Transfer Case Technical Discussion

[Ducati1098]

Were they towing in 4A? because (I do not know and I am asking you the expert) I would think the clutches should not have been engaged at all if they were in 2H.... There fore they should not have been smoked right?

From what I remember, yes. They normally used 4A, didn’t correctly put it into neutral tow mode, and then towed it.
To be honest I don’t remember all the specifics. There was another video he posted before that one I believe, but long story short, all the damaged was caused after flat towing it.

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[5GENIDN]

From what I remember, yes. They normally used 4A, didn’t correctly put it into neutral tow mode, and then towed it.
To be honest I don’t remember all the specifics. There was another video he posted before that one I believe, but long story short, all the damaged was caused after flat towing it.

My misunderstanding... I thought you meant they were towing with the Bronco not towing the Bronco.... That is pretty significant. But the clutches had to be engaging to smoke them like that.... And if everything was off I would think the sensors might not have picked up on an overheat... I do not know... I am just trying to think through all of this.... Random thoughts with no experience behind it....

 

[CalvinT]

I've been following this for a while, mainly out of curiosity. I don't intend to do any extreme off road or rock crawling. This talk about clutches has me wondering. Do the clutches in the 4A transfer case slip when the transfer case is in 4H or 4L? It's my impression there isn't suppose to be any slip in those modes. If there is, then the clutches are underrated?

Just being curious.

 

[SierraBronco]

I've been following this for a while, mainly out of curiosity. I don't intend to do any extreme off road or rock crawling. This talk about clutches has me wondering. Do the clutches in the 4A transfer case slip when the transfer case is in 4H or 4L? It's my impression there isn't suppose to be any slip in those modes. If there is, then the clutches are underrated?

Just being curious.

The last couple days have been focused almost purely on this possibility as there is no physical lock used for 4H or 4L, only fully engaging the clutch.

I apologize for not jacking the thread to a different topic that would keep the modern mind to continue reading within the thread rather than losing focus after 16.9 seconds due to the way we have now been conditioned to receive information. I will strive to do better.

 

[Brian_B]

Doesn't every SAS model comes with the 4A?

I get a mechanical lock is going to be stronger, but I don't recall seeing tons and tons of SAS models being crippled by this either. Really, the flat tow issue is the only thing I can really recall being endemic (maybe?) to the 4A Tcase.

Will be interesting to see what the Braptor/Ranger Raptor (Rrrrrraptor?) Tcases reveal.

 

[SierraBronco]

Doesn't every SAS model comes with the 4A?

I get a mechanical lock is going to be stronger, but I don't recall seeing tons and tons of SAS models being crippled by this either. Really, the flat tow issue is the only thing I can really recall being endemic to the 4A Tcase.

Will be interesting to see what the Braptor/Ranger Raptor (Rrrrrraptor?) Tcases reveal.

Correct-every SAS has 4A. I’m not sure how many others are having this issue either and again-we don’t even know if this is the problem. Just that dealer can’t find any problems with wiring or modules. But we do wheel ours pretty damn hard. And it’s heavy. Then heavy 40’s. Plus full belly skids so-hot up in there. It was a problem on F150’s to the point Ford gave the Raptor a lock and maybe the braptor so…maybe?

 

[Snacktime]

Went a looking, apparently there is a shift solenoid on the back of the case for lock up.

https://www.fordraptorforum.com/threads/anyone-want-to-see-the-inside-of-their-transfer-case.84702/

@Brian_B only a few of us here have lower trim Broncos with the Holy Grail transfer case lol.

 

[SierraBronco]

Went a looking, apparently there is a shift solenoid on the back of the case for lock up.

https://www.fordraptorforum.com/threads/anyone-want-to-see-the-inside-of-their-transfer-case.84702/

@Brian_B only a few of us here have lower trim Broncos with the Holy Grail transfer case lol.

Need to see what the Braptor (allegedly) uses for lockup. I haven’t been able to find any breakdowns on that tcase yet.

 

[BigMeatsBronco]

The modern equivalent of disengaging the hubs is disengaging the hubs. F-150s have had vacuum hubs for decades and the latest generation swapped to electric actuation, but they still disconnect the hubs when 4x4 is off. As has been mentioned, these frequently cause issues, but when they're working they're nice.



Link? The Raptor has dual engagement - clutch pack for 4A operation plus a locking ring for locked 4H operation. This is unique to the Raptor TC.

The 4A F-150 transfer cases all have a clutch pack only, which can overheat with extensive use and can slip if its torque rating is exceeded. The non-4A transfer cases just have a locking ring so there's never any slip.

The info in this thread on the Bronco's 4A case made no mention of dual engagement style like the Raptor:

look at the diagrams, it's obvious the Broncos AWD also has the locking ring.

There's also a newer version of the F-150 that comes with torque on demand and does not have inner axle disconnects

 

[SierraBronco]

look at the diagrams, it's obvious the Broncos AWD also has the locking ring.

There's also a newer version of the F-150 that comes with torque on demand and does not have inner axle disconnects

Could you share the diagrams you’re referring to? Watching the video @Snacktime shared earlier I’m not understanding how there is a lock on the 4A tcases. (There’s a lot of fluff watching him struggle with clutch plates. 4:46 and 15:58 are notable timestamps)



Advanced Tcase

Non 4A tcase with locking mechanism:

 

[BigMeatsBronco]

Just swap it all out with a 10r80 and rappy tcase. Call it a day.

this will create Driveline issuse for us 2dr folks, Iva already tried that.

 

[SierraBronco]

this will create Driveline issuse for us 2dr folks, Iva already tried that.

Lmao. Of course you have

and dammit.

updated last reply with pictures

 

[BigMeatsBronco]

This is the video where I had the “ah ha!” moment realizing there was no mechanical lockup! Actually sent it to @5GENIDN this morning with the timestamps to look at to show it.

When I replace the clutch I’m going to leave the Tcase installed. Doesn’t look like it should be too much of a hassle especially with the extra clearance of the body lift. But I’m certainly not opposed to pumping as much fluid in as possible until it seems the fill rate doesn’t match the spill rate then throwing the plug on as quickly as I can…

Your missing rhe part where the internal splines on the shaft actually do travel far enough to engage, makeing a mechanical connection. I'm driving mine with no front drive line right now and when I spin the rear tires in all-wheel drive the code comes on the dash and says " temporarily locked 4x4"...this happens when the motor pushes PAST the awd clutches mode, and engages the inner splines past the clutch pack.

 

[BigMeatsBronco]

I have a RR and SAS bronco, I see no visual difference on the Tcase, ( except for driveshaft flange)I also assume the Braptors use the exact same tcase.

 

[BigMeatsBronco]

here's where the lock up occurs....on the splines themselves

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