2010 6.4L with 3.55's ?'s

[k.thed]

Afte an exhaustive search, I think I've finally found my next truck..... possibly. I'm come acrosss a 2010 F350 CCLB SRW 4wd with 3.55's in it. I've driven alot of 6.4's with 3.73's, and I drove a company truck for about a year that was a 2011 6.7L with 3.55's. The 6.7L was a beast. It didn't matter what I put behind it, it drug it all day long, and got good mileage to boot. I'm assuming the 6.4's are about the same, but with the 5 speed auto instead of the 6, I didn't know if I should expect alot of difference.

Does anyone have a 6.4/3.55 combo that would like to give me some insight? I've searched through thread after thread that had some mileage data, but no real discussion. I'd appreciate it if someone could chime in and give me their .02 about a 6.4/3.55.

[travisH3]

My window sticker says 3.55 gears but I don't see how because mine runs about 1900 rpms at 65-70. I need to find out another way to double check. I think I should have 3.73's

[Evil PSD]

TravisH3 check the tag on your front and rear axle. I have 3.55 as well I dont have a problem with them, but I dont tow really but it seems like it would pull anything haha

[k.thed]

They didn't introduce the 3.55's in the 6.4's until 2010 did they?

[jaeger]

Yaa great combo. I also have 355s under my 6.4 and I love it. I have never really figured out my fuel mileage but I know its a lot better with my Mini Max and S&B cold air intake

[Doss]

Yeah, I wanted 3.55s in mine. Got 3.73s because it wasn't a deal-breaker to me.

In fact, I think I could handle a 3.08 really. I don't haul super heavy loads and the truck makes way more torque than I really need. I can see it being a problem running a gear like that if you normally haul 15000+ lbs though.

My friend pulled his 17,000 lbs boat with his '10 with 3.55s and never had an issue if that helps any.

[BIG Laing]

Originally Posted by k.thed

Afte an exhaustive search, I think I've finally found my next truck..... possibly. I'm come acrosss a 2010 F350 CCLB SRW 4wd with 3.55's in it. I've driven alot of 6.4's with 3.73's, and I drove a company truck for about a year that was a 2011 6.7L with 3.55's. The 6.7L was a beast. It didn't matter what I put behind it, it drug it all day long, and got good mileage to boot. I'm assuming the 6.4's are about the same, but with the 5 speed auto instead of the 6, I didn't know if I should expect alot of difference.

Does anyone have a 6.4/3.55 combo that would like to give me some insight? I've searched through thread after thread that had some mileage data, but no real discussion. I'd appreciate it if someone could chime in and give me their .02 about a 6.4/3.55.

With the gearing change with the 6 speed in the 6.7 vs the 5 speed in the 6.4

6.7 3.31 is close to 6.4 3.55
6.7 3.55 is close to 6.4 3.73
6.7 3.73 is close to 6.4 4.10

Pissing Match. this thread got severly off topic, but post #31 is what you want to look at.

[BIG Laing]

Originally Posted by Doss

Yeah, I wanted 3.55s in mine. Got 3.73s because it wasn't a deal-breaker to me.

In fact, I think I could handle a 3.08 really. I don't haul super heavy loads and the truck makes way more torque than I really need. I can see it being a problem running a gear like that if you normally haul 15000+ lbs though.

My friend pulled his 17,000 lbs boat with his '10 with 3.55s and never had an issue if that helps any.

I can't find the video, but there is a f350 on YouTube breaking some sort of landspeed record. The only thing they modified is safety stuff, lowered the truck, and changed the gearing in the rear diff. I wanna say they put between 2.25 and 2.50 gears in it. The. They hit 185+ mph!

[BIG Laing]

Originally Posted by BIG Laing

I can't find the video, but there is a f350 on YouTube breaking some sort of landspeed record. The only thing they modified is safety stuff, lowered the truck, and changed the gearing in the rear diff. I wanna say they put between 2.25 and 2.50 gears in it. The. They hit 185+ mph!

I found the video, and it is not how I remember it. Heavily modified, and I can't find where it says what reared they have.

Ford F-250 Land Speed Record - YouTube

Ford F-250 Land Speed Record - YouTube

[montana6.0]

I've got that that exact set up with 35s. And have pulled 35' fiver, 24' enclosed snowmobile trailer, oh and flatbed trailer with skidsteer. and it will pull all just fine just takes a bit to get er moving. And have pulled over all these mountain passes here in Montana, it did just fine. Do 70-75 pretty easy with everything. Fuel mileage was always right around 10.5 to 11.5 it seemed like. That's with the mini, 4" exhaust, and cai. That's my experience hope it helps.

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