ZF and their transmissions, both automatic and manual, have always been a favorite of European automakers. Their most recent longitudinal automatic transmission offering, the 8HP, continues their success with one of the most talked-about automatic gearboxes in an era full of CVTs and DCTs. From fast Jaguars to Chrysler minivans to the Rolls-Royce lineup, ZF's 8HP transmission has taken the automotive manufacturers by storm since its debut in the early 2010s, becoming the go-to automatic transmission for a large number of automakers across the globe.
BMW currently uses it in every model they make that doesn't wear an M-badge or isn't powered by electricity. The 8HP first appeared in Bentley and Jaguar models in 2012 and is still being used today. Even today's Land and Range Rovers use ZF's 8-speed auto-box. And although these transmissions are known for their reliability, there are still things you can do to maintain their good health. ZF recommends a transmission oil change every eight years or 50,000 miles, and that's a job you can tackle at home.
For this DIY, we are using a service kit for BMWs. Although the kit is for the BMW 8HP45 and 8HP70, you can apply the same basic process to servicing every ZF 8-speed, regardless of the make and model. Along with this DIY, you can follow this one if you ever need to get your gearbox into neutral while the battery is dead.
How much will it cost to change the oil in a ZF 8HP transmission in a BMW?
The kit we provide for you BMW's 8HP comes with everything you need for a service. The kit includes seven liters of ZF fluid, a new transmission oil pan that doubles as the transmissions filter, and thirteen new bolts for the oil pan. Because the transmission's oil pan doubles as the filter, the kit isn't the cheapest at $284. However, that is significantly cheaper than what it would cost for a new transmission, making the maintenance a no brainer.
A dealership will happily take on the job of servicing your transmission, but it will cost you. Expect to pay more for the parts and an hour or two of labor, at around $200/hour.
How long will it take to change the oil in a ZF 8HP transmission in a BMW?
The ZF oil change procedure is a little more complicated than a standard engine oil change. Draining the oil and removing the filter is pretty straight forward, but the filling procedure has some extra steps. You'll need to fill the transmission once, then get it to a specific temperature range to check it and fill it again. Expect the job to take around an hour to complete. ,
Parts required to change the oil in a ZF 8HP transmission in a BMW:
Tools required to change the oil in a ZF 8HP transmission in a BMW:
- 8mm Socket
- 8mm Wrench
- 8mm Allen Bit Socket
- 10mm Allen Bit Socket
- T40 Torx Bit Socket (Long)
- T40 Torx Bit (Short)
- Torque Wrench
- Scan Tool
- Fluid Pump
- BMW Filler Adapter
- ATF System Filling Tank (Optional)
- Fluid Catch Pan
Steps required to change the oil in a ZF 8HP transmission in a BMW:
Step 1: Drain the oil
Jack up the car and set it onto jack stands. Then slide under the car, beneath the transmission, and use an 8mm socket to remove the five bolts that mount the splash shield to the transmission.
Next, locate the fill plug on the side of the transmission. Use an 8mm Allen socket to crack the plug loose. After that, use a 10mm Allen socket to remove the drain plug from the oil pan and allow the transmission fluid to drain into a drain pan.
Step 2: Replace the transmission pan/filter
On these ZF transmissions, the transmission's oil filter is integrated into the drain pan. So, to remove the pan, use both the long T40 bit socket and the short T40 bit with an 8mm wrench to remove the thirteen mounting bolts.
When you remove the pan, ensure that the pan's o-ring comes out with it and doesn't remain in the transmission. Allow fluid to drip out of the valve body in the transmission for a few minutes with the pan removed. While the oil is draining, use a rag to wipe down the transmission pan's mating surface. Then take a dab of fresh transmission fluid and wipe it around the o-ring in the new oil pan.
Hold the new oil pan up to the transmission and thread in the new bolts by hand. Ensure that the o-ring in the pan properly seats into the transmission. If it doesn't seat, the transmission will struggle to pick up fluid, resulting in internal damage. With all of the bolts threaded in, use the T40 bit socket to torque all of the bolts to spec. Follow the graphic below to torque the bolts in the proper order.
Step 3: Refill the transmission with fluid
You need to fill the transmission with fluid through the plug on the side of it, just above the pan. There is no way to fill it from the top, so you'll need to use a pump of some kind to get the fluid into the gearbox. The CTA fluid pump linked in the tool list will allow you to pump the fluid directly from the bottles into the transmission.
Pump fluid into the transmission until it starts to leak out of the fill plug. Thread the dill plug back into the transmission and tighten it with an 8mm Allen bit socket.
You need to check the fluid level with the transmission fluid between 40° and 50° celsius. Start the vehicle and let it get up to temperature. Use a scan tool capable of reading the onboard sensors or a temperature probe in the oil pan to read the fluid temperature.
Shift the transmission through all the gears to activate their solenoids and get the fluid pumped through the whole system using the process below.
- Start engine
- Put your foot on the brake
- Shift transmission into "R" and "D" continuously
- Shift transmission in manual mode from 1st to 3rd and hold gear for 3 seconds
- Shift transmission in manual mode from 1st to 4th and hold gear for 10 seconds
- Select all gears in manual mode from 1st to 8th and hold gear for 10 seconds
- Keep engine speed at 2000 RPM's to ensure torque converter fills with fluid
Then, with the engine running, head back under the car and remove the fill plug. The fluid level will have dropped, so fill it once more until fluid starts to leak out. Refit the plug and tighten it with an 8mm Allen bit socket.
While you're under there, refit the splash shield and tighten its mounting bolts with an 8mm socket. Then take the car for a test drive to ensure everything is working properly.
ZF 8-Speed Oil Change Torque Specs:
- BMW Transmission Filter/Pan Bolts = 4Nm or 3 ft-lbs of torque, plus 45° of rotation