TorqFix

Gearbox removal & installation: Citroen C-Crosser W5MBB 2.4 (4B12)

Step-by-step gearbox removal & installation for the Citroen C-Crosser W5MBB 2.4 (4B12): 38 steps. What to remove, in what order, and what to check after.

On the C-Crosser with the 2.4 16V 4B12 petrol engine, getting the W5MBB manual gearbox out is a bigger job than on a front-drive car because the transfer box sits in the way. Below the car, the engine lower cover, left wheel arch liner, propeller shaft, front subframe extensions and subframe all come off before the transfer box can be removed. Up top, the air filter, battery and engine control unit with its brackets are cleared, the engine wiring loom lifted out, and the gear-shift mechanism, brake servo hose and starter motor disconnected. Only then do the engine-to-gearbox bolts come out. Keep track of the many brackets and connectors, and plug the open holes so nothing gets in while the units are apart.

38 steps 1 engine code engine codes merged from 2 documented variants

🧭 Before you start

Remove the lower cover, left wheel arch liner, propeller shaft, subframe extensions, subframe and transfer box. Clear the air filter, battery, control unit and wiring loom, then disconnect the gear-shift mechanism, brake servo hose and starter motor. Remove the engine-to-gearbox bolts and lift the gearbox out. Refit all other parts in reverse, renewing the gearbox output seal as needed.

Fits: platform codes 2.4, 16V

Don't miss

  • Plug the open holes once the transfer box is out.
  • Disconnect the earth cable and engine control unit connector before removing the loom.
  • Inspect the gearbox output seal while the transfer box is off.
  • Refit all brackets and clips in their original positions.

Written for this job from the workshop steps below · TorqFix editorial.

🔧 Engine codes this applies to

4B12(SFZ)

📐 24 workshop diagrams for 4B12(SFZ)

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

C-Crosser 4B12 - W5MBB — 4B12(SFZ) · diagram 1
C-Crosser 4B12 - W5MBB — 4B12(SFZ) · diagram 2
C-Crosser 4B12 - W5MBB — 4B12(SFZ) · diagram 3
C-Crosser 4B12 - W5MBB — 4B12(SFZ) · diagram 4
C-Crosser 4B12 - W5MBB — 4B12(SFZ) · diagram 5
C-Crosser 4B12 - W5MBB — 4B12(SFZ) · diagram 6
C-Crosser 4B12 - W5MBB — 4B12(SFZ) · diagram 7
C-Crosser 4B12 - W5MBB — 4B12(SFZ) · diagram 8
+ 16 more diagrams
🔒 24 workshop diagrams for this job Ask about your Citroen 4B12(SFZ) — free or sign up free to see the drawings

📋 Procedure

  1. Remove the engine lower cover
  2. Remove the left wheel arch liner
  3. Gearbox output seal:
  4. Remove/refit the front subframe extensions
  5. Refit all other parts in the reverse order of removal
4B12(SFZ)? Steps differ between engine variants — check this job against your exact car before you commit to it. Check my car — free →
  1. Plug the holes
  2. Remove the propeller shaft
  3. Remove the brackets
  4. Remove the subframe
  5. Remove the transfer box
  6. Remove the bracket
  7. Remove the air filter
  8. Remove the battery
  9. Disconnect the engine control unit connector
  10. Remove the control unit
  11. Remove the brackets
  12. Disconnect the earth cable
  13. Remove the harness bracket
  14. Remove the engine wiring loom
  15. Disconnect the gear-shift mechanism from the gearbox
  16. Remove the bracket
  17. Disconnect the connectors
  18. Remove the clip
  19. Disconnect the brake servo hose
  20. Remove the starter motor
  21. Bolts:
  22. Remove the engine/gearbox attaching bolts
  23. Starter motor:
  24. Bolts:
  25. Transfer box:
  26. Bolts:
Workshop diagrams

Ask TorqFix about your Citroen 4B12(SFZ) — it answers with the exact sequence for that engine and the workshop drawing for each step. First question is free after a 20-second sign-up, no card.

Ask about your Citroen 4B12(SFZ) — free → or sign up free to see the drawings

Other CITROEN procedures

Who makes these pages, and how

TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.

The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.

Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.

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Workshop data on this page last updated 20 Sep 2026.