08 sierra grill block
 

well here is my prototype. If I see any gains I'll make one out of sheet metal.

Looks good!

well went for my first drive with the block on, and going up hills the truck seemed like it lacked power. tranny temp was also climbing to 170 degrees. Pulled over removed the block for the rest of the ride, and temp steadied around 145 degrees. Any suggestions? Would cutting some slits in it still provide an aerodynamic advantage or is a truck to big to have critical airflow blocked.

A couple of questions,
Where is the engine intake and where is your trans cooler located.

I know on my V8 dakota I need to have it off in the summer. I have a full block going in the winter (below 40's all the time) with no problems, and DID see a difference, especially in the warmup times.
I think if you have a transcooler in your radiator, you NEED to have some flow though. Maybe just keep the bottom inch or two open?

My dad's Ranger has a transmission cooler in the front grille, in front of the main radiator. It's probable that you covered that. Search for it, give it some air, and you'll probably do better.
Best of luck!

That is what I was thinking. Modern engine management when it sees trans temps to high will start shutting down horsepower to conserve the life of the trans. Overheating a trans will kill it rather quickly. I have found trucks more sensitive to this than cars as they are designed to actually carry a load, instead of just passengers.

GotMeHooked, do you have this grille?
http://image.trucktrend.com/f/937887...ont_grille.jpg
If so, just block off a few of the bars (like, the outer 1/3rd on both sides, and the top and bottom all the way across.)?
If not, then I'm probably not all that helpful :D

This isn't my thread, it's gotmehooked's

I know, I edited it. I don't always herp when I derp, but when I do, I herp derp.
:)

170
 

170-degrees is a good temp for the tranny.You might record your ambient temps on the days you test and build up a database for your rig.
Racers try to pre-warm all their lubes before the race to get everything to equilibrium temp and minimum viscosity to extend their range between pit stops.

I do have that grille. My air intake is by the passenger wheel well, and trans cooler is right in front behind grill.

Personally I would block off everything except a 3x4" slot in front of the trans cooler.