head gasket or something else?
 

today on the beltway after going through the toll booth and then accelerating hard up to 70 mph, I had the rear window down and noticed a slight coolant smell. so I thought maybe it got a little warm and purged itself out of the res. well, when I stopped I checked and it hadn't purged from the reservoir. so when I got back on the beltway I noticed it again so I closed the back window and it was gone, which tells me that it wasn't coming from the engine compartment but possibly I was smelling it leaking into the cylinders and burning so then I smelled it coming out the exhaust, which is why I could only smell it with the rear window open. does this make sense? if the head gasket was toast would I smell it in the exhaust?

yes and your truck would run very rough and youd be losing coolant.

I 'm not sure if the engine would run crappy with a small leak.
Definately keep and eye on the coolant level and watch it like a hawk.

it's not running crappy but I'll watch the coolant level.

thanks.

I have almost something like your case but I found smoke under the hood and inside the passenger side I check and I think is a leak from the manifol on the passenger side!! and there is also coolant all around the transmission help please.

the smoke is probably a manifold leak juan. but the coolant around the tranny kind of scares me. I don't think mines leaking that bad if at all. I haven't noticed any level change in my coolant. your's could very well be the head gasket in my opinion.

oh yea, I noticed in your profile you were looking for the "pvc" valve. did you ever find it? if so, could you tell me where it is? hehe, just kidding.

yes there is an internal and external leak problem on them. check if its recalled juan. if its internal though youll definately know it, so no worries keiser, but pick up a spare 3.4 while theyre still cheap ;) j/k