Gen 1 with 4 Auto (TOD)

[trick76cj5]

Stepping into the “academics” of how the TOD works, curious what triggers the clutches engagement and its “percentage”. It would seem to me that TC would be the primary trigger for engagement, but “100%” clutch engagement would make me think you would at least get some feeing of the binding on the circumstances we were mentioning before (slightly wet roads, right hand turn and stepping on it). Curious if the system acknowledges wheel speed sensors in the front and the TC associated with the front to engage up to “100%”. It makes me think that anything full dirt or snow would be better served with 4H to ensure full front axle engagement from the second you may be losing traction.

These transfer cases aren't that smart, there aren't any electronics involved in the transfer case "kicking in". This design is
using the equivalent of a limited slip unit like what is in a differential. It will transfer the power 50/50 up until the clutches slip thus allowing a torque bias. in 4auto, the shift mechanism loads the spring against the clutch a small amount thus allowing the clutches to slip at a lower torque. When shifted into 4hi, the shift mechanism increases the spring load thus increasing the clutch holding power.

The Gen 2 cases actually have a locking pawl that that engages when in 4hi/4lo. The gen 2 cases are preferred for those who intend high horsepower, rock crawling, or generally heavy offroad use as @Primez pointed out.

 

[mashtastic]

And that’s why they are hard to find in junkyards.

 

[Justbob]

That is very interesting. Part of my motivation to do this was associated with my plan to supercharge the truck and not have to get traction bars (still planning on Deavers).

 

[trick76cj5]

Ok, i was finally able to get to the installation today. I didn’t get it finished because I ran into a small snag.
1) The transfer case control module out of a 2014 F150 w/TOD worked on my truck. In stalled the new switch and was able to cycle through the 4 different settings (2wd, 4auto, 4hi, 4lo).
2) The wiring harness plug on the 2019 raptor transfer case range select motor is not the same style connector. The motor appears for all purposes to be exactly the same. I swapped the transfer case range select motor from my 2014 onto the 2019 t-case. It was a direct swap, but i did have to cut and solder the wire that goes directly into the transfer case.
3) The transfer case mounted up to the 6R80 trans just fine (you are supposed to replace the mounting bolts, they are aluminum . . . But i reused mine).
4) The front driveshaft works just fine, the distances are exactly the same.

Now for the problem, the rear slip yoke on the 2014 is different from the 2019, so I have a 2019 slip yoke on order. I will swap that out when it gets here and give the rest of my feedback.

The rear of the t-case is about 1” longer than the 2014, so I will likely shorten the rear drive shaft by 1” in the very near future, but as long as I’m not off roading it hard, it should be fine.

 

[trick76cj5]

Here are the side by side pictures of the connector.

 

[mashtastic]

What about getting a 2019 rear drive shaft that has the yoke and length?

 

[trick76cj5]

Ok, update now that I have dug into this a little further. It is unusual that I jump into a project without having all the details. Additionally, I will start a whole new post once I have all the details of the installation and what is and isn't possible.

But, i want to clear up some of the wrong information I gave a few posts earlier.

1) The wire that goes into the back of the T-case is not a speed sensor, its actually an electronic clutch solenoid. I did not know this, but all these t-cases have a lock up clutch that operates like a synchro in a manual trans that brings the driveline up to speed before the shift motor engages the 4wd fork into the 4wd location. Additionally, this is the solenoid that is used to vary the 4Auto function, but in the 4auto t-cases, it is acting upon a full clutch pack, not just a single metal/metal friction plate.

2) The 4 auto function is smarter than I originally understood, but it is controlled by the TCC Module, not the transfer case itself. That 4auto TCCM controls the Pulse Width (effectively the voltage) to the solenoid generating different pressure on the clutches. The TCCM controls the pressure based on measured slip front/rear, steering input, ABS state, and probably a few other inputs. Sorry @Justbob for oversimplifying this in my earlier response, but this is all happening within the TCCM which we have to swap for 4auto so we don't have to worry about it technically.

3) The 4 auto with High lock on the 2018 and newer raptors uses the same clutch for 4auto function, but also uses the shift fork and mechanical engagement that is found in the standard 4wd t-cases. Unfortunately, per AllData, the 2014 TCCM does not move the shift motor in either 4A or 4Hi positions. So, this is where I think i've run into my first major hurdle.

So at this point, it appears it will all work, once my drive shaft arrives, but I will not have the lock feature i was planning.

I have ordered a TCCM out of a 2018 in hopes it will play well with the rest of the systems on the older truck and give me the lock feature i wanted.

This is not a how to, or a recommendation. Once i get this part in (late Feb. ETA) i will try it out and then report back. I will also make a stand alone post with all the technical specifications for the different transfer cases since this information appears impossible to find anywhere on the web currently.