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Mazda3 2003-2008 factory workshop and repair manual download

Tools & consumables (minimum)
- Full metric hand tool set (ratchets, 6–24 mm sockets, extensions), combination wrenches.
- Torque wrench (0–200 ft·lb / 0–270 N·m range) and smaller 0–150 ft·lb for lower-torque fasteners.
- Transmission jack (or heavy-duty floor jack + wide-block support).
- Jack stands and wheel chocks.
- Engine support bar or engine hoist (to support engine when trans removed).
- Breaker bar, impact wrench (use carefully for removal only).
- Pry bars / large screwdrivers (plastic prying tools recommended for connectors).
- Clutch alignment tool (specific to the DCT clutch pack / diameter adapter for the input shaft).
- Snap-ring pliers, circlip pliers.
- Press or hydraulic bearing puller (for bearings / races if replacing).
- Slide hammer or axle puller for CV axles.
- Punches and drift set.
- Dial indicator and magnetic base (for runout and backlash checks).
- Vernier caliper / micrometer for plate thickness measurements.
- Feeler gauges.
- Clean solvent (brake parts cleaner) and lint-free shop rags.
- New gaskets, O-rings, oil seals, crush washers as required (always replace).
- OEM-specified DCT fluid and fluid pump/suction tool for filling (or vacuum fill kit).
- Threadlocker (medium strength) and anti-seize where specified.
- New clutch friction plates / steel plates / pressure plates / release actuators / bearings — as required.
- Replacement bolts for any one-time-use fasteners (flywheel/drive plate bolts often torque-to-yield).
- Diagnostic scan tool capable of DCT adaptation/calibration and clearing codes.
- PPE: safety glasses, nitrile gloves.

Safety precautions
- Work on a level surface. Use wheel chocks and rated jack stands under manufacturer's lift points.
- Disconnect negative battery terminal and keep it isolated during the job.
- Support the engine with an engine support bar or hoist before removing the transmission. Do not rely on the transmission to carry engine load.
- Use a transmission jack to raise/lower the transmission; never let it hang by wiring or hoses.
- Cleanliness: clutch friction surfaces and hydraulic/mechatronic components must remain oil- and grease-free. Work in a clean area and use lint-free rags.
- Mark and bag electrical connectors and fasteners for correct reassembly.
- Follow lift capacity limits for tools and stands.

High-level procedure (step-by-step)
Note: Mazda3 DCT design and exact fastener locations vary by year/market. Use the factory service manual for bolt sizes, sequences and torque specs. This is a general complete-repair flow.

1) Preliminary checks & diagnosis
- Scan for transmission codes and record symptoms (slippage, harsh shifts, inability to engage gears, leaks).
- Verify whether the unit is a dry or wet DCT (this determines clutch pack replacement parts and fluid). Dry units have separate dry friction packs and usually no wet pump/bath; wet are oil-cooled and require specific fluids.
- Order correct parts: clutch kit (friction plates steels), pressure plates, seals, output/input shaft bearings, gear selector solenoids or mechatronic module (if faulty), new bolts, and OEM DCT fluid.

2) Prepare vehicle
- Park on level surface, chock rear wheels.
- Loosen front wheel lug nuts, raise vehicle, secure on jack stands.
- Remove front wheels, splash shields, and any engine covers blocking access.
- Remove negative battery cable and store away.

3) Drain transmission fluid
- Place drain pan under transmission.
- Remove the fill/check plug first (if present) then the drain plug to ensure it will refill later. Drain fluid fully and dispose/label.
- If wet DCT, be prepared for more fluid (engine and cooler lines may also retain fluid). Disconnect cooler lines and catch fluid.

4) Remove intake/ancillaries / wiring
- Remove airbox, intake piping, heat shields, battery tray, and any harnesses, sensors or lines attached to the transmission housing.
- Label connectors. Unclip and move aside harnesses rather than disconnecting every clip.

5) Remove drive shafts / CV axles
- Remove axle nut(s), detach lower control arms or hub as needed to free CV axles.
- Use an axle puller or slide hammer to remove half-shafts from trans splines; be careful not to damage boots.
- Secure axles out of the way.

6) Remove starter and bellhousing peripherals
- Unbolt and remove starter motor.
- Remove speed sensors, range sensors, selector linkage or shift cables, and any wiring brackets bolted to the trans.

7) Support engine and remove transmission mounts
- Support the engine with an engine support bar or hoist.
- Place transmission jack under the trans and secure with straps.
- Unbolt transmission mount(s) and crossmember(s). Lower supports carefully.

8) Separate transmission from engine
- Loosen bellhousing bolts in a crisscross pattern and remove them.
- Carefully pry the trans rearward (use a transmission alignment tool or pry at the seam with thin screwdriver) until input shaft clears pilot/bearing, and lower the transmission straight down on the transmission jack. Keep it level and controlled.

9) Disassemble transmission case and access clutch packs / mechatronics
- Place the transmission on a clean bench.
- Photograph/label orientation of internal components as you disassemble.
- Remove outer covers (bellhousing / clutch pack cover) to access the clutch units or internal clutch packs.
- If the unit has a mechatronics (valve body + electronic control unit) accessible externally, remove it per manual — greatly care with seals and bolts. If the mechatronics is suspected faulty, it often must be replaced or bench-tested by specialists.

10) Inspect and measure
- Inspect clutch friction surfaces for glazing, contamination, uneven wear and heat spots.
- Measure friction plate thickness and steel plate thickness with caliper/micrometer; compare to service limits. Measure radial and axial runout with dial indicator.
- Inspect bearings, input shaft splines, fork contact points, and the mating surface on the engine (flywheel or dual-mass flywheel) for wear or scoring.
- Check oil pump, seals, and solenoids for metal debris or clogged passages.

11) Remove & replace worn components
- Replace friction plates, steel separator plates, pressure plate springs and any wear items beyond spec. For wet DCTs, replace bearings and seals and any dampers.
- Replace all internal O-rings, gaskets, and oil seals. Replace snap rings and circlips if deformed.
- If mechatronic/solenoid faults were present, replace the mechatronics module or individual solenoids per part availability. For many DCTs, mechatronic unit replacement is common when requiring major repair.
- If you remove bearings or shafts, use press and drift to replace races/bearings. Ensure correct orientation and use service-specified torque and seating depths.

12) Reassembly notes & tool use
- Use clutch alignment tool to center the clutch pack on the input shaft precisely; this prevents misalignment and difficulty mating transmission to engine.
- Use a torque wrench and specified torque sequence when tightening pack retaining bolts and bellhousing bolts.
- Use threadlocker on any fasteners where OEM specifies. Replace torque-to-yield bolts.
- Use press to seat bearings evenly; use a driver sized to the outer race — do not press on inner race unless specified.

13) Reinstall transmission
- Clean mating surfaces on engine and transmission; install new pilot bearing/seal if called for.
- Using transmission jack, raise trans into place, align input shaft with clutch pack using alignment tool if necessary, and push forward until bellhousing faces meet. Start bellhousing bolts by hand, then torque in the specified sequence.
- Reinstall transmission mount(s), crossmember, starter, selector linkage, speed sensors and wiring.
- Reinstall CV axles into hub and transmission, torque axle nuts to spec.
- Reinstall any removed components: intake, battery tray, wheel arch liners, and wheels.

14) Fill with correct DCT fluid and initial checks
- Refill with OEM-specified DCT fluid to the correct level and method. Many DCTs require filling through specific port with engine warm, level on flat with fluid at specified temperature, or running a bleed cycle with scan tool.
- For wet DCTs, there can be specific bleeding procedures — follow manual exactly.
- Reconnect battery.

15) Programming / adaptation & test
- Use a factory-level scan tool to clear codes, perform DCT adaptation/calibration and run automatic fill/bleed procedures if required.
- Cycle ignition and run the engine in Park/Neutral to check for leaks and fluid level.
- Road test: start with gentle shifts, then perform a series of engagements across gears to check for smoothness, slippage or harsh engagement.
- Re-scan for codes after road test and correct any remaining issues.

Common pitfalls and how to avoid them
- Misidentifying DCT type: don’t assume dry vs wet. Inspect and order correct parts before teardown.
- Contaminated friction surfaces: never touch clutch/friction surfaces with oily hands or solvent; use clean nitrile gloves.
- Incorrect fluid: using the wrong fluid will damage clutch friction materials and mechatronics. Use OEM-spec DCT fluid only.
- Improper alignment: not using the clutch alignment tool causes input shaft bearing/hub damage and makes mating transmission difficult.
- Not replacing seals/gaskets: reusing old seals often leads to immediate leaks and contamination.
- Reusing torque-to-yield bolts: these must be replaced. Always follow torque sequence and values.
- Damaging electrical connectors or wiring harness: label and disconnect carefully; damaged wiring causes intermittent faults.
- Skipping adaptation: many DCTs require electronic adaptation after build; skipping this yields improper clutch engagement and erratic shift quality.
- Ignoring cleanliness when handling mechatronic: tiny metal chips or dirt in the mechatronic valve body cause erratic behavior — always clean and use lint-free towels and filtered solvent.
- Not supporting engine: failure to support engine when removing trans can cause engine to drop or cause alignment issues.

When replacement parts are commonly required
- Clutch friction plates and steels (usually always when opening the clutch pack).
- Pressure plates, springs, release bearing (or equivalent dual-clutch release actuators).
- Input shaft and output shaft seals and O-rings.
- Pilot bearing or input shaft bearing if worn.
- Mechatronics unit or solenoids (if electronic/pressure errors present).
- Gaskets and filter elements (if present).
- Transmission mount, bolts labeled as single-use, CV axle splines or boots if damaged.
- Fluid: full refill with OEM DCT fluid (quantity varies by model).

Final checks & verification
- Verify no fluid leaks at cooler lines, pan, seals and axle boots.
- Confirm engine and trans mounts are torqued and aligned.
- Run DTC scan and clear codes, then perform adaptation routine per scan tool/manual.
- Road test with progressive load, confirming normal temperature rise and shift firmness.

Notes & final advice (no fluff)
- Get the factory service manual or OEM repair guide for exact bolt torques, sequences, and fluid specifications for the specific Mazda3 year and transmission code.
- If the mechatronic module is suspected, consider bench testing or professional reconditioning — it can be costly but is often the correct fix for erratic DCT behavior.
- If uncertain about replacement of internal gears, shafts, or mechatronic repairs, consult a transmission specialist — DCT internals require precision clearances and calibrated solenoid operation.

Done.
rteeqp73

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