I've got a couple of questions if anybody can answer:

1. Is the 3.73 rear end in the Max trailer tow package the same ring gear diameter as the HD payload package ?

2. What is a heavy duty front eye bushing ?

3. Is the 9.75 in rear end the same one currently available for 3.73 gears in the 04-08 f150 ?

4. Is the 9.75 in (3.73) rear end in the HD payload package any different from the other 3.73 rear ends available ?

 

1. No....heavy duty package uses a 7 lug 10.25 semi floater...

2. No clue

3. Yes

4. the HD payload package uses a 10.25 semi floater instead of the 9.75....

 

Are you sure about that for the 09's ? I am talking about the 09's, I should have clarified that in my question. From reading the 09 order guides it appears that the 4.10 10.25 has been dropped.

 

After I read the order guides I am assuming the 7-lug HD package will still have the 10.25 rear axle, just 3.73 gears. I think they can get away with this because of the 6-spd transmission and low first gear. 4.10 were necessary in the current model because of the high first gear and lack of 2 extra gears to help get things moving and keep them moving.

 

The 3.73 is stronger than a 4.10 ratio. FORD can use the same rear and apply more power and make up the gearing in the trans. Also less driveline issues with less gear. Reduces NVH. The Tundra has a 10.50" ring gear but with the 4.30 ratio its no stronger.

 

Can you explain why the 3.73 will be stronger, I don't understand why if it has a 9.75 ring gear versus a 10.25 in the 4.10.?

 

I would say he is assuming a 3.73 is stronger because there are less teath and therefore each tooth has more metal supporting it. Otherwise, I'm unsure how it could be stronger

 

The Pinion is the weak link , The lower the ratio the smaller the pinion.
Every Race car guy, Off Road Guy Knows the deeper the ratio the weeker it is.
That is why the FORD 9" is so great it has 3 pinion bearing's so it keeps it together even with a low ratio. Thats why all the TOYOTA and GM Guys love the 9" . Strong with low gear ratio.

 

I would agree the Ford 9" is a great axle, but I don't believe it is just because of the pinion size. The removable thrid member, unlimited ratios and the fact you get axles that are held in by a plate rather than c clips drives people to this axle. None the less, it is true that the smaller pinion is weaker, but I don't think that factored into Ford's decision.

 

No It's not : COST is Factored in FORD's decision. Getting more from less.

Example's : All Modern Muscle cars have Very Tall Gears to help the rear axle live
The SVT cobra has 3.27 ratio,The Vette, Viper ect. This is a Way to Use the Weaker production rear axle (8.8"). In the old day's (before modern Trans)they would stick in a 4.10 with a dana 60 on a 9" .but no O.D for freeway use.

You Can get the LOW Gears in the Big H.D rear axle's Like the F450 -up
4.88/5.13 ect because they offset the smaller pinion with a much larger overall rear with a HUGE Ring gear.

Any Gear or Rear end shop will know above, The aftermarket gear company's will not even warranty Low gear set's because of breakage.

 

I also see the Max Trailer Tow Package comes with a 10:1 steering gear. Does anyone know what the standard ratio is without the package? What is the advantage for having a different ratio when towing?

 

Nobody want's to say or explain anything because you get flamed and told your wrong by people who know much less but think they know everything. And as a bonus for giving good info you get no positive feedback and thread dies.

 

To answer your question, the ratio is 20:1 for all F150's except for the 157" (no tow package) and 163" whellbase models. Those longer wheel base models have 17:1

 

I don't think anyone ever said you were wrong. Nor do I believe anyone ever flamed you. I just don't believed Ford change to the 3.73's for strength. And because Ford is already charging $1200 for the HD pacakge, I don't think cost was a factor either. Fuel mileage in conjunction with the new 6spd tranmission drove the change.

Now, as for gear strength in general, I agree that a smaller pinion is weaker. But you can find gear sets in a 3.50 and a 4.30 with the same number of pinion gear teeth in a Ford 9" (Precision Gear). In my example, more teeth are in contact at any one time on the 4.30, so therefore it is stronger than the 3.50 ratio. So lower gears do not always mean a weaker gear.

 

"So lower gears do not always mean a weaker gear"

WRONG ! it's not the number of teeth it's the size! but ok you win , Lower gears are no weaker. 5.71 toyota gears are just as stong as 5.71 gears in a 2.5 ton rockwell axle. I have been involved in the auto/off road bizz all my life. I set up gears,sold,been involved with the warranty side from venders,And saw thousands of broken low ratio gear set's that (precision gear) or any company will not warranty.
thats 25 plus years at 2 MAJOR 4x4 shops.

I don't take any of this stuff personal. I have many,many years under my belt and know the true answers. I like to try and share the thing's I picked up over the years from watching know it all customers like you spend money on parts they read about in a magazine. But hey we all are getting a good laugh about your idea's on axle's.

p.s : The reason all off road guy's use a super low trasfer case gear, (4:1) is because the diff's would be so week and be useless. So they keep taller gears in the axles and lower it in the t-case. DUH!