4.46 vs 4.7 Gear Ratio Discussion

[Paul Gagnon]

Mechanical speak yes

Customer speak no

There is only one way to say it correctly.

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[Sixtysixpride]

There is only one way to say it correctly.

Well apparently there is not or I wouldn’t have stated it the way it’s described among the non-mechanically inclined side of our development teams most of whom actually sign the checks for the rest of us. I get what you’re implying however there’s also descriptors in languages that aren’t married to the technicalities of the preceding word. So actually both are still right in the end.

Congratulations you’re half right and still wrong.

 

[GToddC5]

Fuck. Even when we have facts, we argue over them. Can't even make this shit up.

 

[Hossfire]

I think that If you are going to run larger tires, buying into the higher gear ratio makes sense. The advanced 4WD and front/rear lockers makes sense. You can do that on OBX and BB without going SAS. BL BL is almost SAS factory.

The real question at this point is whether you can get SAS or not this year. If getting SAS looks doubtful, get the gearing and 4wd options and then have the suspension, wheels, tires done aftermarket. Talk to several shops and get recommendations.

My chances for my Wildtrak look reasonably good at this point. If the odds shift out of my favor, the Non-Sas BL looks really good and saves me some money. I can put some miles on the 33 KO2s and decide whether I really want the 35s.

 

[RainbowStix]

so 37s on 4.46 2.3L is not ok?

 

[indio22]

so 37s on 4.46 2.3L is not ok?

Reality use jumped the shark the minute that damn reservation list appeared, lol. These days it's about "how my Bronco makes me feel". Hence Sas and 37s for that epic "rock crawl" to Costco.

 

[Hot cheetos]

so 37s on 4.46 2.3L is not ok?

Probably still twice as fast as my ranger on 33s

 

[rguest3]

I think the computer on my truck likes the 37s better than the Sasquatch "35s" it came with. At least the Speedometer does. The speedo it dead on accurate with the 37s. No need to recalibrate.

 

[GToddC5]

I think the computer on my truck likes the 37s better than the Sasquatch "35s" it came with. At least the Speedometer does. The speedo it dead on accurate with the 37s. No need to recalibrate.

I feel the same with my stock Badlands. The speedo is off with 33s, and will probably be perfect when I choose a 35 setup.

 

[Macclone]

My OB has the 3.73 rear axle. Any issue going to 35s and 2“ lift?

 

[dgorsett]

All this boils down to 5%, so probably makes no difference. Got me to thinking: I've had off roaders with gear ratios from 3.23 to 5.38. 3.23 was a POS off road and 5.38 was a POS on road (neither due soley to gear ratios but long story), but everything else from 3.50 to 4.27 has been fine.

 

[Zimm]

I just ran into this thread looking at various gear ratios and packages. I read the first few pages and the last, and I think the OP and the the rest of the conversation misses the actual point of the ratio choices when its continually repeated there's only a 5% loss of applied tq. Yes that true, and on its own that's all that would really matter, IF we were using electric motors with 100% tq available at 0 rpm and being basically unstallable.

As it stands though, theses are internal combustion, and turbos to boot, so they are going to be RPM sensitive. As such Ford is doing 2 things with the ratios, 1) maintaining fuel economy so as to be in compliance as a corporate entity, 2) keeping the engine from stalling when used to crawl in the mid 100's of rpm, when you're not really yet in the power band.

This matters much less with an automatic as the tq converter generally gives a 2:1 multiplication and is unstallable, but you really don't want to rely solely on that as you could burn up the autobox, so lets say it's an effective 100% usable 1.5:1.

When I was wheeling a lexus lx470 on 35's, I didn't bother to change the diff ratios. It wheeled fine but was really sluggish on long highway grades. The current fj60 I use is a manual and has 4.88 rears, with a 2.3 case and a 4.7 case. At about 250:1 its 2f naturally aspirated tractor motor I adapted to FI also is unstallable, as idle speed in low low low is about as fast as an old man in Hospice shuffling with a cane. I do prefer it though, as brakes aren't needed to stop on a technical steep climb. I just shut it off in gear, and restart it when I need. The starter motor does all the work.

So as you see, yea its true there's only a 5% loss and no it doesn't matter a whole bunch when all you do is the street driving 99% of these trucks do. The observation itself tends to lead to arguing though, because it's all much ado about nothing, when it has nothing to do with why the ratios are utilized in the first place.

 

[indio22]

I just ran into this thread looking at various gear ratios and packages. I read the first few pages and the last, and I think the OP and the the rest of the conversation misses the actual point of the ratio choices when its continually repeated there's only a 5% loss of applied tq. Yes that true, and on its own that's all that would really matter, IF we were using electric motors with 100% tq available at 0 rpm and being basically unstallable.

As it stands though, theses are internal combustion, and turbos to boot, so they are going to be RPM sensitive. As such Ford is doing 2 things with the ratios, 1) maintaining fuel economy so as to be in compliance as a corporate entity, 2) keeping the engine from stalling when used to crawl in the mid 100's of rpm, when you're not really yet in the power band.

This matters much less with an automatic as the tq converter generally gives a 2:1 multiplication and is unstallable, but you really don't want to rely solely on that as you could burn up the autobox, so lets say it's an effective 100% usable 1.5:1.

When I was wheeling a lexus lx470 on 35's, I didn't bother to change the diff ratios. It wheeled fine but was really sluggish on long highway grades. The current fj60 I use is a manual and has 4.88 rears, with a 2.3 case and a 4.7 case. At about 250:1 its 2f naturally aspirated tractor motor I adapted to FI also is unstallable, as idle speed in low low low is about as fast as an old man in Hospice shuffling with a cane. I do prefer it though, as brakes aren't needed to stop on a technical steep climb. I just shut it off in gear, and restart it when I need. The starter motor does all the work.

So as you see, yea its true there's only a 5% loss and no it doesn't matter a whole bunch when all you do is the street driving 99% of these trucks do. The observation itself tends to lead to arguing though, because it's all much ado about nothing, when it has nothing to do with why the ratios are utilized in the first place.

I don't have the calc in front of me, but the engine rpm difference between 4.46 and 4.7 differential gears is relatively small, something like 150rpm.

My manual base Bronco with 4.46 diffs was actually a bit steep on pavement for the stock 30" tires. After swapping to 35" tires the vehicle operates better, although top gear 6th is less useful.

The low speed crawl ratio even with 35s is still better than my old Jeeps, and I wheeled those all over without much issue. So I think there is some leeway in terms of gearing and tires, and I'm happy Ford went steep on the base manual with the 4.46.

I would not bother switching to 4.7, there is not enough value for the small difference in my view. I would consider going to 5.xx depending on vehicle usage, although I'd want to avoid a too steep first gear on pavement.

 

[Zimm]

With a tq converter there's no point, with a stick, I'd opt for the 4.7 factory given all else equal, but it wouldn't be on the "to do" list to pay the money swapping later.

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