Towing questions

[jribble]

We have to take an 1100 mile road trip for the holidays. I also have the need to take a small enclosed trailer. Our van will be full every seat will have an occupant, small kids not a lot of weight but still relative to the questions. We intened to rent a trailer from uhaul, unless I can find one on craigslist that I can afford. I only need about 5x8, but the only uhaul dealer in our town stocks only the 6x12. So my questions are as follow;
1 How much will a 6x12 effect my ability to climb hills and drive highway speeds. We do live in montana and will be driving through several mountain ranges.
2 How much will this affect my fuel mileage?
3 Would it be better to just find a smaller 5x8 instead of renting the 6 x 12?
We did just have the vehicle serviced, and it does have a meduim to large size tranny cooler. Fluid is red and hasnt been changed in about 15000 miles. any suggestions or information would be great.
Thanks

[gtkane]

I don't think the size of the trailers will make much of a difference, but the weight of the contents will. If you fill it with egg cartons-no problem. If you fill it with batteries-oh boy.
At any rate, taking a fully loaded van and trailer through the mountains is a tall order...even for an A/S van! Just try to keep the weight and speed down, service the transmission, and keep it in "D" instead of "OD".

[Rufus]

I would do a little homework to have peace of mind.
first and foremost, find out what your axle ratio is..
next find out what the empty trailer weighs
add the weights of all passengers...
add the weights of all the luggage...inside the van, in the trailer, and on the roof.
do you have an engine oil cooler and/or a tranny cooler installed.
consider wind drag (will their be stuff on the roof, does the trailer hang out past the van, etc)

Doing some quick rule of thumb math...
8 passengers averaging 150 lbs each = 1200 lbs.
8 passengers luggage avg 75 lb each = 600 lbs (guessing low considering it's a holiday trip)
trailer weight (empty) = 1000 lbs (total guess)
full tank of gas = 200 lbs
TOTAL = 3000 lbs

Axle ratios/towing capacity: (2 wheel drive only)
3.23 = towing not recommended
3.42 = 5000 lbs (must also have engine oil and tranny cooler)
3.73 = 5500 lbs (must also have engine oil and tranny cooler)

[handyvan]

tranny cooler and electric brakes. be very carfull, towing anything with an astro van is scary without additional electric brakes especially down mountains. I've avererage around 16 all together. your milage is gonna drop towing a trailer, i'm guessing 12.