Hmmm. DW (that's DieselWeasel not Death Wobbles) seems to have a point.
I recently towed a heavy load up a steep hill for a long time and the temp went way up, gearbox started to sing and at the top I had P/S fluid sprayed all over the inner left wheel well. Oil pressure was way down for a few minutes but as she cooled down the oil pressure came back up to normal. My second injector was puffing out some fresh black death as well. (I got the reaming kit and bolt, fixing it this weekend)
I figure that's all to be expected when on full throttle in second gear for 10 minutes.