Hi all,

I am the proud owner of a 99 CC Long bed and love it but am not very happy with its performance pulling my camping trailer. I have a full K&N cold air intake and that is it for modifications

I have searched the threads trying to find answers but no luck. My goal is to swap gears but dont know wich way to go. I plan on replacing my tires this summer to 315/75/16 brand not yet decided. With this size tire what gears would be reccomended without loosing the use of O/D? My wife comes from a family of PSD owners and we went from a 6.0PSD to this truck long stor short she has already started with the whole "should of just kept the powerstroke" bit and I really dont wont to loose this argument with her
The trailer is a 2004 Keystone Cougar its a bumberpull 32FT loaded with everything and extra water it tips the scales a hair over 10K. I live in Northern UT and steep MT passes are a constant Any help you can give me would me greatly appreciated.

 

Send me an email or PM and Ill be able to walk you through a few things.

 

Might want to consider going to 4.56 for gears with a taller tire. I have a 1999 also, it has 3.73, most likely yours does too. Get custom tunes from Mike at 5star Tuning. I ordered mine yesterday. Can't wait!

 

well Mike must be good, I just ordered mine about 30 minutes ago. It will come with his Y pipe replacment hopfully it will help. would the 4.56 gears allow O/D?? The new gears would run about 1100 once installed. From what I have seen the tuning from Mike really helps so hopfully It will keep me satisfied till the pocket book fills up for the gearing.

Im at the low end of the learning curve when it comes to the v10 but Ill catch up soon enough.

 

Overdrive will work regardless of the gear ratio in the axles. However, the final drive ratio will be higher with the 4.56 than with the 3.73. In other words you will see more rpm for any given speed. Overdrive just means that the transmission output (rpm) is higher than the engine input rpm. I am contemplating gears too. gets a little spendy on 4wd with two axles to change. The general consensus on this board is that the 6.8l should have a minimum of 4.30 with stock wheels/tires. With a taller tire, 4.56 would probably be better. That was the ratio I was looking at.

 

Your original post is a little confusing to me, by "35/75/16 do you mean a 35" tall tire? If so you would want to upgrade your rear gears to 4.88's, with 35"s and 4.88's your effective ratio would be 4.39. The factory 4.30 gears are considered to be the optimum gears for towing with the V-10. The deeper gear allows the 6.8 to rev a little higher to where the motor makes it's best power. If you are looking at 35" tires on 16" rims you may find that they don't make for the best towing setup, thats a lot of sidewall to remain semi-stiff to keep from squirming while pulling heavy with high trailer tongue weight like yours.

 

As far as the Overdrive portion of my question go's, I brought that up due to a suburban I had re-geared and it was constantly going in and out of overdrive it was horrible.

The Tire Size 315/75/R16 was a request from my wife. she thinks the current tires are a bit small. I am happy with the 285/75/R16 that I currently have on them. If I am listing the tir size wrong y al means anbody correct me. I just read what was on the side wall.

WE3ZS is there a formula for finding the effective ratio? That would be somthing I would like to write that down for future use. For anybody that has done teh gear swap what did it end up costing you? is 1100 a good ballpark figure?

Thank you for taking the time to reply hopfully this subject hasnt been beat to death

 

Sorry about the tire size confusion but in your original post the '1' is missing from the '315'.
As far as Tire size/Gear ratio calculators there are plenty available online, I use this one 4Lo.com :: Tire Size Change, New Gear Ratio Calculator You will need to have the tire size in inches, try the manufacturers website or Tirerack.com's listings Tire Search Results
If your truck is a 2 wheel drive then yes $1100 sounds like a fair deal for a gear swap, if your rig is a 4X4 and you got an $1100 quote for both diffs post the guy's info here and he will get more work than he can handle!
No problems here, happy to help with something I'm familiar with. I just bought a set of axles for my EXcursion with 4.88 gears and will be installing them with a set of 35" tires, that combo will bump my effective ratio up from the current 3.73 to a great towing ratio of 4.39.
A higher numerical ratio should allow the truck to stay in OD more as it will be keeping the RPMs up and making better power (and delivering that power better to the ground).

 

Thanks for the link. The 1100 dollars was just for parts I would be doing the install with the help of my father inlaw. I will wait for the SCT tuner to show up from mike at 5 star tuning and go from there. My wallet isnt very padded right now so It comes down to wishing in one hand and you know what in the other. I was able to aquire a set of PI heads along with upper and lower intake parts. not a bad haul for a saturday thanks to car-parts.com

Getting the parts is not as hard as I thought now I just have to figure out what the heck Im doing. probably opening a can of worms I dont want to be dealing with right now but such is life.

 

2 ways to go. Gear it real deep and use 3rd and O/D, or not so deep and use 2nd and 3rd.

I have 315/75-16 with stock 4.30's, so that is what my input is based on.
She will hold O/D on the flats when towing our Nash, but lock it out on the hills. And need to use 2nd on steeper high climbs like Donner. 2nd at 3500 rpm is still relaxed and results in a nice comfortable 50 mph climb. Yeah, it will rev higher and go faster, but 50 is enough to not be a road hazard and is more relaxing.

I thought about 4.56, but that would make 3500 in 2nd closer to 45. And I'm not sure she could pull 3rd on the steep grades. 4.88's would be a bit better, but I fear not enough - leaving a hole between 45 and 55 on the steep hills. So if I was to change, I would actually go all way to 5.13's. Maybe even 5.38's if my trailer was heavier.

And do follow through on your thoughts of PI upgrade and custom tune from Mike. The boost at mid to higher RPM's is VERY noticeable.

 

The tuner will help a bunch. Ive only towed my trailer once with the tunes, but once was enough to convince me. Not to mention the power when not towing, and it is just the 87 perf/tow tune for now .

 

Good info. I will be patiently waiting for the tuner you guys have got me excited. any recomenations on a brand for the gears. thanks to mwsF250's info I have everything I need to do the PI head swap. the way the weather is going out here in Ut I will be loading the trailer up for a weekend trip as soon as the Tuner from 5star shows up. How long did it take you guys to get you tuner from the time of order? From the way everyone talks about Mike He has to be one bizzy Dude.

I requested his three 91 octane tune Econ/Performance/Towing is anybody using these? 91 octane is 13 cents more here but I figure the gains will be worth it. I can careless about milage just as long as I can semi keep up with my father inlaws 7.3 PSD when we are headed for the hills.

Yall are great thanks so much for the info, I hate to sound like a begger but feel free to keep throwing the wisdom my way, sounds like your guys input will save me the trouble of a few poor upgrade choices.

 

4:88's...

esp. with a 315 tire on a 99 non-PI V10 like you have..

if you go with 4:30 or even 4:56 your gunna wish you went 1 more set of gears deeper in short order. once you hitch up that trailer.

 

The tuner shouldnt take more than a couple days to get there. It takes 10 minutes to flash the truck then give it a try. Follow the instructions.

 

Well I will be picking up some 4:88's. Are most folks going thru Ford to get them or is there another source that anyone can recomend?