Bigdad, have you ever hit the scales? You're probably at 5000 pounds over the rear axle.

A WD hitch does not make up for heavy tongue weight. It does not turn 1200 pounds into 600. It is required and useful over 5000 pounds for the trailer, but is not that dramatic on the scales. It helps in bumps and dips more.

4.6 + heavy 34" tires will suck. I have the 5.4L 3.73 gears and heavy 33" tires and wish I had 4.56 gears even empty. Have you considered a hybrid TH with open cargo space? Something like the Rockwood Roo 232 or 232L.

not really...we will be looking for a few year old used one as you can pick them up so cheap right now. I am not totally opposed to those style but they arent my first choice. I think Im gonna start by gearing it and rebuilding the factory ls when its apart. from the sound of the other posts on here it will be like a whole new truck! I just need to decide to go with 4.10s or 4.30s as I really dont want to over do it, but with a trailer that heavy it needs all the help it can get!

What axle ratio do you have now and how many miles do you drive per year?

it has a 3.55LS stock (8.8). I prob between 15-20K per year on it...used to be a lot on the freeway but not to much anymore (that may change next year when I transfer though). I was looking today and it is only turning about 2K at 80mph! the speedo is sopposed to be corrected but I think it might be a bit high. I typically drive about 75mph sometimes 80 on the freeway and dont want the thing spinning too high, but then again I dont even remember where it was originally since its been so long since it has had stock size tires on it.

4.10 would be a good gear for you. The 4.6L makes peak torque somewhere around 3500rpm. It just costs more fuel.

You can always keep the 3.55's and turn OD off when towing (which you should do anyway).

I've only got 31" tall tires and only haul a #5000 'soaking wet' TT and in third, I'm pulling less then 2500 rpms going 60 mph... With 34's, #7000 trailer and a low torque 4.6, I don't know about that????

Mitch

ya I atleast want to do 4.10's even for eveyday driving...i think the truck will drive a lot better and the tranny will thank me! I just dont wanna go with 4.10's and regret them not being enough, or vice-versa with the 4.30's. Also it sounds like anywhere from 2500-3K is safe and makes enough power to cruise at 60-65 while towing so that is what I think Im shooting for

I don't think there is a 4.30, but maybe that's for the 9.75" gears. 4.10 or 4.56. I'd love 4.56 with my combo (5.4L 33" tires), even for DD.

Yeah, I'd check on the availability of 4.30's for the 8.8 diffs.... Something in the back of my head says that they don't have them for the 8.8's... If you have 4x4, you will need to do the front too, and maybe that's where the 4.30's don't exist, because they have to be a different grind up front?? I think they call it a 'reverse cut' gear for up front?

Then it's either 4.10 or 4.56... With the 34's, I'd personally go with the 4.56's and not look back! :)

Mitch

thanks for the responses guys! Im only 2wd and with the 8.8 which I think is actually the only combo they make the 4.30 ratio for...I think its probably a ratio used by mustang guys. I would think 4.56 is overkill but what do you turn rpm wise on the freeway at 60-65 and at 75? I will never get bigger tires that what are already on it (atleast if its still a street truck) so I really just dont want the thing to turn too many rpm. Im gonna try to go play with my truck on the freeway and write down what rpm's Im at certain speeds and see if I can calculate where it would be with the other ratios and see what looks like it would work best.

a quick calc from here http://www.bncoffroad.com/tire_gear_cal.html

Shows that at 65 mph with 4.56 gears you'll be spinning at 2,929 rpms in third (1:1) in OD, it will be about 2,050 rpms (.7:1)

Mitch

where do you guys mount your brake controllers? I am thinking of putting it in the little cubby below and to the right of the steering wheel so it is kinda hidden and wont get in the way. Also I need to get the harness to plug into the oem plug and not sure where to get it or what it costs.

That's where I'm gonna put mine. It seems like that's what that cubby is for anyway....
You should be able to get the harness where you get your controller.
The Prodigy has been highly recommended, and that's what I'm getting.

Letting the 4.6 rev high when towing seems a little scary to me...
Then again, I'm used to towing with a 7.5L.....

6100 lb truck, 4K camper, and maybe another 1K in the bed....2000-2100 in OD at 70...

That's the hardest thing for me to get used to with the 4.6, having to turn the OD off. My 7.5 would laugh at hills even in OD.

The only thing I don't miss about my old truck is the broken springs in the seat and the single digit MPG's....

The 7.5 is a low revving pushrod truck engine with a ton of torque. The 4.6 is a high revving OHC car engine.