4.88 vs. 4.30 need help fast

[stoddo]

I have read alot on this subject but never got a good answer. I'm getting ready to order a new 08 6.4 F-550 4X4 w/189 wheel base, regular cab and an automatic tranny. This truck will be loaded half the time and unloaded the other half. When it is fully loaded I will have 10,000 to 11,000 pounds on the bed and pulling a 7,000 pound trailer. I do long haul from utah to south dakota and from utah to california, so I will be seeing a decent amount of hills. However I do alot of around town and local driving as well. I'm replacing my 1996 F-superduty (which is really an f-450) and it has the 4.30 rear end and has done o.k. but is on the third tranny. So my question is with all this said and ford just coming out with the new 6.4, which produces a ton more power than my old truck, should I go for a 4.30 or 4.88 rear end? And does anybody have any experience or knowledge on the mpg difference between the two? I'm trying to order asap so any help would be great! Also with the 4.88 rear end ford knocks the power down to 325 horsepower and 600 pounds of torque, but on the 4.30 it stays at the normal 350 hp 650 lb tq.

[JoeyCleland]

I have 4.10's in mine but completely wish I had 3.73s. If it were me personally i would go with the 4.30s for the following reasons.

1. Better Gas mileage
2. the 4.30 pinion is bigger stronger (thats why the 4.88 has reduced power)
3. More Powerful motor tune
4. Better Gas mileage

The only reason I would go with 4.88's is if I was planning on a big lift/Tires. The worst that could happen with the 4.30's is that you have to downshift on steep hills, but I doubt it with the power that puppy has.

Just my .02

Joey

[Rob]

i think i would go with the 4.30 set up.

[08F450PSD]

I would go with 4.3 rear end because 4.88 will make engine wine hard and less mpg than the 4.3. I have 4.3 in my F-450 does fine pull my 38ft TT.

[StarDriver]

No offense, but if your carrying 10,000-11,000 lbs. on the bed, I's step up to a F-650, get the CAT motor them you have a bigger engine/trans combo to handle the long hauls along with the 22.5 tires to handle the weight better.

[99gt]

According to my Ford book all 450's and 550 have the 325hp regardless of the gears. For a 550 supercab 4x2 auto with 4:30 the tow rating is 17,000lbs and a GCWR of 26,000lbs. For the same truck with 4:88 the tow rating is 24,000lbs and a GCWR of 33,000lbs. I personally have 4:88 in my truck..i'm not going to lie..at 85mph the truck is at or around 3000rpm. I know when jumping from 4:10 to 4:30's you're looking at about a 150rpm difference at hwy speeds. 4:30's to 4:88 i cant see being any more than a 200-225rpm difference. These trucks also suck on fuel...literally. My truck has around 850miles on it now and according to the computer i'm getting 8mpg..in town or on the hwy..it doesn't really matter.:censord:

[720Deere]

You will not be even close to legal with that load on a 450. Most 550s can only haul 8,000-9,000 lbs legally. StarDriver is correct, you need a lot more truck to regularly haul those loads. Depending on how the truck is equipped, a 450 can only legally haul 5,000 to 6,000 lbs.

Unless you travel on relatively flat ground, the 4.88 is the only way to go for that much of a load.

[stoddo]

I appreciate the help, this is a pretty cool resource. But in reply to the f-550 being to small I already have an international that hauls larger loads. The f-550 is so I can get into areas in farm areas and not have a huge truck to drive. I figure the 550 will weigh around 8500 pounds after I put my flat bed on. I'm a bee keeper so we just load up as many hives on the thing as is legal, so that would leave me about 10,500 pounds to put on the bed but if I go with a 4.30 rear end then I lose 1100 pounds of payload. the tires on those 550's are also pretty large at 19.5. So do any of you know what kind of mpg difference I could expect between the 4.88 and the 4.30?

[mjm]

I have a 450 with 4.88's with 3100 miles on it, mostly highway. I get about 11.7 mpg running over 65. I find when I keep it at 55-60 I get about 12.5 empty. At 60 mph I'm running at 2100+/- RPM's. If you crank out 70 to 74 mph the RPM's are over 2650.
I don't know what a truck with 4.30's would get but i can't imagine it would be huge jump in milage.

[jason1168tx]

Mine has 4.88's in it also. I use it for pulling only, either a 10,000lb boat or a 14,000lb 5th wheel. I get around 9.0 to 9.3 running 75mph and it has no problem maintaining 75mph uphill loaded. I have thought about adding a Gear Vendors overdrive unit, but at about $3500, it would take forever to pay for itself even if it improved the mileage by 2mpg, which I seriously doubt that it would.