10.7 - Steering¶
Type: Full hydraulic steering
Manufacturer: PSC Motorsports
Full hydraulic steering with no mechanical linkage: a PSC pump feeds a PSC orbital steering control valve, which drives a double-ended ram. Ram stroke is limited to Dana 44 spec by Busted Knuckle Off-Road steering stops, and the ram mounts via an Artec Industries Dana 60 ram mount cut down to fit the Dana 44. A Mishimoto fluid cooler with fan (gated by a 180 °F inline thermostat) cools the circuit.1
Component part numbers below come from the PSC FHK400TJ kit — the 1997-2006 TJ/LJ Extreme Series full hydraulic kit with a 2.75" double-ended cylinder (PSC's 40"+ tire kit).2 The orbital valve and cylinder carry over directly; the kit pump is the exception — its PK40JP2-FH bracket is Jeep 4.0L-specific and does not fit this build's Cummins R2.8.
Specifications¶
| Component | Specification |
|---|---|
| Type | Full hydraulic (no mechanical linkage) |
| Kit | PSC FHK400TJ (TJ/LJ Extreme Series, 2.75" double-ended) |
| Steering Control Valve | PSC 160cc orbital (in FHA160-S accessory kit) |
| Ram | PSC SC2227K1 (2.75" × 8.0" double-ended) |
| Pump | Cummins-specific PSC pump TBD (kit PK40JP2-FH is 4.0L-only) |
| Reservoir | Remote (included with pump kit) — model TBD |
| Cooler | Mishimoto fluid cooler + fan (180 °F inline thermostat) |
| Fluid | PSC 715 (SWEPCO 715) |
System Components¶
Hydraulic Pump¶
Pump is engine-specific — the kit pump does not fit. The FHK400TJ kit ships a PK40JP2-FH pump kit built for the Jeep 4.0L accessory drive. This build runs a Cummins R2.8, so the kit pump/bracket does not bolt up — a Cummins-compatible PSC pump must be sourced. The kit's orbital valve and cylinder are engine-agnostic and carry over unchanged.
| Specification | Value |
|---|---|
| Manufacturer | PSC Motorsports |
| Model | TBD — Cummins R2.8 pump + bracket (NOT the kit's PK40JP2-FH) |
| Flow Rate | TBD |
| Pressure | TBD |
| Drive | TBD (belt vs. Cummins gear-drive) |
Steering Control Valve¶
| Specification | Value |
|---|---|
| Type | Orbital (PSC) |
| Model | 160cc — supplied in PSC FHA160-S accessory kit |
Steering Ram¶
| Specification | Value |
|---|---|
| Type | Double-ended (PSC) |
| Model | SC2227K1 |
| Bore | 2.75" |
| Stroke | 8.0" native; effective stroke limited to Dana 44 spec via Busted Knuckle Off-Road steering stops |
| Mount | Artec Industries Dana 60 ram mount, cut down to fit the Dana 44 |
Reservoir¶
| Specification | Value |
|---|---|
| Type | Remote (included with PSC pump kit) |
| Capacity | TBD |
| Location | TBD |
Cooler¶
| Specification | Value |
|---|---|
| Unit | Mishimoto fluid cooler |
| Fan | Mishimoto (matched to cooler) |
| Control | 180 °F inline thermostat |
| Fan Current Draw | TBD (confirm fits PMU Out 8 ~15A budget) |
| Fan Power Source | PMU Out 8 (~15A, thermostat-switched) — see PMU Outputs |
Fluid Specifications¶
| Specification | Value |
|---|---|
| Fluid Type | PSC 715 (SWEPCO 715) |
| Capacity | TBD (kit ships ~4 qt; confirm system fill) |
Outstanding Items¶
- Source a Cummins R2.8-compatible PSC pump + bracket (kit PK40JP2-FH is 4.0L-only)
- Confirm pump drive type (belt vs Cummins gear-drive), flow rate, and pressure
- Confirm the Dana 44 stroke length set by the Busted Knuckle stops
- Document Artec Industries ram mount part number and the Dana 44 cut dimensions
- Confirm remote reservoir model and mounting location
- Confirm fluid system fill quantity
- Confirm Mishimoto cooler fan current draw fits the PMU Out 8 (~15A) budget
- Document hydraulic line routing
Related Documentation¶
-
Owner decision, 2026-05-30 — full-hydro kit is PSC pump + PSC orbital valve + PSC double-ended ram; Busted Knuckle Off-Road steering stops limit ram stroke to Dana 44 spec; Artec Industries Dana 60 ram mount cut down to the Dana 44; Mishimoto fluid cooler + fan on a 180 °F inline thermostat. Model numbers, bore/stroke values, flow/pressure, and fluid specs remain pending. ↩
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PSC Motorsports FHK400TJ — 1997-2006 Jeep TJ/LJ Extreme Series full hydraulic kit, 2.75" double-ended cylinder (PSC Motorsports / pscsteering.com, accessed 2026-05-31). Kit boxes: FHA160-S (160cc full-hydraulic accessory kit w/ orbital valve), PK40JP2-FH (high-flow pump kit — Jeep 4.0L bracket, not used here), SC2227K1 (2.75" × 8.0" double-ended cylinder); fluid PSC/SWEPCO 715. Smaller-tire variant is FHK100TJ (2.5" bore / 125cc valve, 35-42"). Pump bracket is 4.0L-specific, so it does not fit this build's Cummins R2.8 — valve and cylinder carry over. ↩