Aisin AF40 loosing RPM when accelerating

[amazinjoey]

Hi!

So I've got this weird issue from my Aisin AF40 box on my Saab 9-5, so when I'm coasting and giving the car some throttle it Rpm goes up and then looses 100-300rpm...

Any idea ?

 

[Tman220]

That's just the torque converter locking.

The torque converter unlocks on a lot of vehicles with zero throttle input and remains unlocked during throttle tip-in to keep things as smooth as possible.

This is normal behavior that you just simply began to notice.

 

[JohnnyG]

If Tman is correct, it should happen at or above about 45 mph, and a quick tap of the brakes while holding steady throttle should unlock it and you should see the rpms jump back up.

Looking at the vids, I think he's right.

 

[tcp71]

Aisin U151E in the van does this. F150 6R80 is far more noticeable and looks like complete gear change while holding in 3rd gear.