100% correct with that assumption. My 4.30 trucks run down the hwy at 2,000 rpm / 70 mph towing 10,000+ lbs with no drama or upshift downshift games. Short tire or 2wd trucks go 3.73 & taller tire trucks go 4.30 IMO.

 

Good debate. I'm hearing multiple sides of the equation.

Our little 330 with a 6 speed auto. can't be locked into a specific gear that provides the desired RPM range. The option just under Drive is too low to be practical for the open road. But, if the newer units can be manually locked into a gear that allows for the engine to be pulling in it's sweet spot without undo heat being generated into the trans. fluid and with no ill side effects to the transmission then I'm 100% for doing that. Regearing is basically doing the same thing, unless my thinking is off base.

For those who own the newer 10 speed auto's can the trans be held in a specific gear without allowing it to upshift into a higher gear so as the engine RPM be kept in a desirable RPM range for the load being towed? Our older 6 speed can't but I wish it could.

 

Can be held in gear by locking out high gears .i.e. lock out 9th and 10th and the truck will use 1st-8th. Also, ford has manual mode where you control the upshifts and down shifts. So let's say your towing 10k through rolling hills and your truck keeps shifting between 6-10th if you wanted to you could shift it into 8th in manual mode and leave it and the truck won't upshift or down shift without you allowing it to. It's a really cool feature for towing imo.

 

Is 8th the only gear that the transmission can be held in or can any gear be limited as the highest it will shift to?

 

Maybe Ford did and thats why there is no more 3.55 in the Super Duty but the tried and true 3.73 that's been in these Super Duties forever still stands up to the sands of time pulling loads without stepping up to the big boy 4.30 gears.

Leave the 3.55 in the 1/2 ton and the prius.

 

You can manually shift all the way from 1st-10th with a +/- button on the gear selector. The computer will prevent you from upshifting or downshifting too fast. If you aren't turning enough RPM it won't let you upshift, if you're turning too high RPM it won't let you downshift.

I had a DRW with 3.73s and it could shift into 10th gear around 45mph the very soonest and a DRW with 4.30s I can shift into 10th gear at 36mph. At 40mph in 10th gear I drove for almost 40 miles and I was getting 30mpg at about 16-1700rpm. My truck with 4.30s will skip shift at 6mph from 1st to 3rd. That is the problem speed around parking lots where you hit 5pm then go to hit the brakes and before your foot hits the pedal it skip shifts and you slightly pick up momentum from the coasting in the higher gear. If you dont have 31.5" tires with 4.30 gears it is probably a higher speed where it will skip shift.

 

From the manual for manual shifting.

 

The function options of the 10spd are full automatic, automatic mode using gear lockout, or manual mode.

Full automatic is you put the selector in D and the computer does everything.

Automatic using gear lockout is you put the selector in D and then lock out the higher gears you dont want the transmission to use. The computer still does all the work but will only use the gear range you allow. An example, you are driving down a 25mph road with slight hills and the transmission is shifting up and down constantly so you lock out 10th, 9th, 8th, 7th, 6th, and 5th, only allowing the computer to use 1-4 automatically.

Manual mode is just that. Of course the computer isnt going to let you be wreckless and does limit you from changing into certain gears at certain speeds/rpms but the gear you manually select is the only gear the transmission uses.

Personally when towing I use the lockout feature the most while leaving the transmission in D. Just yesterday I was in my F250/6spd with the same transmission functions as the 10spd. I had roughly 11k in tow and was cruising 60mph in 6th gear. For the hill ahead I lock out 6th and 5th leaving the transmission only 1-4 to utilize. 4th gear was plenty to pull the hill at half throttle around 2500rpm and I had no worries of the transmission possibly shifting up to 5th before I crest the hill. Once at the top I add back 5th and 6th and the transmission shifts back up to 6th gear.

I will suggest you go test drive an F250/F350 2011-2022 and witness the functionality of the transmission for yourself. F250/F350 Transmissions from 2011 forward have the lockout and manual modes all the same.

 

The idea that the 3.55 gear doesn't work is silly. The interweb has the proof. There was a guy early on who loaded his back hoe up and towed 24,000 lbs up a mountain in a truck with a 7.3 and 3.55 gears. That is 10,000lbs over what it is rated to tow and yet nobody died....
My truck has the 3.73's and bigger 35" tall tires. Doesn't bother it to tow a little over either, even at high altitude. The notion that the taller geared trucks are somehow not as good is hilarious... If you are going to frequently tow over about 12k lbs, I would opt for the 4,30's. At the end of the day the biggest penalty for doing so might be 1 mpg when empty. My truck is empty or lightly loaded more than anything. The 3.73's work.

 

From my own personal experience of 11 months and 5300 miles of use in northwestern Wyoming and Montana. The 3.55’s 33.2” tires are great for higher mpg cruising at higher speeds in the lower elevations on flat land empty.

The 3.55’s are not so good at low speeds, towing, off pavement, mountain driving, accelerating quickly, bigger heavier tires. 3.55 truck will not tow in 9th and 10th.

My identical 4.30 34.5” M/T tire truck now after 9 months and 4700 miles does everything well even with the bigger heavier tires just gets slightly lower MPG empty. I believe it gets the same or better mpg as the 3.55 truck towing because it’s able to easily tow in all 10 gears. The 4.30 truck just drives better especially towing.

I just try to cruise at 65 mph max with the 4.30’s empty or towing to get better mpg.

 

I realize we're talking apples to oranges in reference to your truck to mine but I found what you're saying to be true when I regeared our little 330 V-8 to 4.30's. It does everything easier in comparison to the 3.73.

 

With the advent of 10 ratios in the trans now you need to consider overall gearing and not how it used to work when 4-6 speed transmissions were used. I believe the 10 speed 3.73 truck has a lower overall first gear ratio than the previous 4,.30 rear and six speed auto combination. First is really low even on a 3.73 truck, so low it almost always tries to skip to third. With 16k behind the truck I can feel it struggle a little in first and second gears. This is where the 4,30's shine. Once rolling it is pretty much a wash because the ten speed makes up for the tall gears in the low numerical ratio trucks and the deep gears with the triple overdrive ratios.

 

I've followed the 7.3/10spd combo fairly closely as I was planning on ordering one last August......I ended up with a diesel but I have no doubt that the 7.3 has proven to be a solid engine offering great performance for a gas engine. As far as the 10spds go, I think there were a few more problems initially but they've been pretty solid since. I love the 10spd and won't be going back to a 6spd ever.......HUGE difference in towing IME.

As far as the gears go, I think the 3.55's are a bit tall for a 7.3/10spd and the 4.30's are a bit low for a 6.7/10spd but the tranny's gearing works well to minimize both issues.

We ordered a 2023 7.3/10spd 3.73 last week to add to the fleet.

Dave

 

If I were ordering fleet SD work trucks. I would definitely order them with the new standard no additional cost 6.8 and with the standard no additional cost open differential 3.73. Ford specifically designed it for that use.

But for my personal truck I would definitely choose the 7.3 with 4.30’s.

 

It's a small fleet; I'm sure the 6.8 (though unproven) will be a fine powerplant since it shares most of it's parts and design with the 7.3 but the 7.3 is, well, better.....but the biggest thing is the "lighter duty" 10spd - for the small premium for the 7.3 you get the 10R140 which, while not perfect, has proven to be pretty reliable I think.....maybe the "baby SD 10spd" will be the greatest tranny Ford has ever built....or not.

Dave