Back in the year 2000, the E65 BMW 7-Series was the first car to offer a 6-speed automatic transmission. They used the ZF 6HP26 transmission, which they purchased from the transmission supplier ZF Friedrichshafen AG. This well known German automotive component manufacturer was originally started in 1915 to make gears for the now-infamous Zeppelin airship. Since that didn’t go so well, they eventually moved into auto parts and started making everything from transmissions to suspensions. The ZF 6HP transmission line is used in a number of different cars, and the 6HP26 transmission is designed specifically for high-horsepower applications.
What Transmission Do I Have?
6HP26 Transmission Specifications
The idea behind the ZF 6HP26 transmission was to get multiple gear ratios into a small footprint. To that end, they used a standard planetary gearset and a Ravigneaux gear assembly. 5 clutch packs handle the power transfers, and gearbox actions are controlled by a state-of-the-art (for the time) 6HP26 transmission control module dubbed the ZF 6HP Mechatronic module / Mechatronik module. Compared to the ZF 5HP 5 speed that it replaced, the 6HP26 speed transmission used fewer components and weighed 24 lbs less. Plus, the 6HP26 torque converter can achieve lockup in all 6 gears.
ZF 6HP26 Transmission Applications & Compatibility
| Model |
|---|
| BMW X5 |
| Infiniti QX56 |
| Lexus RX300 |
| Volvo S60 |
| Volvo S80 |
ZF 6HP26 Transmission Problems
6HP26 Solenoid Problems
Problem – The ZF 6HP26 uses 7 different solenoids to control the different gear ratios. When one of the 6HP26 solenoids goes bad, a number of problems can arise. Including: delayed shifts, getting stuck in a gear, refusal to go into a gear, and slipping.
Solution – Since solenoid failures can be the cause of many common 6HP26 transmission problems, the only way to fix them will be to replace the faulty 6HP26 solenoid.
6HP26 Torque Converter Problems
Problem – The 6HP26 torque converter is able to lockup as low as first gear when in Sport Mode, and this can cause excessive wear on the torque converter clutch. As a result, drivers can experience delayed gear engagements, slipping, erratic up/down shifting, transmission overheating, and unusual noises coming from the transmission.
Solution – In order to solve ZF 6HP26 torque converter problems, a new one will have to be installed. However, excessively worn transmission fluid and cooling issues may also need to be addressed.
6HP26 Mechatronic Seal Problems
Problem – The source of many common 6HP26 transmission problems is actually a small seal between the 6HP26 transmission controller (Mechatronic) and the transmission case. When it fails, the transmission will not be able to maintain the proper amount of pressure, resulting in premature failure of the 6HP26 clutches, transmission pump and torque converter clutch.
Solution – A new 6HP26 Mechatronic adapter seal will need to be installed.
6HP26 E Clutch failure / clutch failure
Problem – Clutches are responsible for helping the transfer of power from one gear to the next. They’re lined with friction material that helps them clutches to grab. These will wear out over time, or prematurely due to improper maintenance. Symptoms of 6HP26 clutch problems include slipping, delayed shifts, harsh shifts, failed gear engagement, and overheating.
Solution – In order to correct this common 6HP26 transmission problem, the transmission will pretty much have to be rebuilt or replaced.
6HP26 Transmission Specs
General – 6-speed automatic
Application – RWD/AWD/4WD
Variations – 6HP26A (AWD) & 6HP26X (4WD)
Production Began – 2001
Weight – 184 lbs – 196 lbs
Fluid Type – ZF Lifeguard A
Capacity – 10.5 qt
What Transmission Do I Have?
6HP26 Transmission Gear Ratios
First – 4.17
Second – 2.34
Third – 1.52
Fourth – 1.14
Fifth – 0.87
Sixth – 0.69
Reverse – 3.40
