i just put a new speedo cable in my car and its about 5 miles per hour fast. if i replace the drive gears will this bring everything back to normal. it still has the same 373 gears in it (never changed them). also do i have to get the drive gears for gm or a parts store. when i pull the drive gears out will trans fluid come out. thanks for any info.

Just changing your cable should not effect the reading. Something else changed. Yes, lots of fluid will come out. Have a plug ready. I think you can only buy gears from the dealer. I dont think you need to change gears if every thing worked before.