Tiptronic shifting to 3rd gear and engine goes off

[Erik997S]

Hello,

I’m new to the forum and will introduce myself shortly. I live in Belgium and have been driving my 997S for 15 years. Unfortunately, I haven’t driven it in the last two years due to long COVID. During that time, I’ve done some updates and maintenance on the car, but now I’m facing a problem that I can’t figure out. This issue arose between my last drive two years ago and now.

Here’s what I’ve done to the car recently:

• Installed a new water pump (GT3 model with a smaller wheel that turns faster)
• Replaced the thermostat (72°C)
• Installed new radiators
• Replaced the condensers
• Changed the oil and oil filter
• Added new coolant
• Replaced the ATF filter and oil (Tiptronic)
• Installed a GT3 front bumper, wing, and side skirts
• Replaced the brake pads
• Purchased an NT530 to check fault codes

I’ve checked all the connectors and fuses, and I’ve also added some high-octane fuel (98).

Here’s the problem: when I drive, the car starts fine in 2nd gear, but as it shifts into 3rd gear, the engine stops running. I’ve tried using the manual shift buttons, but the same issue occurs.

Does anyone have any ideas on what could be causing this? Any help would be greatly appreciated!

 

[Luddite]

Not got a clue, but is it possible that a gearbox oil change might require some digital monitoring and recoding... As I am digitally challenged, I could be typing nonsense..

 

[montygraphics]

have you checked for fault codes.

 

[Gizmob73]

Have you double-checked the oil level in the gearbox now it has been run?
I looked at changing the oil in my Tip and it looks like it isn't a simple fill and done process like on an engine.

 

[Bigbaddog997]

Oil level in autos in crucial but shouldn’t stop the engine in my experience. Horrible gear changes, yes.
Not in a Porsche but I’ve heard a few stories like this that were eventually traced to fuel pump issues in other makes of car.

 

[Erik997S]

Thanks, everyone, for your replies! Earlier, I had a whole list of fault codes because I checked every fuse. But after some testing, there are now no fault codes on the Tiptronic or engine, which only adds to the mystery.

Filling the ATF (Automatic Transmission Fluid) is definitely a bit of a dance, and it seems I might’ve stepped on my own toes. I recently realized that the air conditioning needs to be off during the process—oops! It’s probably logical that the biggest chance for something to go wrong would be in the work I did.

To get it right, the ATF temperature needs to be between 30°C and 40°C. If it’s too hot, you end up with insufficient filling; if it’s too cold, you overfill it. The selector lever has to be in the "P" position, the engine idling, and the vehicle perfectly level.

Here’s the exact procedure I followed, starting from the point where the ATF is released. If anyone spots where I might’ve messed up, your feedback would be greatly appreciated!

1. Jack up the car and level it on supports.
2. Pump in approximately 3.5 - 4L of oil through the charging port until it comes out of the control bore. (Don't close up the control or charging port yet.)
3. Connect the NT530 and check the ATF temperature. (The car must be in Drive to get an accurate reading.)
4. Start the engine and wait until the ATF temperature reaches around 30°C (in Drive).
5. Put the transmission in "P" and let it idle.
6. Pump or press the ATF through the charging port until it comes out of the control bore again.
7. Still don’t close up the control or charging port.
8. While pressing the brake, cycle the transmission through N, wait 10 seconds, then D, shift to first gear, wait 10 seconds, then to second gear, and wait another 10 seconds.
9. Close the control port, check the ATF temperature, and shut down the engine.

10a. If the ATF temperature is 40°C or lower, close the charging port. Done!

10b. If the ATF temperature is above 40°C, let it cool down and restart the procedure.

I’ve never heard about fuel pump problems before. I can let the engine run in "P" for 30 minutes and even rev it without any issues. But as soon as I drive and shift into 3rd gear, the engine just shuts off.

 

[Bigbaddog997]

Rechecking the fluid level seems sensible but having serviced numerous ZF gearboxes with the same filling procedure if that is what you have followed the fluid level should be ok.

 

[montygraphics]

Videos I’ve seen on this procedure they have used an electronic temperature gun to read the temp of the gearbox casing.

 

[pizzahut]

weird that it only happens in 3rd gear. wonder if it's transmission or engine related.

 

[Erik997S]

Videos I’ve seen on this procedure they have used an electronic temperature gun to read the temp of the gearbox casing.

I have a temperature gun and can also read the temperature through the CAN bus using the Foxwell NT530. Since measuring the temperature at the bottom of the oil pan might not give an accurate reading of the oil’s actual temperature, I'll cross-check it with the gun.

To ensure consistency, I’ll heat up the oil by letting the engine run longer beforehand. This way, all the ATF will reach the same temperature. Then, I’ll let it cool down before starting the procedure I described earlier.

 

[Erik997S]

I just came across something interesting about Tiptronic transmissions—not specifically Porsche, but it might still apply. Apparently, excessive transmission fluid can trigger limp mode. Limp mode is a protective mechanism activated by the vehicle’s computer system when it detects a potential issue that could damage the transmission or engine. I’m not sure if Porsche has a limp mode, but it could explain why the engine shuts off.

 

[gizlaroc]

Sounds like it could be the torque converter locking up.

If you start in sport or manual mode, you start in 1st, does it then stall when it tries to go into 2nd?

Trying to work out if it is 3rd gear that is an issue or any gear change at all.

 

[gizlaroc]

How much fluid did you drain out?

Have you actually emptied out some from the torque converter too?

 

[gizlaroc]

I would also check any hoses and the intake manifold for any leaks.

Have you removed the airbox at all?

Is the Idle Control Valve OK? Not gunked up?

 

[montygraphics]

Most of the tiptronic boxes are made by Mercedes’ so talking to a Mercedes’ specialist may help.