STUCK IN 4L - Dealer "can't" Solve - TCCM/transfer case issue???

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Drumguy999

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Ok, I haven't spent much time on forums in recent years, so I'll try to keep this post concise. 2018 model year, 59k miles. I'll first describe what it's currently doing then the back story below it for those interested:

The dealer states that there are 2 wires in the TCCM harness that are not communicating properly, and the whole dash must come out to properly diag it. (i have little faith in their abilities currently, but I'm not excluding it)

Switching from 2H to 4A. From what I can tell, this seems to work just fine every time without issue, and the truck responds correctly
Switching from 2H to 4H. INTERMITTENTLY works. sometimes it shifts into 4H just fine, sometimes it gives me a powertrain fault and defaults back to 2H.
Switching from 2H to 4L. Same issue as 4H. The other night it wouldn't shift into Low but after several attempts it finally went into 4L. Unfortunately it was STUCK there for some time. I had to drive 20+ miles home and after about 40 attempts to get it OUT of 4L it finally did.

**it should be noted that every time i select a drive mode on the 4wd switch, i can actually feel and hear the tcase shift motor trying to select the proper drive. but often it will then default back to 2H, and give me a warning**

Is it more likely to be the TCCM or the wiring itself? I am unsure exactly how the wiring can be messed up, but i have not yet looked at the harness myself.

From my browsing, it seems that @FordTechOne has pretty extensive knowledge of the 4wd systems and logic maps, so I am hoping he can chime in.



Incident:
Traveling on the highway approx 65mph. I had the truck in 4A as it was wet/icy out. Everything was going along fine, and then i hit a bridge transition with ice on the other side. I felt the front end lose grip, and then felt the 4wd freak out. the best way that I can describe it was like when you hit ice and your ABS module goes crazy. But when i hit the brakes to slow down, it was not the ABS making the noise/shuddering. This was shortly followed by a smell of something burning. It SEEMED like it came from under the drivers seat and I assumed it was the clutches inside the T-Case giving up life.

From that point on, if i tried to engage 4wd (high or low), it would give me a powertrain fault, and not engage. HOWEVER, if I locked the rear diff, it would somehow force it into 4H???


Take it to the dealer (under warranty)

They diag it. Say oh, its just the tcase shifter motor. Well that doesn't fix it. Still getting powertrain fualt.

They then say the housing & shift fork is bent. they replace the housing, the shift fork, shift lever from the motor, AND the clutch pack after my asking them to. I physically saw the old clutch and there was no heat markings or evidence of burning ok weird...

New shift motor, forks, clutch, casing. physically it shifts just fine by hand. however, its still throwing the powertrain warning, and not shifting via the dash switch. They are doing all this stuff on the harness, stating that 2 of the wires are 'broken' and must have been damaged behind the dash.

A day later, they come back... tell me the wiring is ok, it must be the tccm. They then put in a new tccm with no change, still getting the warning, but stating to me that it 'sometimes' works.

Im then told it IS actually the wiring and they need to pull the dash out to investigate, but this isn't covered under warranty. At this point theyve had my truck over a month, spent days trying to look at diagrams and pin outs, and I tell them to give it back because Im done dealing with them at this point.
 

thatJeepguy

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This is exactly why I’ll always prefer a physical linkage to the tcase and none of this electronic nonsense that chevy and ford uses…

If I had one thing to be critical of my gen 2 it would be only this. As I feel that its just one more failure point that doesn't need to be.

How long have you owned the truck? How long has this issue given you trouble?
 
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Drumguy999

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Ive had the truck 2.5 years. It only started after it 'freaked out' going over the bridge. Prior, there was never an issue.

but yes ive cursed it several times and said, see this is why my 4wd LEVER in my jeep is nice haha
 

GordoJay

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Ok, I haven't spent much time on forums in recent years, so I'll try to keep this post concise. 2018 model year, 59k miles. I'll first describe what it's currently doing then the back story below it for those interested:

The dealer states that there are 2 wires in the TCCM harness that are not communicating properly, and the whole dash must come out to properly diag it. (i have little faith in their abilities currently, but I'm not excluding it)

Switching from 2H to 4A. From what I can tell, this seems to work just fine every time without issue, and the truck responds correctly
Switching from 2H to 4H. INTERMITTENTLY works. sometimes it shifts into 4H just fine, sometimes it gives me a powertrain fault and defaults back to 2H.
Switching from 2H to 4L. Same issue as 4H. The other night it wouldn't shift into Low but after several attempts it finally went into 4L. Unfortunately it was STUCK there for some time. I had to drive 20+ miles home and after about 40 attempts to get it OUT of 4L it finally did.

**it should be noted that every time i select a drive mode on the 4wd switch, i can actually feel and hear the tcase shift motor trying to select the proper drive. but often it will then default back to 2H, and give me a warning**

Is it more likely to be the TCCM or the wiring itself? I am unsure exactly how the wiring can be messed up, but i have not yet looked at the harness myself.

From my browsing, it seems that @FordTechOne has pretty extensive knowledge of the 4wd systems and logic maps, so I am hoping he can chime in.



Incident:
Traveling on the highway approx 65mph. I had the truck in 4A as it was wet/icy out. Everything was going along fine, and then i hit a bridge transition with ice on the other side. I felt the front end lose grip, and then felt the 4wd freak out. the best way that I can describe it was like when you hit ice and your ABS module goes crazy. But when i hit the brakes to slow down, it was not the ABS making the noise/shuddering. This was shortly followed by a smell of something burning. It SEEMED like it came from under the drivers seat and I assumed it was the clutches inside the T-Case giving up life.

From that point on, if i tried to engage 4wd (high or low), it would give me a powertrain fault, and not engage. HOWEVER, if I locked the rear diff, it would somehow force it into 4H???


Take it to the dealer (under warranty)

They diag it. Say oh, its just the tcase shifter motor. Well that doesn't fix it. Still getting powertrain fualt.

They then say the housing & shift fork is bent. they replace the housing, the shift fork, shift lever from the motor, AND the clutch pack after my asking them to. I physically saw the old clutch and there was no heat markings or evidence of burning ok weird...

New shift motor, forks, clutch, casing. physically it shifts just fine by hand. however, its still throwing the powertrain warning, and not shifting via the dash switch. They are doing all this stuff on the harness, stating that 2 of the wires are 'broken' and must have been damaged behind the dash.

A day later, they come back... tell me the wiring is ok, it must be the tccm. They then put in a new tccm with no change, still getting the warning, but stating to me that it 'sometimes' works.

Im then told it IS actually the wiring and they need to pull the dash out to investigate, but this isn't covered under warranty. At this point theyve had my truck over a month, spent days trying to look at diagrams and pin outs, and I tell them to give it back because Im done dealing with them at this point.

A tech from the shotgun school ....
 
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Drumguy999

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A tech from the shotgun school ....
Well when I went in, he had me talking to the tech working on my truck and he was a guy in his late 50s or so, and seemed like a long time tech who knew what he was doing. so it was either a show, or he really was stumped by this.
 
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Drumguy999

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Yes. Stock size. According to the dealer it's in between the tccm and the transfer case. Which by the symptoms makes sense but how do I suddenly get "bad wires"?
 

smurfslayer

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m then told it IS actually the wiring and they need to pull the dash out to investigate, but this isn't covered under warranty. At this point theyve had my truck over a month, spent days trying to look at diagrams and pin outs, and I tell them to give it back because Im done dealing with them at this point.

You’ve got a powertrain issue, and a valid powertrain warranty. In what reality is the component causing the powertrain failure somehow NOT a covered powertrain component?
Do you have any DTC’s?

I take it the truck is not tuned, no suspension mods, no power train mods / otherwise very close to stock since warranty is covering this. That said, have there ever been any powertrain mods that you’re aware of?

How about stuff behind the dash, where the stealership says the issue is?
Have you opened a case with ford customer service?
 
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Drumguy999

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You’ve got a powertrain issue, and a valid powertrain warranty. In what reality is the component causing the powertrain failure somehow NOT a covered powertrain component?
Do you have any DTC’s?

I take it the truck is not tuned, no suspension mods, no power train mods / otherwise very close to stock since warranty is covering this. That said, have there ever been any powertrain mods that you’re aware of?

How about stuff behind the dash, where the stealership says the issue is?
Have you opened a case with ford customer service?
if im being frank, i think the dealership is just saying that to get my money. the truck has no mods outside of front collars, a FMIC (no tune), and a subwoofer install. All they can come up with is to blame that when the amp wire was installed, other wires in the bundle got 'cut' somehow.

this however, is the same dealer who said they replaced the vct solenoids, but did not do the cam phasers, but then cam phasers showed up on my invoice and suddenly they are done? and they also put over 50 miles on the truck (even though the invoice only says 14!) and added 2 nice scratches on my doors.

my trust in their customer service is even worse than my trust in their ability to diag it properly. so if anything, i'll bring it to another dealer and see if they'll be better to work with, but i do NOT want my dash taken out on the slim chance of 2 wires being shorted. I feel like i can diag it myself without going through all of that.

I haven't opened a case with ford customer service and honestly i didn't know that was a thing until i started reading around here.
 
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