Anyone change fro. 3.73 to a higher gear ratio?

[bigrpowr]

I would not do 3:31.... I would do 3:55 ... Unless you don't plan on going to the track. It's gonna hurt the 330 more than it helps the 660-1320. Jmo. As for fuel mileage I gained 1.5+ going from 3:73 to 3:55 with 33" tires and track times didn't change a bit.

 

[capt dong]

My crew cab came with 3.73 it has 3.55 now and I wouldn't trade them for anything. Mileage is better and tows 11-13000 lbs great

My reg cab has 3.73 prob needs 3.31 but i'm going to try something else to help load the turbos.

Imho for a 6.4 with 35s or smaller needs 3.55 no matter what.

would you suggest 355s for even lightly modded 64s?

 

[Smokyred]

would you suggest 355s for even lightly modded 64s?

Should work fine, some came that way from the factory.

Dave

 

[AllanB]

I would not do 3:31.... I would do 3:55 ... Unless you don't plan on going to the track. It's gonna hurt the 330 more than it helps the 660-1320. Jmo. As for fuel mileage I gained 1.5+ going from 3:73 to 3:55 with 33" tires and track times didn't change a bit.

Thanks Bud, I will try out 3:55's. I am mostly just wanting to drop the rpm's down some while on the interstate running 75/80mph, and not have to pay for it at the track. I will go with 3:55's first and still might try 3:31 later. I can always change back, seeing I will still have a set of 3:55's.

 

[SouthFlstrokin']

Thanks Bud, I will try out 3:55's. I am mostly just wanting to drop the rpm's down some while on the interstate running 75/80mph, and not have to pay for it at the track. I will go with 3:55's first and still might try 3:31 later. I can always change back, seeing I will still have a set of 3:55's.

I still think the 3.31s would be a Vetter fit for a 2wd. You have less weight to move....

 

[Kind]

I would not do 3:31.... I would do 3:55 ... Unless you don't plan on going to the track. It's gonna hurt the 330 more than it helps the 660-1320. Jmo. As for fuel mileage I gained 1.5+ going from 3:73 to 3:55 with 33" tires and track times didn't change a bit.

A 2wd is a differen ball game then a 4wd. There is about 1000lbs difference between a truck like Allan's and mine vs. Godzilla.

Thanks Bud, I will try out 3:55's. I am mostly just wanting to drop the rpm's down some while on the interstate running 75/80mph, and not have to pay for it at the track. I will go with 3:55's first and still might try 3:31 later. I can always change back, seeing I will still have a set of 3:55's.

You won't loose anything at the track with 3.31's. With my 3.55's I consistently see 5-10psi less boost then most CC 4wd's on the street. It's about maximizing the power curve and our 2 trucks blow through the rpm's until top gear. In my opinion making the most of the lower gears will net a greater gain then shorter ones... As well stretching out the gears down low will aid in traction.

I still think the 3.31s would be a Vetter fit for a 2wd. You have less weight to move....

Exactly

 

[AllanB]

A 2wd is a differen ball game then a 4wd. There is about 1000lbs difference between a truck like Allan's and mine vs. Godzilla.



You won't loose anything at the track with 3.31's. With my 3.55's I consistently see 5-10psi less boost then most CC 4wd's on the street. It's about maximizing the power curve and our 2 trucks blow through the rpm's until top gear. In my opinion making the most of the lower gears will net a greater gain then shorter ones... As well stretching out the gears down low will aid in traction.



Exactly

As well stretching out the gears down low will aid in traction.
That alone would make it worth it. Unbelievable how fast it goes through the first 3 gears.

 

[Corb@CorbinShipping]

I have a set of 3.55s from my 2010 F250 sitting in the garage..... send me your 3.73s, and I will send you my 3.55s...... you are still gonna need teh bearings, seals, gaskets, etc...

 

[Smokyred]

I have a set of 3.55s from my 2010 F250 sitting in the garage..... send me your 3.73s, and I will send you my 3.55s...... you are still gonna need teh bearings, seals, gaskets, etc...

That looks like a good deal to me right there! I wouldn't pass it up!

Dave

 

[6.4psd916]

The shifting is tuning dependent, some are faster, some slower.

 

[Corb@CorbinShipping]

That looks like a good deal to me right there! I wouldn't pass it up!

Dave

yeah, I needed more gear than the 3.55s, as I was going up in tire size. Up to 35s at first, next up to 37s.... but the 4.10s were too much of a jump, as it turns out... LOL They have been sitting there since last year.... I would love to drop mine down to 3.73, but I dont wanna buy ANOTHER set of gears.... But ill pay shipping for some though!

At least when I go up to 37s, I can either stay with the 4.10s, or have another option...

 

[AllanB]

I have a set of 3.55s from my 2010 F250 sitting in the garage..... send me your 3.73s, and I will send you my 3.55s...... you are still gonna need teh bearings, seals, gaskets, etc...

You gotta deal right there. But I have got a few other things to do first. It might take 4 weeks or so before I am ready. But in the mean time if you find someone else that wants to take you up on that, don't wait on me. But thanks for the info and offer. I will sure take you up on that if you haven't gotten rid of them before I am ready. I will check on the other parts and see where I can get them.

The shifting is tuning dependent, some are faster, some slower.

Unfortunatley they are also rpm dependent lol. I have seen that the 6.4ltr red lines 1000rpm less than my 6.0ltr. Also I might be wrong, but I am betting that the guys that write these tunes. Know exactly where the peak power is in our rpm range. and probably setting it to shift just after it passes peak power/rpm. I don't really know that, just a hunch.

 

[WoodBoy]

Doesnt Smokin' Joe have 3.31s? I have 3.55s. I think late 09s and all 2010s came with 3.55s.

 

[powerlifter405]

Doesnt Smokin' Joe have 3.31s? I have 3.55s. I think late 09s and all 2010s came with 3.55s.

you are correct, he does.

 

[Smokin_Joe]

I picked up a few MPH trap speed. MPG went up on the highway / Down in city. I'm around 2k rpm @ 80mph. I'm happy with it. Seems to be harder on the trans though.

 

[AllanB]

I picked up a few MPH trap speed. MPG went up on the highway / Down in city. I'm around 2k rpm @ 80mph. I'm happy with it. Seems to be harder on the trans though.

Thanks Bud, I think I will go with the deal that Corb threw out there on the 3:55's. Then if I am not happy move on up to 3:31's. Maybe try to slide a BTS trans in there before going to 3:31's. Thanks for the info. 2K rpm's @80mph sounds like just what I am looking for.

 

[Corb@CorbinShipping]

Thanks Bud, I think I will go with the deal that Corb threw out there on the 3:55's. Then if I am not happy move on up to 3:31's. Maybe try to slide a BTS trans in there before going to 3:31's. Thanks for the info. 2K rpm's @80mph sounds like just what I am looking for.

Let me know when you are ready. I can meet you in Pensacola. Only an hour from me. About the same from mobile.I'll trade Dave for his front gears when he is ready upgrade! LOL

 

[AllanB]

Will do. I said 3 to 4 weeks. I will see about putting some other mods on the back burner and go ahead with this. But I will let you know. Thanks again.

 

[Corb@CorbinShipping]

Will do. I said 3 to 4 weeks. I will see about putting some other mods on the back burner and go ahead with this. But I will let you know. Thanks again.

No rush. I am gonna be out of the loop for about that long... Bike trip... AND, I gotta dig them out of the garage! LOL Get your other stuff done, and I am not going anywhere, and neither is your soon to be rear gear set.

 

[Jeremy]

Where is everyone getting the 3.31's? I put 3.55's in the 06 6.0, but wanted to try 3.31's. I got a set from ford for the 2011's but the rear diff is different in the 2011's. Pinion was larger and longer.

thanks