4.10 vs. 4.30

[mjarx]

Was reading posts on The Diesel Stop. How do you Tow Boss owners like them? What do you pull? Just bought a 2007 F350 FX4 (4.10) dually to pull a HR Next Level 37CK. Checking the weights & may be cutting it close. Truck topped off w/ me in it weighed 8220#. New camper will weigh close to 13k (GVWR 16,950) & I haven't even loaded it yet. Add the wife, the kids and all fluids filled, I figure I'll have maybe 300-400# for clothes & food & pots & pans before exceeding F350 GCWR. How close can I cut it without getting in trouble? I guess next time I'll research more before buying. How much $ to convert 4.10 to 4.30 should the need arise?

Thanks,

[barrelhorses]

Your 4.10 rear end ought to get the job done with no problem.

[Robert C. Strader]

Michael,

Your suspicions are well founded. The GVWR of a 37' HR Next Level is 16,950 pounds, subtract this from the Trucks GCWR of 23,500 or 23,000 pounds and your truck should weigh no more than 6,550 pounds. So you really should have bought the Tow Boss package to be legal.

I'm sure that the 4.10 rear axle ratio will pull the load, you just won't be legal. Lets hope that there are no accidents and subsequent civil suits.

Bob Strader
RV & Truck Conversion Consultants, LLC

[mjarx]

Can the diffs be converted from 4.10's to 4.30's? Is there a device that could be installed between transmission & transfer case to allow lower gear for towing yet higher gear for non-towing applications that would meet the legal criteria?

[Foxx]

I didnt think Ford's ratings had anything to do with legal stuff. So far as I've ever found, the DOT just cares about whether you're over or under 26,001 pounds without a CDL, or what weight your truck is tagged for. In all the times I've been stopped, inspected, etc when towing, nobody has ever checked my door sticker to see what my weight ratings were. While Ford's ratings are very valid in referance to how much you can safely haul, I'm pretty sure they dont have anything to do with legal.

[prograde]

Don't let this guy scare you. According to his math I would be so called "illegal" pulling 7390# w/ my F350. Come on get real. What does my factory installed hitch say? 12500# max. gross trailer weight-weight distributing. How could that be? If my GCWR is 14900# minus my truck weight of 7600# equals 7390#. Hook up and pull that fiver. Never met a DOT Commercial veh. inspector that has been interested in anything but what weight I'm licensed for on my license plates. Add the truck lic. to the trailer lic. and walla, there's what number you don't want to be over. He's not looking to make sure you have 4.30's and a Tow Boss. Their wt. ratings are there to cover their butt for warr. work. Anything to void your warr. If your pulling a 20000# trailer and it breaks you prob. won't have it towed to them with it hooked on. I've never been inspected by FMC to make sure I'm not over weight. Eric

[mjarx]

Your response poses another question. My truck weighs 7389# dry, 8015# wet. I licensed it for 8K#. Do I need to redo the lic for GVWR (13k) or GCWR (23.5k)? Camper lic's are not weight restricted here. A trailer is a trailer is a trailer.

[CaptRon]

Once more I'm going to make this statement:
Gross Combined Weight Rating is a figure determined by each manufacturer for their vehicles and is based on acceptable performance while towing a trailer...PERIOD! This is even in small print in the weight figures published by GM for their trucks.
It has no legal status even though people will try to tell you that they know someone who had been nailed by some gung ho LEO that used it to write a citation.
Also, GCWR is not posted on the truck. Only GVWR, and GAWR are listed on the door pillar. Stay at or under these, the registered weight for your truck, and the 26,001# limit without a CDL and you're set to go.
There will always be those nervous few that will tell you that you need a class 8 truck to pull a single axle landscape trailer and have the disposable cash to pay for such foolishness. You have to be comfortable with your abilities and experience to set your limits. After all how, can Hotshot haulers regularly green light the scales with a GCW of over 30,000# on F-350's? And they are doing it all over the country every day LEGALLY.

Capt Ron

[ELLIOT02]

I was told by DTS that I couldn't get a 4.30 gear ratio for my carriers,so I went to a 4.56.I have a Sterling 10.5 and your rear is a Dana 80(right?).As for the front diffs I think they are both Dana 60's.(mine is).As for weight ratings...just make sure your license plates have the appropriate tonnage.CaptRon and ProGrade are right!

[prograde]

Yes I would change your lic. to the next step up. In your case you say that 13k is the next then I would go for that. All of my F350's have been lic. for 15k. My F550 is at 33000k.Good luck. Eric

[mjarx]

Louisiana has a "B" plate for the heavier trucks. On my registration it will say 8000#. That is the weight I told them to use. Do I need to correct this & have them reissue me a 13000# (GVWR)registration?

[prograde]

Not sure how your state works, but here in MN the increments are 9000#, 12000#, 15000#, then I beleive 21000#. Here you can go in and change your sticker weight and they will prorate it for you so you don't pay for a whole year. I have done this before on my trucks and trailers multiple times. If it were me yes I would change the weight sticker. All they are worried about here is that you paying enough road tax, have the correct DL for your GCW, not over length bla, bla, bla...........

[mjarx]

Thanks for all the posts. A lot to consider.

So, if I do decide to change from 4.10's to 4.30's (1) Can it be done relatively easy? (2) How much for parts & labor?

[SmokeyWren]

[ QUOTE ]
How close can I cut it without getting in trouble?

[/ QUOTE ]

You won't get in "trouble" if you exceed the GCWR. You might get in trouble if you exceed the GVWR.

If your truck weighs 8,220 with just you in it, then figure about 9,000 when ready for the road. With a GVWR of 13,000 pounds, you'll have about 4,000 pounds available for hitch weight. And on a 17k trailer, you probably won't have that much hitch weight.

Your GCWR of 23,500 means simply that if your GCW is 23,500 or less, then you will have adequate performance when climbing a steep grade at a reasonable speed for several miles, without danger of overheating or burning up anything. So whether you need to change out the rear end is simply up to your seat of the pants. If you are happy with the performance of your tow vehicle when climbing mountains with your loaded trailer, then you don't need to change anything.

But if you want more power for dragging that trailer up from Denver to the Eisenhower tunnel, or over Vail Pass, or up The Grapevine, then you have a coupla of ways to go.

You could change out the gear ratios to 4.3 or more, as you mentioned. Disadvantage is you would have that 4.30 ratio even when you ware running around unloaded.

Or you could hot-rod the engine to produce a little more power. Gauges, intake, exhaust, and go-fast tuning mods will cost around $1,500. Disadvantage is that Ford will immediately cancel your warranty if they even suspect that you have messed with the engine tuning.

A good choice - but over $3,000 investment - would be to install an underdrive unit from U.S.Gear or Gear Venders. If they make a 10 percent underdrive, that would be equivalent to a 4.51 rear end when the underdrive was engaged.

Best of both worlds would be to change out the rear end to about a 4.56 for towing, then install the U.S.Gear or Gear Venders overdrive unit for unloaded cruising. A 20 percent overdrive is common, and that would give your 4.56 diff the equivalent of a 3.65 ratio. [img]/ubbthreads/images/graemlins/warmsmile.gif[/img]

[JW350]

[ QUOTE ]
Thanks for all the posts. A lot to consider.

So, if I do decide to change from 4.10's to 4.30's (1) Can it be done relatively easy? (2) How much for parts & labor?

[/ QUOTE ]

1) It involves a complete teardown of the diff and can take up to 1 day/diff, depending on the shop.

2) Expect to pay between $1,500 - $2,000, depending on the shop, the gear brand, and any extras like new diff covers...

There's not much of a difference between 4.10 and 4.30 gears. I think you'll be pleasantly surprised with your truck and the 4.10 gears!