I will be upgrading from 285/75/16 to 315/75/16 tires and was wondering if 3.73 gears will work (my ex has a bone stock v10). Eventually I will got to probably 4.56 but cant afford it right now. I pull a 6500lbs travel trailer. I don't mind if it will make it a little slower I just don't want to fry the tranny. Thanks for the replies. (where do I put all my vehicle info so it shows on each post?

 

It will be harder on tranny because it will put you in and out of od all the time. If diesel I'd say deal with it but I think you'll be unhappy with the gas engine. It will live for a long time like that but your truck will have less power off the line and will be hunting between 3rd and od on the highway.

 

Bad on the trans (depending on towing conditions: terrain).

In your signature.

 

On year 8 of 315's and 3.73's. I don't tow often nor heavy, so not a big deal. At 65mph the engine runs 18-1900 rpm. Has enough 'get up and go' for me.

 

I have 305s on a stock V10 (02) now, I want to bump up to 315s... should I get a leveling kit or a small lift, or will stock work?

I don't tow much at all, and if I do it's short distances, so gearing shouldn't be an issue, right?

Thanks!

 

i run 37's in my v-10 with 3.73's i tow about 4500lbs in a snowmobile trailer...does fine. does fine driving empty as well. its not a race truck but its the biggest suv ever made. do you expect it to be? no info on tranny life as i dont drive mine enough to know if i hurt mine early. i was concerned about it as well when i added 37's read a bit got mixed answers did it anyway and i would do it again.

 

The V-10 loves deeper gears, Period.
I've never been to Oregon, Southern or otherwise , but I think you guys have a few hills out there don't you? 6,500lbs isn't a super heavy TT but I think if you will be pulling any substantial hills with it you will be less than impressed with the effective 3.36 ratio the 315s (35") will provide. I'm sure it will pull that load and get you to your destination but there will be a lot of downshifts and higher revs on the grades. And because of that the MPGs will suffer. Deeper gears will change all of that. With my gear change I have seen a towing mileage improvement of 2.5+ MPG. Old trailer was a 9,500lb TH and with 3.73s and stock 31.5" tires we saw 6.5 to 7.5 MPG, now with 4.88s and 35" tires (effective ratio of 4.39) we are seeing 8 to 9.25 MPG pulling the new 11,000lb TT.
I would strongly recommend that you get a good trans temp gauge to keep an eye on that very important item. I use a stand alone trans temp gauge but there all sorts of apps that can also display that info as well as several other parameters. I think that everyone that tows any decent loads should be watching their trans temp and be aware of the limits and corrective actions of high readings.

I'm not sure but I think you may need to have a minimum of maybe 25 or so posts to setup your signature and have PMs turned on.

 

Alex, 315/75R16 tires are about 35" tall and will not fit on a stock 4X4 EX front without some sort of leveling/lift.

 

And even then you'll need to pull back the inner plastic fenders and expect a little rub on your front leaf springs.

 

Sean, it's all those kids destracting you

I couldn't stand the 3.73's with even with my 285's and zero towing. I went to 4.30's. If I still had the V10 and wanted 35's I would have to agree with Tommy on his choice.

 

Now that's the truth Michael. 1 son, 1 friend of son, 2 grandsons, 1 son-in-law.

 

Thanks for the replies. There are a lot of hills in southern Oregon for sure. I just got my lift kit today so once I install it I think I will get the 315's. I will definitely change gears but it prob won't be for about a year.

 

I'm not overly excited about 3.73's with stock tires so i can't imagine it with that large of a tire. Good luck!

 

Think about it like hauling around 4k lbs all the time! I would regear, there is a reason Ford didn't offer 3.30 gears from the factory! You won't be happy towing that kind of weight with 37's and 3.73's!

 

So, get a small lift then? I *think* it has a 2" level on it already (I bought it used).

The 33"s look like stock tires under it because of it.

There definitely LOOKS like there's plenty of clearance for a bigger than 33" tire.

I'll get a pro to look at it before I break something...