Ford AODE 4R70W 4R75E 4R75W Transmission Line Pressure Booster Kit 4R70W-LB1 Part No. 4R70W-LB1 Unique Forward & Reverse Boost Assembly Pressure Regulator Spring Line rise control in the AODE/4R70W is different than in most units. Forward pressure is controlled by EPC oil reacting directly on the spring end of the PR valve. The OE boost assembly only increases pressure in reverse. Traditional use of a larger ratio boost valve to increase line pressure has not been an option for this unit. Sonnax has created a specially designed boost assembly that introduces a supplemental boost valve to augment line rise in forward ranges. Like other Sonnax line pressure booster kits, this special boost valve adds EPC reaction area, providing higher pressure incrementally and when it is needed the most. Combined with a spring that is approximately 10% stronger than OE and more conservative in impact than other aftermarket kit springs, this unique Sonnax booster kit gives you the best of both worlds: a modest pressure increase at the low end, with a high-end pressure that is equal to or greater than that of other aftermarket kit springs. Achieve shorter shifts and increased torque capacity without creating low-speed harshness Improved band and clutch holding capacity for increased durability Progressive pressure increase as driving conditions become more demanding All the benefits of increased line pressure without overloading the pump at idle Simple and affordable drop-in solution with no special tools or reaming required.