5-speed gearbox grinds as the brass synchro rings wear
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What causes "5-speed gearbox grinds as the brass synchro rings wear" on the Mitsubishi Lancer Evolution VIII (2003-2005), and how is it fixed?
A transmission rebuilder says the factory Evo VIII/IX 5-speed synchro rings are brass and wear quickly, which leads to grinding. Fix: Rebuild with new synchros; the rebuilder uses bronze rings, which it says wear more slowly.
Symptoms
Grinding when shifting, worse as the rings wear.
Cause
A transmission rebuilder says the factory Evo VIII/IX 5-speed synchro rings are brass and wear quickly, which leads to grinding.
Fix (summary)
Rebuild with new synchros; the rebuilder uses bronze rings, which it says wear more slowly. Single vendor source.
Related parts
Related build entries
Other CT9A (Evolution VIII) problems
- Recall 04V-138: wrong weight ratings on the certification label (2003)
- Recall 05V-335: turbocharger coolant hose may leak (2005)
- Recall 16V-458: front crossmember corrosion can let the lower arms detach (salt states)
- Plastic boost bypass valve leaks with age
- The MR's 6-speed is weaker than the 5-speed under high power
More for this car
- All Mitsubishi Lancer Evolution VIII (2003-2005) fitment answers · CT9A (Evolution VIII) common problems
- Newsletter archive: past issues with every new and corrected entry
Sources
- EVO - SYNCHROS — Jacks Transmissions (vendor article; read 2026-10-26; full page read)Factory brass synchro rings wear fast and cause grinds; bronze rings in rebuilds.
Summaries are in our own words. Not repair instructions; consult the factory service manual.
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