this method a long time ago:
second trick, Truth and Reconciliation, is pretty similar. In the first area
there are two Shades..take the closest one and push it towards the higher
ground on the left (park it a slight distance from the cliff)..and proceed to
put, oh..maybe 20 grenades under it. Save one plasma grenade and stick it in
your pocket for later.
Next, run up onto the higher ground, get a coop buddy up there..jump on his
head..and then jump onto the highest ledge..position yourself so you're
looking down, directly above the Shade. Send your buddy off to trigger a
checkpoint while you're in this position.
Now, practice a bit throwing the grenade in various locations and seeing how
the Shade reacts. You'll want to find a spot that you can throw the grenade to
that will have it fly almost directly up. Next, toss the grenade there and
give yourself a moment to pause before jumping into the path the Shade will
take (a plasma grenade takes roughly the same amount of time to detonate as a
Sniper rifle takes to reload, if you need any help). You'll want to do this
just as the grenade goes off.
Since there's no chance of hitching a ride in the Shade's seat (You can only
be prompted to 'Press X to flip..'), you'll have to use it's incredible upward
force to throw you into the sky. Think of it like a catapolt.