ZF 4HP18

Transmission general data

The 4-speed automatic transmission ZF 4HP18 (4HP18FLA Audi) was on SAAB 9000 (4HP18Q), Rover, Peugeout, Citroen. In 1989 this transmission was updated. Later, several more modifications were released. Presently, this transmission is mainly installed on FWD Audi 100 with engine capacity from 2.0 up to 3.0. Later this transmission was updated for AWD Audi 100 and Audi Quattro. ZF 4HP18 had been used on the abovementioned cars until 1994. This transmission competed with the legendary 097-01N transmission from Audi.The design of the 4HP18 unit became the foundation for the 5-speed 5HP18 and later for extremely popular 5HP19.

Technical issues and repair guidelines

The majority of 4HP18 repair cases accounts for the transmission modification for Audi. But about the fifth part of all repair operations is related to Saab, Alfa 164, Lancia, Citroen, which have a round filter.

This transmission successfully operates with different types of fluid (LT 71141 as well as with Dexron 2 or 3). Synthetic oil is more efficient, therefore analogs of Dexton III are often used when performing complete fluid change.It is required to keep the fluid clean by means of regular and partial ATF change to reach the mileage of 300-400 thousand kilometers before the first overhaul. It is prohibited to use fluids of different colors, when performing partial oil change.

The repair kit of gaskets and seals is usually ordered when performing reassembly of this transmission. Overhaul and Precision kits are also quite popular. All compression rings and rubber elements of all burnt packages also get replaced. It is common to replace frictions of Forward and 3-4 packs.

This transmission is handed in for repair (that happens quite rare) with the complaint, typical for old transmissions: burnt clutch packages and brake bands. Common parts for replacement in this transmission are pump bushing and turbine shaft bushing. Vibrations turn down the compression ring located on support of the pump.The “cosmetic” overhaul of this transmission with worn-out torque converter sometimes is limited to the pump repair and its bushing with the pump seal replacement. Minor repair operations of electrical parts (decayed isolation and contacts) are performed without transmission removal by owners themselves.