Anyone have experienced input about the Gear Vendors underdrive/overdrive unit on a F150? I am considering this unit for my '01 4X4 since I use it primarily to tow my 19 foot boat. I like the idea this unit can give you 7 to 8 forward gears. My truck is equipped with a 5.4L motor and a 4R70W auto trans. I realize the unit locks out in 4 wheel drive and my main thing is getting closer gear patterns to get the boat through all the elevation changes here in NM from 5000 ft. to 7500 ft. on the way to the lake. Up and down, up and down on the highway. The shift patterns on the factory trans. are just to wide, I am either chugging up the hills in 3rd or 4th gear, or engine screaming at WOT in 2nd gear if I press the pedal too far down. I don't want to go with a modified trans. fluid body or a shift kit because the shifts are just too firm for towing purposes. ( I have previous experience in this area with other trucks I owned.) A supercharger is wayyyyyyy too expensive and has all it's own issues that go along with it. I appreciate any input that can be provided about this under/over unit.

 

Just get some 4.10s for both ends. If you're towing something heavy enough to justify the cost of Gear Vendors, you could just check that diesel option instead on an F250, which will also help with the altitude...

 

What tires size and rear gears do you have?

I run 4.10s with 2wd stock-sized tires (285/60R18), and I tow 7,000 lbs. realatively easily, but I don't line at your altitude..

Lower gears make a huge difference, even with a supercharger.
Lightning guys often put 4.10s in with stock wheels/tires, so if it helps a high-power 2WD truck, you can bet it'll help yours while you are towing.

If you have tall 4x4 tires, you can go even lower with the gears.

You won't run out of revs even with 4.56 gears and stock-sized tires, which at least one person on this site has done. And he's got a blower, too.

 

Heh heh, 4 to 5 grand for the diesel motor by itself and more for the fuel to run it, I'll pass. But not to say that I haven't considered it. Just can't justify 35 to 40 grand on a 250 but hey one can always dream. As for the gearing change suggestions I have considered that but then I will be stuck with them for when I am not towing and these 5.4 motors like gas as it is. I have 3.55 gears, when I bought the truck there wasn't any 3.73 axles available then in the area i live in. I found 3.73 axles only in the 7700 GVW models but the options sucked on those that were available at the time. I like the idea of the Gear Vendors cuz you can turn it on or shut it off as you please. I don't think their asking price is all that bad considering you get 7 to 8 forward gears. I know you got to shorten to the rear shaft but that's ok too. I can install the unit on my own and get the shaft shortened locally. I was looking for feedback from some one that has the unit installed and working on a F150, but I do appreciate your suggestions.

 

Forgot to mention the tire size. 265-70 on 17" x 7.5" wheels

 

Just my opinion, but I think you may be overestimating the RPM change with 4.10s.

Your tires are the same diameter as mine...here's my RPM at various speeds, yours will be the same.
https://www.f150online.com/forums/sh...d.php?t=263323
A few others who made the swap also posted in there.

My MPG is unchanged so far as I can tell, and I went from 3.31 to 4.10s.
Truck generally drives better all around - towing and not - with the shorter gears.

 

Hmmm, more food for thought. Thanks for the point to the thread. I would be interested in some MPG numbers from you while towing at 65 to 70 MPH. I get 12 no matter what when towing and 10 if I'm in a hurry, so I try not to be in a hurry LOL. I also see that your Expy has a blower? Do you have another truck or is that the only one?
On second thought I don't know that the MPG numbers from you would be meaningful to me cuz you live at a much lower elevation than me and you have a blower? Yeah, changing both diffs to 4.10 would be a lot cheaper than the Gear Vendors but I'm just wondering about how much of a change in MPG it would mean. I got rid of a much better truck cuz it only got 7 to 9 MPG when towing - I couldn't afford to feed it all the time. Thanks again for your input.

 

Gear vendors are like $3k, IIRC. As of today, diesel is cheaper than 87 where I'm at.

You're probably never going to get that investment in gear vendors back in mpg savings. 4.10s will probably make you eat gas 1-2mpg worse than stock.

Either way, I don't think the gear vendors themselves will save you much fuel on your truck. It's still going to take the same amount of fuel to motivate your truck. The way I see it, the only reason to get those are if you're towing so much weight your truck has trouble moving.

 

Yeah I know I am gonna have to feed the beast when towing, but the way I look at it is I can get up and down the hills better whether its a Gear Vendors or 4.10 gears. I'm not looking for the fuel improvement while towing scenario, I'm looking for pulling power. Guess I will run some costs on a 4.10 changeout and maybe look into getting a used Gear Vendors on Ebay. I have never seen diesel cheaper in the last 5 years than any grade of gas here in the NM, CO, TX, OK, AZ area it's always higher than premium.

 

I get about 9mpg the blower and 3.5 tons of toys in tow.
Not great, but not too bad considering.

When I'm not towing, I get about 14mpg.

 

Not bad at all for towing 3.5 tons of toys. I get 16 to 17 MPG highway unloaded and 14 to 16 MPG in town unloaded in warm weather. Guess I shouldn't complain.

 

I tend to take it easy when towing.

But if I get on it while I can do worse than 9mpg...but that's just wasting money. And probably isn't too good for the truck, either.