Question about Transfer Cases with Crawl Gear

[Little Foot]

So I ordered a Black Diamond, 7 Speed Manual, Non-SAS with the standard transfer case, not realizing that there is a gearing difference between that one and the Advanced transfer case. Quite honestly I didn’t think about it because my previous build had SAS, 2.7L, etc….

How much of a difference will this make as I put on 35s or 37s and later down the line as I take it out to play on the rocks?

I don’t care about the 4A option in the capabilities of the transfer case for this discussion.

I’ve been told that my build has been picked up, but we do not have a VIN yet. Build for the week on 25 April. Probably too late to ask for Advanced Transfer Case to be added?

Thank you in advance for replies as I obviously don’t know and relying on others that do know.

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[Little Foot]

Any input would be great

 

[BigMeatsBronco]

So I ordered a Black Diamond, 7 Speed Manual, Non-SAS with the standard transfer case, not realizing that there is a gearing difference between that one and the Advanced transfer case. Quite honestly I didn’t think about it because my previous build had SAS, 2.7L, etc….

How much of a difference will this make as I put on 35s or 37s and later down the line as I take it out to play on the rocks?

I don’t care about the 4A option in the capabilities of the transfer case for this discussion.

I’ve been told that my build has been picked up, but we do not have a VIN yet. Build for the week on 25 April. Probably too late to ask for Advanced Transfer Case to be added?

Thank you in advance for replies as I obviously don’t know and relying on others that do know.

This post is a bit confusing...

The crawler gear is the lowest and its in the transmission not the transfer case. The two different transfer cases do have different ratios with the advance Trac having the lower gearset. Additionally there are gearing choices in the axles themselves...

What gears are you curious about, the transfer case ratios?

 

[BOLD Renegade93]

Maybe I’m just missing it, but the Advanced 4x4 doesn’t automatically give you the 4.7 gears. I couldn’t find it anywhere in the ordering guide or B&P. If you throw SAS on there with the Advanced transfer case, then you get the 4.7 gears.

My 2021 Black Diamond non-SAS with the Advanced 4x4 and 7MT has 4.46 gears

 

[Drex]

From memory; you lose 2.72/3.06 of gearing advantage in 4L (about 13%) with the regular transfer case. I would expect the computers torque limit the bejesus out of the engine in C, so you probably won't notice a difference as a practical matter. Obviously 4H and 2H are the same.

 

[Mdsuits]

I believe the basic case is the standard 2.72 and the advanced is 3.0 so not a huge difference……I really wish ford would have done done a 4-1 in the badlands cause with the auto the gearing is pretty meh for technical crawling. As long as you don’t have a vin you can change it.

 

[jjack50]

The advanced transfer case has a lower low gear ratio than the regular transfer case. The net effect is that with the crawler gear+low gear you get a 95:1 crawl ratio with the advanced and a 85:1 crawl ratio with the standard. It’s not a difference worth worrying about in my opinion.

 

[Bmadda]

IIRC lowest possible total crawl ratio on any stock Bronco is 95:1. Only achieved w/7mt/4A/4,70 combo on mansquatch/badlands. Wana know what yours is gonna be? Do the math...trans ratio*xfer case ratio*final drive. If you figure out the "rollout" for a given tire size you can calculate ram/speed. What does that mean on the trail? Squat till you actually try using it! I doubt you will notice a huge difference TBH.

 

[Techun]

The advanced transfer case has a lower low gear ratio than the regular transfer case. The net effect is that with the crawler gear+low gear you get a 95:1 crawl ratio with the advanced and a 85:1 crawl ratio with the standard. It’s not a difference worth worrying about in my opinion.

With a BD his crawl ratio is slightly worse, but the statement still stands

 

[BOLD Renegade93]

I haven’t had enough coffee today yet so bear with me here…the Advanced transfer case by itself does not have a lower low gear ratio than the standard one right? Both should have 4.46 in this configuration. The 4.7 doesn’t happen unless you add SAS. So in this context, the OP needs to decide if he wants to add the cost of SAS to his build, not just if he wants 4.7 gears

 

[jjack50]

Maybe I’m just missing it, but the Advanced 4x4 doesn’t automatically give you the 4.7 gears. I couldn’t find it anywhere in the ordering guide or B&P. If you throw SAS on there with the Advanced transfer case, then you get the 4.7 gears.

My 2021 Black Diamond non-SAS with the Advanced 4x4 and 7MT has 4.46 gears

It’s not the final drive ratio that OP is talking about but the difference in the transfer case low gearing. Final output is based on three gear ratios; transmission, transfer case, and final drive.

 

[BaseBD]

The difference in ratio is about 10% between the two. So there will be some impact. Not sure how noticeable it will be as I dont do much Rock crawling. Back of the napkin difference is 88:1 crawl for the advanced vs 80:1 with the standard assume you have a black diamond with the 4.46 rear end. With the 80:1 you are going ~.78 mph in crawl @600rpm with a 35 and .82 mph at crawl with 37. At 88:1 with the advanced it's ~.71 mph with 35s and .74 mph with 37s. You are going pretty slow with all of them.

 

[BOLD Renegade93]

It’s not the final drive ratio that OP is talking about but the difference in the transfer case low gearing. Final output is based on three gear ratios; transmission, transfer case, and final drive.

Ok that’s what I figured. I was interpreting his question in the wrong context. Thought I was smoking something. Thanks

 

[Little Foot]

Maybe I’m just missing it, but the Advanced 4x4 doesn’t automatically give you the 4.7 gears. I couldn’t find it anywhere in the ordering guide or B&P. If you throw SAS on there with the Advanced transfer case, then you get the 4.7 gears.

My 2021 Black Diamond non-SAS with the Advanced 4x4 and 7MT has 4.46 gears

Right......The axle is running 4.46 gears, but my understanding is that the transfer case is geared much higher (deeper) with the Advanced 4x4 Transfer Case versus the Standard Transfer Case.

I think the standard transfer case is geared at:
High: ???
Low: 2.72:1
Crawl Ratio: 79.92:1

Versus the Advanced 4x4 Transfer Case:
High: ???
Low: 3.06:1
Crawl Ratio: 94.75:1

When in High Range, are both Transfer cases geared the same?

The below thread has the transfer case breakdown of 4 Low

https://www.bronco6g.com/forum/threads/low-range-ratio-of-transfer-case.12339/

 

[jjack50]

I haven’t had enough coffee today yet so bear with me here…the Advanced transfer case by itself does not have a lower low gear ratio than the standard one right? Both should have 4.46 in this configuration. The 4.7 doesn’t happen unless you add SAS. So in this context, the OP needs to decide if he wants to add the cost of SAS to his build, not just if he wants 4.7 gears

The advanced case does have a lower low gear ration than the standard case.

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