Description
Allison 1000 / 2000 / 2400 Oversized Control Main Relief Valve, Sonnax 37000-19.
Fits ’00–’15 units only.
Tooling:
- F-37000-TL19
- VB-FIX
In ’00–’15 Allison® 1000/2000/2400 units, wear in the control main relief valve bore can cause or contribute to reduced control main pressure to the shift solenoids and reduced A & B trim pressures. The control main relief valve limits peak control main pressure and is always active when the vehicle engine is operating. In action, the valve reacts against a stiff spring outboard using small diameter spools inboard to limit contol main circuit pressure. The combination of a stiff spring and small valve spools creates significant valve side loads which can wear the valve body bore. As bore wear becomes excessive ATF is allowed to escape into the exhaust backfill circuit or directly to the sump and critical pressure is reduced to the shift solenoids and A & B trim valves causing shift issues.
- Hardcoat anodized aluminum valve combats premature wear
- Added annular grooves to reduce wear rate
Symptoms:
- Shift concerns
- Loss of shift solenoid control pressure
Cause:
Worn valve bore or valve spools allow critical control main pressure/trim signal pressure to escape to sump or adjacent circuits, resulting in various shift complaints.
Correction:
Restore proper hydraulic control by refurbishing the bore and replacing worn parts with Sonnax oversized control main relief valve.
