I take it does this in any gear (sounds like it in your description) - classic case of the transaxle not fully decoupled from the engine.
That could be an issue related with the clutch, pressure plate, shifter linkage, slave cylinder, or transaxle itself (bearing, guides, syncros).
Since it was fine before and that you got it repaired - sounds to me like a botched clutch replacement job. First mechanic might have reused the old bolts (not recommended), didn\'t torque them down correctly, mis-aligned the clutch pressure plate, used too much or the wrong grease on the main pivot points, etc.
Fluid in the reservoir should be clear to a light amber color. The real way to check it is through chemical testing - but given that most owners cannot get access to those testing supplies, changing the clutch master cylinder and brake master cylinder (both take DOT 3 brake fluid) is good insurance against problems down the road. Moisture contaminated fluid can damage the seals on the clutch slave cylinder - which will effectively make clutch non-operational (cannot pull away from the flywheel), same with air in the clutch lines. Just like with the brakes - air will cause a spongy pedal feel and poor operation.
I take it the second mechanic fixed it? These transaxles are pretty stout in most normal instances. Not sure if they offered to let you have your old parts back - but if you have the disc right infront of you, you can see if there was any damage to the friction material on the clutch disc. Some clutches get glazed (shiny look) or have a \"rainbow\" color tint to them - that is a sign of overheating and/or disc contamination. Any physical damage usually indicates an aligntment issue.
2002 Corolla S, Silverstream, 1.8L 1ZZ-FE (VVT-i)
2003 Matrix XRS, Cosmic Blue, 1.8L 2ZZ-GE (VVTL-i) - RIP
2009 Matrix XRS, Blue Streak, 2.4L 2AZ-FE (VVT-i)