I have a 01 F-250 w/ the 7.3 power stroke. The truck runns good but gets really poor milage compaired with my last truck, 96 silverado, Ive been told that if I keep the RPM around 1800 on the hwy ill get up to 18-20 MPG. ok thats great but I really would like to go faster than 62 mph on the road.
Ive been considering changing the rear end or maybe getting a 5 or 6 speed trans put in.I dont know how a new trans will work out with the computer. I dont hink there will be any problems with a higher gear. I wondered if anyone out ther has an idea of what gears I should use and where to get it. Also how do I tell what I have in there now. Thanks,Steve

 

steve! to tell what gears are in there now do this. jack up left rear wheel make a mark on the top outside of tire also mark the top of the drive shaft at the rear end u joint. now u will need some help, have that person turn the wheel so the mark is straight down (or 1/2 a turn) u under the truck will count the number of times the drive shaft turns completely around plus the fraction of one complete turn. if u have 4.56 gears, it will turn a little over 4 and 1/2 times, if u have have 4.10 gears it will turn over a little over 4 times, if u had say 3.76 gears it would turn a little under 4 complete turns or 3 3/4 turns. if u happen to have a posi rear end and cannot turn one wheel at a time then it is the same except when turning both wheels at the same time u will do a complete turn with both the rear wheels turning the same and at the same time.
this may be helpful. the speed u like to go on the hwy. should be at the best toqure rpm of the engine. like my 6.0 2000 rpm is best toqure factory spect. that happens to be 70 miles an hour so that is what i like to travel at, but 2 or 3 mpr one way or the other is ok.
my truck is a 03 6.0 350 the gears on it are 3.73

 

This particular vehicle is equipped with rear discs. In order to pull the axles, the calipers and rotors will have to be removed. On drum-equipped vehicles the drums and backing plate assemblies will have to be removed, as well.
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Raaj
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Welcome to the site Raajsai...


Actually,, to pull the axles themselves, you only need to remove the wheel 'center cap' and then remove the axle flange bolts and the axle/s slide right out.. Although most pull the wheel/tire so not to chance the gear lube puddle in the rim, more so for the cladded wheels. If on a ramp/runner type vehicle lift (or a chassis/frame lift) the differential can be removed with the tires on the supporting surface once the driveshaft is removed if the gear set only will be replaced, or for a ratio re gear.. Although having the driveline and truck off the ground is easier for the both removal/install..

 

Hi Steve,
Go to https://spicerparts.com/calculators/...rpm-calculator and put in your figures that you know and you can calculate your rear end ratio. I hope this helps.