a buddy of mine just purchased a Earthquake 3.5.
he already has the Backdraft 3.5, with the stock radios can he control them both with just one?
or does he have to use seperate ones?

The DSM 2.4 can be bound to multiple vehicles with a 2.4 receiver

would that be covered in the manual?
if not, what are the steps?

it should be in the manual if not im sure you can find the info on here by using search and btw you can view the manaul right off redcats website also

the manual still has the old radio in it, not the 2.4 version.
no details on how to do this.
any help with this would be great, and very appreciated.

Try this video on the follwing page. Hope this helps.

http://www.rctoysnh.com/catalog/prod...oducts_id=4338

Also interactive manual here

http://content.yudu.com/Library/A1hu...C-2.4GHz-Radio