How to disassemble and assemble a machine gun in 2 hours: step-by-step guide with photos and tips

Disassembling and assembling an automatic transmission (AT) is a task that frightens even experienced car owners. Meanwhile, with the right approach and the availability of the necessary tools, this procedure can be completed in 1.5–2 hours, saving on car service costs. The main thing is to understand the structure of the unit, follow a strict sequence of actions and avoid typical mistakes that lead to breakdowns.

In this article we will analyze the process using the example of the most common automatic transmission models - ZF 6HP26 (installed on BMW, Audi, Jaguar), Aisin AW TF-80SC (Toyota, Lexus) and GM 6L80 (Chevrolet, Cadillac). Despite the design differences, the principle of disassembly is similar. Important: if you have never worked with transmissions, practice used box before picking up the unit from the machine.

Is it worth disassembling the machine yourself? It all depends on the purpose: for preventive maintenance (changing oil, filters, seals) or fault diagnosis (jerks, slipping, errors in solenoids) - yes. For overhaul (replacing clutches, bearings, valve body) without experience, it is better to contact specialists. In this article we will look at both scenarios.

1. Preparation: tools and working conditions

Without the right tools, disassembling the machine will turn into torture. Here is the minimum set you will need:

• 🔧 Torque wrench (for precise tightening of bolts, especially critical components like the torque converter).
• 🔨 Set of sockets and socket wrenches (dimensions depend on the automatic transmission model, but usually 10, 12, 14, 17 mm are needed).
• 🔩 Ratchet wrenches with extensions (for hard-to-reach bolts in the crankcase).
• 🛠️ Plastic mounting blades (so as not to damage the seals and gaskets when separating the housing halves).
• 🧲 Magnetic tray (for collecting metal shavings and small parts).
• 📸 Smartphone with camera (fix each stage of disassembly - this will save you during reassembly).

Also prepare your workplace:

• 🪑 Workbench with good lighting (preferably with a lamp on a flexible leg).
• 🧹 Clean rags and degreaser (for example, WD-40 or LIQUI MOLY Bremsen-Reiniger).
• 📦 Plastic containers with lids (for sorting bolts and small parts by disassembly stages).
• 🚫 No dust or moisture — dirt getting into the valve body or solenoids is guaranteed to damage the box.

⚠️ Attention: If you are disassembling an automatic transmission after long-term operation without changing the oil, be prepared for severe contamination of filters and hydraulic unit channels. In this case, it will be necessary to wash all parts in kerosene or a special cleaner (for example, Mannol ATF Flush).

2. Removing the machine gun from the car: step-by-step algorithm

Before disassembling, the box must be dismantled. This stage takes up to 40% of the time the entire procedure, but you cannot skip it. Here is a universal algorithm for most front-wheel drive and rear-wheel drive cars:

1. Drain the oil from the automatic transmission through the plug in the pan (if there is one) or disconnect the cooler pipe. There will be oil hot and toxic - use gloves and a container with a wide neck.
2. Disconnect the battery and remove the air filter (it interferes with access to the box).
3. Remove the starter (it is attached to the automatic transmission housing and will interfere with dismantling).
4. Disconnect all connectors (solenoids, speed sensors, selector). Remember or take a photo of their location!
5. Unscrew the torque converter mount to the flywheel (usually 4–6 bolts). This will require turning the crankshaft to gain access to each bolt.
6. Suspend the engine on hoists or a jack (if the box is removed along with the engine, as on some models Volkswagen).
7. Unscrew the automatic transmission mounts and carefully slide the box back, removing the input shaft from the clutch with the torque converter.

On rear wheel drive vehicles (eg Toyota Land Cruiser 200 or Mercedes-Benz G-Class) you will additionally need to remove the driveshaft and transfer case (if equipped). On front-wheel drive (for example, Honda CR-V or Ford Kuga) drive shafts often get in the way - they need to be removed from the differential splines.

Drain the oil from the box|

Disconnect battery|

Remove the air filter and starter|

Disconnect all electrical connectors|

Unscrew the torque converter from the flywheel|

Suspend the engine (if necessary)|

Prepare a trolley for transporting the box -->

3. Disassembling the machine: from the crankcase to the valve body

Once the box is removed and placed on the workbench, you can begin disassembly. Let's start with the external elements and gradually get to the insides. Important: don't put in too much effort - if something does not come off, check that you have removed all the bolts, or use a penetrating lubricant (for example, PB Blaster).

Disassembly sequence:

1. Remove the pan (unscrew the bolts around the perimeter, carefully pry them off with a plastic spatula). Inside you will see a coarse filter - it needs to be replaced or washed.
2. Remove the valve body (it is secured with 10–15 bolts). Be careful - there is oil inside that can spill onto the table.
3. Remove solenoids (they are located on the valve body, usually secured with small bolts or latches). Label them so you don't mix them up when assembling!
4. Separate the housing into two halves. To do this, unscrew all the bolts around the perimeter (usually 15–20 pieces). If the case is stuck, lightly tap the connector with a rubber hammer.
5. Remove the planetary gear and clutches. This is where a magnetic tray comes in handy—small bearing balls can easily get lost.
6. Remove the torque converter (it's heavy, be careful). Check it for play and integrity of the blades.

Pay special attention valve body - This is the “brain” of the box. If you notice bullies on channels or stuck valves, you will have to restore it on a machine or buy a new one. The same goes for friction discs: If they are worn down to metal or have burnt edges, they need to be replaced as a set.

How to check solenoids without a stand?

Disconnect the solenoid from the connector and apply 12V voltage from the battery to its contacts. A working solenoid will make a clear click. If there is no sound or it is weak, the part is faulty. Also check the resistance with a multimeter: for most solenoids it should be between 10-30 ohms.

4. Diagnosis of faults: what to look for inside the automatic transmission

Now that the box is disassembled, you need to assess the condition of the parts. Here key signs of trouble and their possible reasons:

Detail	Symptom of malfunction	Possible reason	Solution
Friction discs	Burnt edges, metal dust	Oil overheating, aggressive driving	Replacement with a kit + flushing of the valve body
Solenoids	Sticking, no click during test	Winding contamination or wear	Cleaning or replacement
Torque converter	Play more than 1 mm, cracks on the blades	Shock loads, bearing wear	Replacement or repair at the stand
Planetary series	Chips on teeth, play in bearings	Natural wear or lack of oil	Replacing damaged gears
Hydraulic unit	Seizures on channels, jammed valves	Dirty oil, metal shavings	Flushing or replacement

If you find metal shavings in a tray or on magnets, this is a signal about critical wear bearings or gears. In this case you will need complete disassembly with the replacement of all worn parts. If there are few chips (a few small particles), washing and changing the oil is sufficient.

⚠️ Attention: If there are marks on the clutch discs (frictions) blue tint, this speaks of overheating due to slippage. Such disks must be replaced, even if they visually appear intact. Ignoring the problem will lead to re-combustion after 5-10 thousand km.

5. Assembling a machine: how to avoid mistakes

Assembly is reverse disassembly process, but with a number of nuances. Main rule: all parts must be clean and dry. Even a small speck of dust that gets into the hydraulic unit can clog the channel and cause the box to malfunction.

Assembly order:

1. Install a new filter (even if the old one looks clean). Filters are disposable and cannot be washed.
2. Lubricate all seals and gaskets special lubricant (for example, Loctite 574) for tightness.
3. Assemble the planetary gear, ensuring the correct position of the gears and bearings. An error here will lead to box jamming.
4. Install clutches in the correct sequence (usually it is indicated in the manual or on the discs themselves).
5. Secure the valve body and connect the solenoids. Make sure all connectors are tight.
6. Connect the body halves and tighten the bolts evenly criss-crossto avoid skew.
7. Install the pallet for a new gasket (the old one cannot be used!).

Pay special attention bolt tightening torque. For example, torque converter to flywheel bolts are typically torqued 60–80 Nm, and the crankcase bolts - 20–30 Nm. Exceeding the torque will lead to thread failure or deformation of parts.

6. Installation of automatic transmission on a car and first check

When the box is assembled, it must be returned to its place. This process is similar to withdrawal, but there are several critical points:

• 🔄 Correct positioning of the torque converter - it should “sit” on the splines of the input shaft without distortion. If you feel resistance, do not press with force - check the alignment.
• 🔧 Tightening the fasteners should be done in 2 stages: first “tighten” all the bolts, then tighten with the required torque.
• 🛢️ Fill with new oil through the technological hole (the volume is indicated in the manual, usually 6–9 liters). Use only original ATF for your automatic transmission model!
• 🔌 Connect all connectors and check for errors on the diagnostic scanner (for example, Launch X431 or Autel MaxiCOM).

After installation do not start the engine immediately. First:

1. Turn the crankshaft by hand (using the wrench on the pulley bolt) 2-3 turns so that the oil is distributed throughout the box.
2. Make sure the selector shifts to all positions without sticking.
3. Start the car and let it idle for 3-5 minutes, watching oil level (it shouldn't fall).
4. Drive 5–10 km at low speed, avoiding sudden acceleration. Then check the oil for metal shavings.

⚠️ Attention: If after assembly the box does not include transmissions or stalls, stop immediately! Continuing the movement will lead to planetary gear failure. Return to diagnostics: check the oil level, valve body pressure and solenoid integrity.

7. Common mistakes and how to avoid them

Even experienced craftsmen sometimes make mistakes when disassembling and reassembling an automatic transmission. Here TOP-5 misses and their consequences:

• 🔴 Using an old pan gasket → oil leakage and air entering the valve body (leading to kicks when switching).
• 🔴 Unwashed hydraulic unit → clogged channels and incorrect pressure (the box is “stupid” or does not switch).
• 🔴 Re-tightening of body bolts → crankcase deformation and shaft jamming.
• 🔴 Incorrect installation of solenoids → errors P0730–P0760 (incorrect gear shifting).
• 🔴 Ignoring metal shavings → accelerated wear of bearings and gears (after 10–20 thousand km capital will be required).

To avoid these errors:

• 📋 Keep a disassembly log — write down the sequence of actions and the location of parts.
• 🔍 Use a magnifying glass for inspecting small parts (for example, valve body valves).
• 🎥 Make a video key stages (especially installation of clutches and solenoids).
• 📏 Check clearances between the clutch discs with a feeler gauge (they should be within 0.5–1.5 mm).

What should I do if the box does not work after assembly?

1. Check the oil level (should be between the HOT marks on the dipstick).

2. Read the errors with a scanner - the codes will tell you which solenoid or sensor is faulty.

3. Check the pressure in the valve body with a pressure gauge (the norm for most automatic transmissions is 3–5 bar at idle).

4. Disassemble the box again and check that the clutches and gears are installed correctly.

FAQ: Frequently asked questions about disassembling and assembling automatic transmissions

Is it possible to disassemble a machine without a special tool?

Theoretically yes, but this will greatly complicate the process. For example, without a torque wrench, you risk overtightening the crankcase bolts, and without plastic mounting blades, you risk damaging the seals. The minimum you will need is a set of sockets, ratchet wrenches and a magnet to collect chips.

How much does it cost to disassemble an automatic transmission at a service center?

The price depends on the box model and region. On average for Russia:

• Diagnostics + oil/filter change: 3 000–6 000 ₽.
• Partial disassembly (replacement of clutches, solenoids): 8 000–15 000 ₽.
• Complete disassembly with troubleshooting: 15 000–30 000 ₽.

Self-disassembly will save up to 70% of the cost, but requires time and care.

What oil should I fill in after assembly?

Use only original ATF, recommended by the box manufacturer. For example:

• For ZF 6HP26: ZF Lifeguard 6.
• For Aisin AW TF-80SC: Toyota ATF WS.
• For GM 6L80: Dexron VI.

You cannot mix oils of different types - this will lead to foaming and loss of properties.

How often do you need to disassemble an automatic transmission for preventive maintenance?

Preventive disassembly is required every 100,000–150,000 km (or once every 5–7 years), even if the box is working normally. In the process they change:

• Oil and filter.
• Seals and gaskets.
• Worn clutches (if there are signs of slippage).

This extends the life of the automatic transmission by 30–50%.

What should I do if the box kicks after assembly?

Reasons for “kicks” after assembly:

• Incorrect installation of solenoids or valve body.
• Clogged valve body channels (needs flushing).
• Insufficient oil level or air in the system.
• Worn clutches (if they have not been replaced).

Solution: repeat the diagnostics by checking the pressure in the valve body and inspecting the solenoids.