Damn, my 3.55 chugs along at 75mph in 10th just fine. Maybe my motor was built by the super secret skunk works division of KTP, LOL.

I find this thread most illuminating, in that it shows up some people can tow up to the limit with 3.73 with no problem, while others find pressing a button on the gear shifter to be too cumbersome and difficult, yet another group needing 4.30 just to maintain freeway legal speeds. Most fascinating.

 

I say it can. Last week I drove from TX through AK to TN and along the Blueridge in VA up 81 and it held 10th at 76mph most of the time. Sometimes it did downshift to 9th, and when it did it was then identical to the 4.30 truck in 10th.



There is no 4.30 upcharge. Every gear is the exact same price. They upcharge for the electric locker. They just don't offer the 4.30 without the electric locker.

 

I do like the 3.55, more relaxed at highway speeds (turnpikes here aee 80mph). My truck can be in 6th gear at 30mph. It acts like a 8 speed most of the time in town it skips 2 and 4.

It has to skip gears otherwise that's a lot of shifting around town. No wonder people report the trans getting confused at these slow speeds. Mine is pretty smooth with the taller gear.

What is 4.30 owners experience in city traffic?

 

Yeah but you no longer were in 10th, that's the most outrageous and sacrilegious breech of manhood pride machismo one can do. Dang, now that you admitted to driving in 9th at one point, you might as well trade in your truck on a Mary Kay Pink minivan.

 

I love 4.30's in traffic. Stop and go drive to work gets 15.3mpg. The last 6 weeks has gotten that number. 4.30's are great moving a 9000 lbs truck.

 

4.30s with stock 31.5s are not the greatest in stop and go without a load. The truck could skip 1st gear altogether but instead it will stay in 1st for 6mph then lunge into 3rd right as you're about to hit the brakes again when you are crawling through a parking lot or in stop and go traffic.

 

You could have saved several days by going through AR rather than AK, but I'm sure it was a scenic trip.

 

lmao. Maybe I'll try that next time. ​​​​​​​

 

I get the math with the final drive ratio in each gear and how the 10 speed makes a difference vs the old 4 and 6 speeds.

My dad had a suburban with 33's and 3.73 gears with a 4 speed auto that had a .71 OD ratio. He was pulling his 30 ft pontoon boat down the highway and the engine cover came open on it. The drag from that burned up his trans which the old TH700's were not that stout to begin with.

I told him why don't you let me swap the 4.56 gear blazer axles I have in it and it won't strain your trans so bad? He said, no it will turn too many rpm's on the highway. I told him it will turn 2500 since you have 33's. I said if you don't like it I will swap them back.

So I swapped them in and it turned 2500 at 70mph. He loved them and it pulled his boat much better.

The 10 speed simulates that is what I believe the OP is trying to point out and transmissions of course are way stouter now than they were back then.

Running a 3.55 is going to transfer more stress to the trans trying to turn those back tires with a big load. 4.30 gives the trans more leverage to turn the back tires but transfers more stress to the pinion gear which in the same size case is going to be smaller than a 3.55 pinion gear. But these rear axles are engineered big to account for that.

The diesel doesn't know what is back there. It applies a tremendous amount of torque to whatever the configuration is which why they get away with a 3.31 offering.

The 7.3 which I have is a lot less torque so it takes more rpm and downshifts lower to compensate.

So I can agree with the OP.

The lower gear 4.30 is more for max tow situations as reflected by Fords chart and in my opinion is probably to apply less stress to the transmission so it will last.

 

Yep... Hahaha !!!

 

It is worth while to appreciate that some of the most vocal 4.30 only guys tow some truly massive loads, some go as high as 5k, some have such heavy towing requirements that only thing comparable is an F150 Lightning. So they probably know what they are talking about.

 

Some prob pick 4.30 knowing they are going to put 37's on their truck so that makes sense. More leverage to turn that tire.

 

How is this over 300 posts lol

 

None of the real 4.30 experts run 37s as far as I know. Some had issues driving around unloaded on stock 33s without 4.30.

 

I literally spit out some of my beer laughing when I read this.