the servo motor and the hub is too high and cannot be moved lower. Once I made a well proportioned lego figure to seat it inside. But yet standing beside, still the car was disproportionately big. And still it could not fit into the car: it was to high and too long. So I made smaller one. Didn't fit either.
At that point I decided to modify the interior. I used the extra(?) parts, so sorry if you don't have the same extra parts. I did not need to disassemble the whole upper chassis I just force opened it a bit.

Roughly I

• 1) removed a L9 grey axle under the dash and put two L2 black pin instead (I moved the axle into the bull bar with 2 pieces of L0.5 rings);
• 2) put pedals, handbrake, hood opener and 4wd gearshift inside (the pedals interfere a bit with the door limiter);
• 3) half modified the backs of the seats (I made them symmetric and made hinge in the lower part);
• 4) totally modified the cushions of the seats (now they bend down when you open the chassis and the lock system is totally removed);
• (5) put a cable holder inside.)

Check more pics here.

Have a good Lego time ;)

Hint: for me the most fun playing indoor is to play on books covered by yoga mattress...

This flagship Technic set has been on everyone's mind since TLC came out with power functions 5 years ago, and probably much longer than that. A real RC car! And boy does this deliver.

Box/Instructions

It's the normal flagship massive box with flip lid. The parts only fill up about half the box which is not as typical with the smaller boxes they have been doing, but that's okay for a set this size. Instructions for just the A set are included in three booklets, with the B set instructions only online. Haven't seen them on the website yet, but I'm sure they're going to be put up soon.

Parts

As I haven't picked up a Technic in a while, there are quite a few new parts that blew me away, but the really great ones are obviously the brand new L motors that are great. More torque than the regular M motors, but they don't take up so much space like the XL. A brand new infrared sensor too. The real coup is the servo motor with the auto correcting to 0 degrees which makes steering a breeze.

The build

The build took me about 4 and a half hours. As has been mentioned, it is not very difficult, but fun to see pieces you attached in the beginning used at the very end to complete the model.

The completed model

This beast is all about the play! The powerful L motors provide the umph it needs to conquer an obstacle course, and the four wheel drive especially useful. Ground clearance is a little bit of an issue at the wheels, but it's not too bad. The suspension is excellent and the build is very sturdy. It can handle some big rolls and drops. The doors are 'locked' in a great way that keeps them from opening easily. It's particularly fun to drive the two front wheels up so it drives solely on it's back two in a supported wheelie. The battery pack is easily reached with the cab flipping up for easy access.

I will say that the color scheme is not my favorite. I don't use stickers so that might have something to do with it, but I would have preferred something like green or blue that was a solid color with some racing stripes or something. I think part of it is the red chassis with the orange and white too. It just seems like a bizarre choice from TLC.

Summary

Overall, this was a great purchase! The new power functions will be useful when I eventually break apart the car, but for now I will be content to keep burning through rechargeable batteries. I'm sure I'll continue to test it's limitations and then make the B model before I make some adjustments of my own, but I am extremely happy with this 2012 Technic flagship and give it a great recommendation!

Let's start with all the positives. This is a really cool toy built out of Lego pieces, and it has amazing playability for a Lego set. You can spend hours driving it around and climbing over obstacles with its functional suspension, high ground clearance, and all-wheel drive. The 42030 Volvo wheel loader also has all-wheel drive, but without proper suspension and ground clearance, it doesn't handle bumps very well. Not so with this dedicated off-road truck. This crawler will run over large Lego tires with ease and can climb fairly steep grades before the motors give out.

The build process is fairly easy for a flagship set and there aren't really any tricky steps that require special attention. It's also somewhat repetitive, as the two axles are nearly identical mirror images of one another. Probably the most interesting thing about the build is that you are asked to attach a lot of temporary structures that are later taken apart. This is done to keep the axles perfectly aligned until they are completed. A servo motor in the center of the chassis controls the steering, while the two axles are each powered by a large motor. The chassis is roughly 2/3 of the build and the body is the remaining 1/3. The finished truck is pretty big, comparable in size to the Volvo wheel loader, although it's much lighter and less dense than that truck. The battery box switch can be tricky to reach if you have large hands, and could have been improved with some kind of extension.

Now we have to talk about the negatives. Although this set offers good performance and playability for a Lego set, it's not very impressive technically and low on realism. Real trucks do not have separately powered axles like this crawler does. I understand that having essentially two engines makes for better performance, but Lego Technic is about teaching people how real machines work, and thus the functions should be more realistic to reflect that. This truck would have been better served by a single XL motor that drove both axles, and was connected to a fake piston engine, which this set also lacks. The Volvo wheel loader does all those things, hence why it is a better Lego Technic set than this one.

But by far the biggest problem with this set was its price. Had it been $140, I would have easily given it 5 stars, but at $200 this set was simply too expensive for its piece count and its level of sophistication for a flagship Technic set. Compare it to what came before and after it and you'll understand what I mean. This set reuses many suspension pieces that were introduced in the Unimog a year earlier, but that set had 50% more pieces than this one, was way more complicated and technically impressive, while costing the same $200. A year after this set was released, Lego gave us the legendary Mobile Crane MK II, with twice as many pieces as this set but only costing $20 more. Piece count isn't everything, but sandwiched between those two behemoths of Lego Technic, this crawler feels like a clear downgrade and a poor value for money. Being a flagship, Lego packaged this set in the same sized box as those two, but don't be fooled by the boxes. The mobile crane box is nearly completely full, while this one is only half full. This set's price per piece ratio is similar to those of the 8043 excavator and 42030 Volvo wheel loader, but the latter justifies its higher price with more motors, more realistic functions, and a license. And the former is arguably considered to be the best Technic set of all-time. The 8043 excavator is a small mechanical marvel in a way that this set just isn't. When looking at all of Lego Technic's flagships from 2009 to 2015, this set is clearly the least interesting and impressive one of the group. It's not bad by any means, but think of it as an average player in a lineup of all-stars.

Then there's the issue that Lego released a limited edition of this set using the same chassis, but with a much prettier body built using special colors, significantly more pieces, and even an extra motor to power more functions. That set was the 41999 crawler, which was sold by Lego for the same $200 price tag as this one. Although that set was limited in quantity and quickly sold out, inflating its value on the secondary market, that money didn't go to Lego, so it's beside the point. 41999 was strictly superior to this set in every single way. This set was simply overpriced at $200, which means I can't give it 5 stars. But don't let that stop you from liking this set or acquiring it. It's really a testament to how amazing Lego Technic was during that period, that this set looks worse by comparison.

The 4x4 Crawler is a very well engineered multi-terrain vehicle. It almost feels like it is designed to showcase some of the possibilities afforded by the new PowerFunctions self-centering servo motor and the torque that the new L motors can crank up. With a sturdy build and ultra-high suspension, this thing is made to withstand rolls that come from having it climb irregular terrain. On the downside, its high suspension puts the vehicle's center of gravity too high and makes it roll to the side a tad too easily.

The build is not too complex and generally fun. Because the front and rear wheels are driven by two separate motors, the mechanics are rather simple. The chassis itself is perfectly symmetrical front-to-back, which means that the build can get repetitive asking you to do everything two or four times in a row. The suspension is basically an improved version of the 8110 Unimog suspension reusing mostly the same parts. However, it is more stable than its predecessor and cleverly manages to avoid the awkward lateral shift produced by the Unimog's short panhard rod system. I believe this is the very first remote-controlled four-wheeler with steering that actually works well.

Design-wise this model is nothing to get too excited about. It is basically a truck-like 4x4 vehicle resembling a number of models that we've seen before. I'd say that it would even look dull, if it were not for the stickers on it. In terms of innovation and design, the Unimog was more dashing (although it was not as meticulously engineered and sturdy as this unit). It seems like Technic has fallen into a pattern of rehashing the same model styles over and over again. Road vehicles, sports vehicles, construction vehicles, tractors, and occasional bike and flyer is all we keep getting these days. A flagship is followed by a medium-scale motor-free version, and later on by a mini-scale version. You get the idea... Gone are the days of clever universal sets (8094, 8082, 8479, for example), space shuttles, and submarines. I kind of wish Technic would try harder to think outside of the box.

In terms of new parts, I like the new servo motor, and the L motors. The new softer 4-band cables are a nice touch too. I only hope that the new polymer formulation used will be at least as long-lasting and oxydation-resistant as the old one. It's nice though to have the cables bend more easily. I am not sure what the 2.0 on the IR receiver stands for, but time will tell.

Pros

• Great new PowerFunction components (servo motor will come in handy)
  
• Sturdy construction (designed to be played with)
  
• The drive train provides lots of torque for climbing steep terrain
• Improves upon the 8110 Unimog suspension
• Excellent detail-oriented engineering (battery pack access, door latching, etc)
  

Cons

• A lot of similarities in the chasis and tire rims to the previous Unimog flagship
  
• Uninspired vehicle model
  
• Lack of clever mechanics or control system
• Rolls over a bit too easily
  

The 4x4 Crawler is a solid model that showcases well the new PF components in the Technic line. It is marvelously sturdy and offers some great playability. Unfortunately, it hardly breaks any new ground design-wise or mechanism-wise.

After Power Functions was released, a lot of people proceeded to build remote-controlled cars. With this set, Lego have caught on and built their own remote-controlled car.

Four-wheel drive, and four-wheel steering, in addition to fixed axles front and rear, long travel suspension, and large wheels mean this is a competent off-roader that can climb over many objects.

When I saw pictures of this set being displayed at a show in early 2012 I was very excited. At the time I was trying to make a simple remote controlled Lego car, and this was an official that that would help solve a lot of my design problems.

An on-going problem with steering remote controlled Lego models is centering the wheels, but it looked like this model had that sorted.

The expected release was around September, so I was very pleased when Argos had it in mid-July, before even the Lego store or website. I bought it immediately.

Box/Instructions

The box is large with a flip-top in keeping with current large Technic sets. It has numerous pictures of the model, and advertises the servo motor within.

Notably, that bags are numbered 1 and 2, all 1 bags are for the chassis, and all 2 bags make the body.

Parts

There are a good variety of standard studless parts, with a few panel pieces.

The Power Functions parts include an infra-red sensor with 2.0 written on the front, I presume that describes a newer revision of the sensor. It seems interchangeable with the older sensor so I don't think it has any new features.

The set introduces two new standard motors. The spin slowly but seem to be very powerful. And a servo motor with self-centring. This is used to steer the wheels. It is a much simpler and more reliable method than we have had to use up till now involving springs and rubber bands.

The suspension includes offset parts introduced in the Unimog which gives extra clearance over obstacles. The wheels are large and fairly rubbery so are good for dealing with surfaces.

Interestingly the set uses separate motors to power the front and rear wheels. This simplifies the mechanics significantly, and is more akin to what future electric vehicles will be like.

Minifigures

No minifigures come with the set, but I have added a monkey to the front grill of mine.

The build

The build was disappointingly straight-forward. I did expect it to be more difficult, but there is very little in the way of mechanicals compared to say the super cars.

The completed model

After the disappointing it was a surprise at how addictive it is to play with the vehicle, creating obstacle courses for it to navigate. I'm in fact enjoying it so much I'm considering buying another so I can keep this one built, and use the other for the parts that I want.

I plan to take the completed model home with me and let my five year old at it. He has loved my previous remote controlled models, and this is sure to please him.

Summary

A straight-forward build leads to a very enjoyable completed model.

There is good scope for customisation. I have already mode the bonnet and tail-gate openable, and added a monkey to the front grill. Future customisations include adding hunters lights, and an RPG, and a lo-range/high-range switchable gearbox.