4th Gear runs a few hundred RPMS fast for a while.

tblindt · Post by **tblindt** » 09 Apr 2012, 20:49

Sometimes and becoming more frequent my 4th gear runs a little high 70 MPH= 3000 and after five minutes or so it will gently drop 300+/- or so RPM to normal. This is starting to worry me, is this the beginning of the end?

Its like it has to warm up that 4th gear or something.

Post by **rmmagow** » 10 Apr 2012, 08:14

Sounds like a sluggish TC lock-up. Change the fluid and use Mobil-1 Synthetic ATF. Might help. This helped another car I have that started having TC lock-up issues (a Subaru)

Post by **jimmy57** » 10 Apr 2012, 09:02

The fluid temp sensor must register approx 125F before TC lock is enabled. Temp sensor bias can make it delay until an actual higher temp when sensor biases low.
Before you get too worried the car needs to be driven from cold with a scan tool and see if TC lock is occurring when trans temp is indicated as 50C or a bit above.
If the engine thermostat is sticking open it will keep ATF cooler and the delay could be engine cooling system related.

tblindt · Post by **tblindt** » 10 Apr 2012, 10:52

Thanks Guys. I'll start with the finest Mobil 1 idea and then see if it continues. Far as the thermostat Is there a way to see if its staying open too long? I do have slight temp variation. What type of scan tool are you speaking of here?

Post by **jblackburn** » 10 Apr 2012, 11:48

If you see any temperature variation driving down the road after 5 minutes, your thermostat is definitely stuck open and Jimmy's idea holds merit.

I have seen mine hold out on the torque converter "up shift" on cold mornings at 70 mph, so it does sound like it has to do with the temperature of the fluid.