2016 F550 4WD Problems

[PaulZ]

Hoping someone can shed some light on this. I'm in a fire dept., we have the above rig. Today some of the crew were out in the hills, going between 2wd and 4wd. They got back and said it would no longer go into 4wh. I got in sure enough, but after several attempt I did get it into 4wh and also 4wl but only for a brief few tries, then it quit going in again. This has a manual lever going into the T case, not a knob on the dash (like my Ranger). It's a 6.2L auto trans. The lever feels like it's going in, you can feel the detents, but it just freewheels. Also when it did work for me the 4WH and 4WL lights were working on the dash (and the TCS, traction control) said it was off.

Any help?

 

[Dirtman]

Are you putting the transmission in neutral before you're shifting from low to high or high to low?

 

[Uncle Gump]

I'm sure @snoranger can shed a little knowledge on this one.

 

[Snoranger]

On a manual t-case f550 it should have manual hubs, not the vacuum operated ones. (It uses the same knuckles and vacuum seals, but the ports are capped and the actual hub it’s different.) With the hubs engaged, you should be able to pull it into 4wd while parked or driving. If it’s nots going into gear, I would start by checking the external linkage for damage (bent, rotted, worn/cracked/missing bushing).

I just got home from a 24 hr shift... I’m going to take a nap and I’ll get back here later.

 

[PaulZ]

Thanks guys. It has manual hubs. Yes, shifting it while stationary, in neutral, engine running. I crawled under it briefly, linkage looks fine and again you can feel the detents (I assume they are in the TC) when you shift it.

A bit perplexing since it works sometimes. I'm familiar with my Ranger's electric motor controlled TC not working occasionally, kind of like that only with manual linkage.

 

[PaulZ]

Thinking about it a little further, again when it did go into 4WH the light on the dash came on (and did not when it didn't work), so wherever that switch is located might be a clue as to what's going on.

 

[Snoranger]

I haven’t had any transfer cases that new apart, but if it’s like the older ones It could be a worn out/ damaged shift fork wear pad or bent/broken shift fork. It does sound like it’s an internal issue.

I’ve got a 2016 F 550 transfer case at work with under 5k miles on it...
If you’re anywhere in New Jersey. I can’t sell it to you, but since we’re a government agency and it’s for a fire dept. We could probably give it to you.

 

[PaulZ]

Thanks snoranger. I'll get under it again Monday for a better look. So if I disconnect the shifter rod at the transfer case I should be able to shift it at the lever, and if that doesn't work it's something inside? And the case has to come apart to get to the shift fork? Some of the guys are pretty rough on things, I wasn't there to see how hard they tried to force it. Also curious to know where the switch is for the dash lights is, since that's not working unless it happens to go into 4WH.

I'm on the other coast but thanks for the offer. If it's not something I can fix from the outside it'll probably go to the Ford dealer.

 

[Eddo Rogue]

Maybe drain the oil and see what it looks like. Fresh oil might help. Besides that might be worn/broken forks or synchros...

 

[PaulZ]

Hey, sorry late getting back to you guys. So I came in Monday, fired it up and it went in 4WH and 4WL every time I tried it. So it's a mystery, heat related maybe,..

Thanks for all the replies.