The tranny housings on mine leave a small gap at the back aswell, thought I'd misassembled at one stage as its got a tight spot(think its gone now after running it for 2 mins up the drive).
You can see the gap in this picture.
http://www.oople.com/rc/photos/2010n.../DSC_1910.html
If you look at the pictures on the schumacher site of the gearbox, above the motor is a small purple washer spacing the front of the 2 halfs apart. This washer is not shown in the instructions and funnily enough I had two left over but didn't know what they were for. I haven't taken it all apart to put these in but could it make a difference??
Having said all of this, I love this car, it has real character, which is why I bought it. Wish I could afford another and have one as a shelf queen, its just beautiful.
