I want to change the transmission in my 2005 montana

[peyman]

I've got a 2005 Pontia Montana. Not the SV6 model. On the websights it says that they are suppose to get 8L/100km highway driving and 12L/100km city driving. I get about 12L/100KM highway driving and I think about 15+L/100km city driving. Mine has 92,000 KM so it's still fairly knew. I haven't really inspected it to see if the air filter needs to get changed or if there is any thing else that is causing the van to have such horrible mileage. I'm gonna change the engine oil and do a transmission flush and do a tune up on it. But my question is, is it possible to remove the current 4speed transmission that is on it and install preferably a 6 speed transmission on it? if so which transmission would fit onto the current engine properly? I live in Vancouver and do lots of driving out to Kelowna and Calgary and the engine likes to rev going up hill. So I figured if I get a transmision that has more gears it wont rev so much causing me to get better mileage on the highway and in the city. I have a friend who owns a mechanic shop so changing the transmission wont be too expensive. I also was thinking of installing some aero shutter that would open and close on there own based on the speed of the car and the temperature of the car. Also would like to get some regenarative breaks and a start stop system to reduce the gas consumption of the car while driving in the city. I really like the van. It's a great size and not too heavy. I do lots of road trips with it so that is why I want it to be as fuel effecient as possible on the highway and I use it to drive around in the city. I also was thinking of installing a HHO system. Also would like to make the ride of it more comfortable, and make the interior more eye pleasing. Also my van is the 6 person seating configuration. I was wondering if the middle row seats and the 3rd row are interchangable? if so I would like to sell the 3rd row and install the same has the middle row seats.
My question is if any one out there has suggestions on how to make the van more light besides the fact of putting in a carbon fibre hood, if it is possible to install a 6 speed auto transmision or a 5 or even 7 speed transmission or even a CVT transmission, and if so which transmission would fit. If I can buy and get some regenerative breaks and a start stop function installed or just one of those. and if any one has any more suggestions on how to make it more fuel effecient besides the fact of buying another fuel effecient van. As I don't want to do this because I would have to spend more money to buy a newer more fuel effecient van so I might as well spend that extra money on making my own van more fuel effecient. Also buying a newer van I would only reduce the gas consumption by only a little bit.

 

[Steelcity]

I applaud you for wanting better mileage ,however we own one of the best mileage getting vans out there I also own a toyota sienna(08) with a 5 sp tranny and the mileage stinks ,my 03 montana gets better mileage ,apx 10% better . Just a few tips I have heard over the years to get the most mileage: of course your driving habits hard on the gas and hard on the brakes ect... tire pressure the higher the pressure the better the mileage(less road resistance) however you should not exceed the manufacturers max pressure recommendation I try to stay around 35psi , also keep your air filter clean and engine in good tune (plugs ,wires) low viscosity oil perhaps even synthetic(5w 30) . also make sure your thermostat is working correctly if your engine does not reach proper operating temp then mileage will suffer(engine will not be as efficient). I can notice a difference in my mileage in the winter as compared to the summer months . just for some comparable info i will give you some of my mileage numbers but they are in english rather that metric . summer months back and forth to work (combo of highway and city) 25 mpg and winter around 21 mpg
If you do some searching on this forum there is a thread of our members and there mpg numbers and tips for better mileage . good luck and keep us posted of anything you do to increase your mileage . Here in Pittsburgh (4/12/12) gas is $4.00 a gallon

 

[Steelcity]

here is a link to the mileage thread

http://www.pontiacforum.com/pontiac/showthread.php?t=25125&highlight=mileage

 

[melsg5]

seems to me you are looking for exotic/expensive solutions and you havent even checked if you have a dirty airfilter. Check the filter and add an additional 2 pounds to the cold inflation pressure. Remove any stuff you dont need in the interior to reduce weight. Any of your other solutions are expensive and you would never see the return on the gas dollars you might save.