a 2g tranny will work in a 1g dsm / gvr4, but you might be better off selling the 2g tranny and buying a 1g one ... reason is 2G trannys are very desireable and are worth more than the 1g trannys because they are getting tough to find
you can put a 2g tranny in a 1g but not a 1g tranny in a 2g