Transmission Fluid for Automatic (MMT)

[Joey Li]

Hello All. I'm a new Aygo owner. It's a 2013 Aygo.

 

I understand MMT has different characteristics than typical automatic. I observed the following symptoms and wonder if changing the transmission fluid can improve.

1. Even the engine has good enough RPM, it takes a longer time than the usual automatic car to gear up and speed up.

2. On an uphill slope, the car is easily sliding backwards even it's in E gear. It seems dangerous.

 

The first thing I can think of is changing the transmission fluid. I read through the owner's manual. It only mentions the gear oil for manual transmission. For an MMT car, should I use the manual transmission gear oil (API GL-4 and SAE 75W)?

Thank you!

[Guest]

The MMT isn't an automatic, it's the same gearbox as a manual but with actuators fitted instead of the gear selector cables and clutch cable.

So you use exactly the same gearbox oil - because it's exactly the same gearbox!

BTW it's very important that you use  GL-4 oil and NOT either a GL-5 or GL-4/5 oil as the higher sulphur content of these can damage the gearbox internals.

[flash22]

Sounds like a slipping clutch to me, as above it's an automated manual gearbox

[Devon Aygo]

As flash mentions it is a manual gearbox with robotised clutch and shift actions:

"1. Even the engine has good enough RPM, it takes a longer time than the usual automatic car to gear up and speed up."

Like A manual transmission the car has to dip the clutch, shift the gear and re-engage the clutch when shifting for you, you can assist this by ( like a manual ) by lifting off the throttle when the car shifts and reapply as it engages the clutch this smooths the shift and eases wear on the clutch, as you get used to the car you can usually anticipate the car shifting, being a 2013 model you also have paddle shifts and using these can improve shift as the car will change when you command rather than when it thinks is best ( don't worry you can't mis-shift )

"2. On an uphill slope, the car is easily sliding backwards even it's in E gear. It seems dangerous."

Again like a manual you should not do this as the car will be slipping the clutch and you will overheat and damage the clutch, the car is not designed to hold you on a hill, like a manual in these circumstances you apply the handbrake and shift to neutral whilst waiting DO NOT hold the car by applying throttle, when you are ready to pull away again like a manual select a gear ( E ) and gently apply throttle until you feel the car pull on the parking brake and release the parking brake to move off.

[Joey Li]

Thank you for the explanations above. My wife's and my driving experience were fully automatic.

I was thinking to buy this small car for my wife driving kids to school. I'm now thinking I bought a wrong car for her. It may be difficult asking her to understand the mechanic of the clutch.

As it's a 2013 car drove 50,000+ miles, would you guys suggest to change the transmission fluid anyway?

[Guest]

13 minutes ago, Joey Li said:

Thank you for the explanations above. My wife's and my driving experience were fully automatic.

I was thinking to buy this small car for my wife driving kids to school. I'm now thinking I bought a wrong car for her. It may be difficult asking her to understand the mechanic of the clutch.

As it's a 2013 car drove 50,000+ miles, would you guys suggest to change the transmission fluid anyway?

Because the clutch is automated, IMHO there's no need to understand how it works. I've driven many automatic & DSG cars before this MMT one and TBH I just drive them all the same way, throttle to go, brake to slow/stop and that's it.

There's no harm changing the gearbox oil, but IMHO there's no need either so on the principle of "ain't broke, don't fix it" I would leave well alone.