It's going into limp-in mode where it stays in second gear. If this occurs just as it's shifting to a higher gear, slippage is taking place in one of the clutch assemblies. If you find this occurs while the transmission is holding in one gear, it's more likely a sensor problem.
Your mechanic will connect a hand-held computer to read any stored diagnostic fault codes. If there are none, he can also read out the "clutch volume index" (CVI). These numbers will tell him the volume in c.C.S of fluid it takes to apply each clutch. This will give an indication of how much wear has taken place.
The good news about this design is the computer constantly updates its shift points to give you a nice crisp, solid shift, compared to older transmissions that gradually developed sloppy or mushy shifts as normal wear occurred. The bad news is that you have no warning or clue that this wear is taking place until the day comes when the computer can't overcome the wear. When the slippage occurs, the computer shuts the system down. The shift solenoid pack is spring-loaded to allow you to use Park, Reverse, Neutral, and forward will stay in second gear so you can drive slowly to a repair shop.
If you suspect slippage, you can overcome it for a while by accelerating harder than normal, then letting off the gas just before the problem shift is about to occur. Slippage is much less likely to occur when there is less load on the clutches.
Saturday, August 29th, 2009 AT 1:15 AM