2005 S80 Transmission problem
 

Hello, I have a 2005 S80. 102k miles. The transmission problem is when shifting from 1st to 2nd and when I slow down. I changes the fluid 10K miles ago. Then I got two messages 9 P0700' transmission control system mulfunction& P0811'Clutch slippage excessive' with engine check light. The problem doesnt happen when I drive for 10 miles, the issue starts later! Any suggestions or cheap repair? I really appreciate the help.
Thank you very much

Hi Jameel, tell you straightly you transmission is about to fail, start saving for replacement. if you really need your car to keep running you have two options left.

1: Overhauling/rebuild transmission
2: Replace the transmission with either new one or used

There is not much cost difference in above two options, if your mechanic is professional in rebuilding transmissions then go for rebuild rather getting used one.

By the way there is tons of information available about "how your transmission is failing"

Finally just to have little more time on this transmission, Try LUCUS OIL for transmission (Don't over fill) and drive at least 200 Miles. if it becomes OK, you might get few more months.

In the end, you really need either replace or rebuild.

Good Luck!

Thank you very very much for your advice. I will try using this oil. I really appreciate your help

This transmission is almost indestructible
 

Given the problems that you've described, it's likely that there is a problem with the solenoid that controls the gears shifting from 1st to 2nd. This is the one that gets the most wear and tear because the transmission always shifts between those gears after every stop. The solenoids can be replaced without the transmission requiring a complete rebuild. If the transmission fluid wasn't changed regularly, there could be a lot of clutch material blocking the passages inside the transmission and the transmission might need to be flushed out. Make double sure that you used the CORRECT TYPE FLUID.

Good luck. I hope things turn out well.