Just kind of wondering what ya'll had to say about this. How well would that 3.55 pull a 14' trailer with 2 four wheelers on it? I'm sure it could handle it, but I bet the tranny would be down shifting alot. Also I have heard that some people are getting better gas mileage out of the 3.73. Any thoughts on this? Preferably I'd like the 3.73 because I want to put a little bit bigger tires on, but I've seen alot of trucks while shopping with the 3.55 and I don't know how much of a difference one would make over the other. thanks

 

IMHO, the ratios are just too close - it's almost a wash, but I guess every little bit helps.

I think tow rating is slightly better with the 3.73. You should consider a 4.10 aftermarket, or try twisting the dealer's arm & get that geasrset installed as a condition of purchase (or at least get it discounted). Worth a try .

 

The 3.73 is a bit better but I wouldn't NOT buy a truck b/c it doesn't have it. Will shift down less for sure. I have owned both by the way in the same configuration SCrew 4.4 with the 5.4.

Mpg is the same on both. Towing feels same except fewer downshiftfs on medium hills.

 

If you're going to be using your truck to tow your trailer fairly often, then I'd go for the 3.73. If not, then it doesn't matter much one way or the other.

 

I do have a pretty long commute to work, about 40 miles each way. Would there be any advantage in having the 3.55 for the long trip?

 

When I ordered my new truck I asked the dealer to change the gearl from 3.55 to 3.73 and they said they couldn't do it. If I want to change the gears what is involve and what parts need to be change? I don't want to go more than 3.73 due to fuel economy.

I'll be towing a 6k boat a few times a year and don't want to see the tranny downshifting to often.

 

I bet you could go to 4.10 gears and not loose any mpg. These are very heavy trucks and it would take a lot less fuel to get the truck moving with the 4.10's. Plus you would tow better.

 

what would a set of 4.10's cost and how bout install?

 

On a stock truck the 3.73 will pull a little harder then the 3.55's. I've had them both but I prefer the 3.73 LS. Not that long ago you were able to order the 4.10's from the factory on the heavy duty 150. If you go with taller tires you'll wish you had the 3.73's! Not that much diff in fuel savings either.

 

I have 3.55 and I pulled a 16 foot with a large lath and mill on it that weigh much more than two fourwheelers and I had no problems pulling at all. It only downshifted on decent hills and I have a feeling that it would have anyway with 3.73's the ratios are too close for it to make a big difference. I think you will be happy with eather if that is as much as you will tow.
Blake

 

my 04 F-150 had a 355 Ltd slip 5.43v and the perfrormance = to a car, for towing or hauling, the P235 70 17 hancooks and 355 LTD slip were useless, milage was not great.

I would go with the 3.73 LTD slip, or you can go with the optional 410 LTD slip if you want a tow rig.

Most Gm 1/2 tons come standard with a 410 ltd slip and smaller tires, Gm claims thiers no differance in mpg betwean a 373 and 410 on Gm trucks due to the gearing in the over drive trans.

The 410 ltd slip and low end torque of the 5.4 might be better than the 373.

 

If you have stock size wheels/tires. GO 4.56's.

 

how well would the 3.55 handle a 32" or 33" tire?? thats as big as I would go. Also how would it do with that size tire pulling a trailer?

 

I say if you do alot of towing get the 3.73 but if you only tow a few times a year go with the 3.55

 

The difference from 3.55 t o3.73 is so slight, just 5%, that it's not worth it.

True.
I went from 3.31 to 4.10s and my MPG is unchanged, on stock-sized tires (285/60R18).
Towing power is way better, night-and-day imporvement...even when not towing, it's a huge improvement.

My two bnest mods:
1. Supercharger
2. Gears
You'll find a lot of folks on this site state the same thing.

I have yet to find a post where someone went too-short on their rear gears.
People who have put shorter rears in their trucks all seem to love it.

Look at the Lightning forums.
These trucks have big power, and the guys who have switched to 4.10s all rave about it.
Just think how much of an improvement you'll see - thanks to torque multiplication - on a stock-ish truck with a lot less power.