Volvo: Transmission not responding in forward motion but ok in reverse, volvo 850 glt, metal shavings

Question
I have a 1993 Volvo 850 GLT that all of a sudden (within hours) it stopped moving forward unless I pussh the gas to the max and it starts moving forward very slow and picks up speed to about 45 mph.  In reverse it works fine.  The car has 120000 miles on it and I just changed the transmission oil before it the problem started.


Answer
I think it's safe to assume that the fluid change was related to the problem you're now seeing.  My guess is that one of two things happened.  Either you properly flushed the fluid, but the change uncovered an existing problem, or you improperly flushed it.  Having to gas the car hard in order to move forward to me sounds like a problem with your torque converter, which sits between the engine drive shaft and the transmission driveshaft, serving as the cushion for gear changes.  These converters are filled with transmission fluid as well, but when improperly filled or malfunctioning, can cause problems with how the car moves.  Does the transmission make any abnormal sounds (like grinding) when moving?  Did anything weird come out in the old fluid (like metal shavings)?  

It's hard to diagnose a problem like this yourself once it has arisen.  The only thing I can suggest short of takeing it to a mechanic to have it looked at, is to perform the flush again, making sure you are using the right grade ATF, and making sure to do as thorough a job as possible.  If that doesn't fix the problem, I'm afriad you're relegated to having a mechanic look at it; assuming you aren't equipped to disassemble and diagnose the transmission yourself.  Good luck!