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Worn valve body bores cause harsh shifts, slip, and pressure inconsistencies that no amount of solenoid replacement fixes. Sonnax bore-fix kits machine out the worn bore and install an oversize sleeve + new valve. 4-6 hours bench time per kit, but extends the rebuild life by 100K+ miles.
Part You Need
Sonnax Valve Body Sleeve Kit
Step-by-Step
- 1Remove valve body from transmission (assumes transmission is open / on bench).
- 2Clean valve body in mineral spirits or solvent tank. Remove all old fluid and varnish.
- 3Identify the bore Sonnax kit addresses (each kit fixes a specific bore - 1-2 accumulator, EPC, etc.). Confirm part matches application.
- 4Set up Sonnax-recommended reamer in drill press. Use cutting fluid throughout the operation.
- 5Ream the worn bore to Sonnax-spec diameter. Take light passes - do not heat the aluminum.
- 6Test-fit the Sonnax sleeve. It should slide in with a slight press fit. If too loose, the bore was over-reamed - bad day.
- 7Press in the new sleeve using Sonnax-supplied tooling. Verify it bottoms out at the correct depth.
- 8Install new oversize valve in the sleeve. Verify smooth movement, no binding.
- 9Reassemble valve body with new gaskets, separator plate (if included), and torque all valve body bolts to spec.
- 10Reinstall valve body in transmission. Complete rebuild as normal.
- 11Test pressure on first start - Sonnax-rebuilt valve bodies usually run 5-10 PSI higher than stock. This is normal.
Sonnax kits are not interchangeable - each one targets a specific valve body bore on a specific transmission. Verify the kit matches your unit before reaming anything. A mis-reamed valve body is a $300 mistake.