bolt size

I have a 2005 aveo and just recently I hit a pothole and the transmission popped out of 1st gear and when trying to put in any gear after that it just pops out of gear during acceleration I took it to mechanics they said motor and transmission mount were bad causing engine to sway too much causing it to pop the transmission out of gear so I replaced the mounts but it still pops out of gear so upon further investigation I noticed there is a bolt missing out of the transmission support bracket there are three bolts attaching it and one is missing this bracket is the same one that has the transmission torque mount attached to it on the lower end. would that one bolt be the cause of it still popping out of gear and if so what size is the bolt it is the one that is the lowest on the bracket.

it would be enough to allow access engine play, but i would think it would crack the case pivoting with two bolts still in there..

you replaced all three mounts? or just the rear?

I dont have the info on the bolt size handy, sorry.

If you are talking about the transmission motor mount on the right side if the engine bay I recall it being pretty large. Try a 9/16, if not its the next size up. As to the length of the bolt I think it is a 2 inch bolt.