Stuck in 4LO - ATP Light? No go?

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glenski_31
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Joined: Thu Nov 26, 2015 5:18 pm

Stuck in 4LO - ATP Light? No go?

Postby glenski_31 » Fri Dec 29, 2017 2:20 pm

Hi Guys,
Freezing cold here in Canada for the last week, haven't driven Pathy in a 4 days (4WD was left in Auto mode), start it up and go to leave and notice the diff symbol in the 4x4 is filled in, in the dash so that means 4WD not Auto?, move the switch between auto and 4WD and nothing changes on dash, so put in neutral and put into 4LO and that's when everything goes nutz.
Now no more beeps from 4WD selector button, flashing 4LO in dash, makes horrible noise in park with engine running and ATP light is now on. R, N, D, none of the gears will let it go anywhere. Crawled underneath and tried to move front driveshaft and it appears to be locked in with rear meaning T-case is stuck in 4LO? and yet when I put tranny in gear it won't move.
This is weird, I am assuming it is water somewhere that froze up in the T-case maybe?
Help would be great. I am thinking to try heating up T-case with heat gun and try it once everything is nice and warm, looks like there are multiple sensors there and maybe one of them has water in it and it froze up?
Help please and thanks
Glen


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Touchdown
Posts: 358
Joined: Sat Feb 04, 2012 2:45 pm
Location: Dallas Area

Postby Touchdown » Sun Dec 31, 2017 11:25 am

Sounds like the fluid in the transfer case or rear might have frozen.
I would try the heat gun and hopefully that works.
If that's it, a fluid change might be in order.

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smj999smj
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Postby smj999smj » Sun Dec 31, 2017 12:04 pm

You might try letting it idle for awhile; the electric pump for the wet clutch runs at idle, which should warm the fluid some. You could also perform the 4x4 self-diagnostic procedure and check for stored codes:

1. Warm up engine.
2. Move A/T selector lever to “P†position.
3. Turn 4WD shift switch to “2WD†position.
4. Turn ignition switch “ON†and “OFF†at least twice, and then turn ignition switch “OFFâ€.
5. Turn 4WD shift switch to “AUTO†position.
6. Turn ignition switch “ONâ€. (Do not start engine.)
7. 4WD warning lamp ON.
If 4WD warning lamp does not turn ON, refer to TF-122, "4WD Warning Lamp Does Not Turn ON" .
8. Move A/T selector lever to “R†position.
9. Turn 4WD shift switch to “2WDâ€, “AUTO†and “2WD†in order.
10. Move A/T selector lever to “D†position.
11. Turn 4WD shift switch to “LOCKâ€, “AUTO†and “LOCK†in order.
12. Move A/T selector lever to “N†position.
13. Turn 4WD shift switch to “AUTO†position.
14. Move A/T selector lever to “P†position.
15. Read the flickering of 4WD warning lamp.

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Touchdown
Posts: 358
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Location: Dallas Area

Postby Touchdown » Sun Dec 31, 2017 12:39 pm

smj999smj - Thank you for always sharing lots of great knowledge, however
with the state of his gears and axles frozen and/or bound up, I'm not sure making all those gearing moves would be a good idea.
I'd recommend getting towed to a local shop and get the codes pulled from there. Most shops will pull the codes for free and if he needs any work, it'll already be in the right place.

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smj999smj
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Postby smj999smj » Sun Dec 31, 2017 8:57 pm

Touchdown wrote:smj999smj - Thank you for always sharing lots of great knowledge, however
with the state of his gears and axles frozen and/or bound up, I'm not sure making all those gearing moves would be a good idea.
I'd recommend getting towed to a local shop and get the codes pulled from there. Most shops will pull the codes for free and if he needs any work, it'll already be in the right place.
None of the gears or axles will be moving as the vehicle is not driven during the self-test. It's basically an operational pattern employed to get the 4x4 control unit into self-diagnostic mode so you can read codes.

glenski_31
Posts: 26
Joined: Thu Nov 26, 2015 5:18 pm

Postby glenski_31 » Mon Jan 01, 2018 1:00 pm

smj999smj wrote:You might try letting it idle for awhile; the electric pump for the wet clutch runs at idle, which should warm the fluid some. You could also perform the 4x4 self-diagnostic procedure and check for stored codes:

1. Warm up engine.
2. Move A/T selector lever to “P†position.
3. Turn 4WD shift switch to “2WD†position.
4. Turn ignition switch “ON†and “OFF†at least twice, and then turn ignition switch “OFFâ€.
5. Turn 4WD shift switch to “AUTO†position.
6. Turn ignition switch “ONâ€. (Do not start engine.)
7. 4WD warning lamp ON.
If 4WD warning lamp does not turn ON, refer to TF-122, "4WD Warning Lamp Does Not Turn ON" .
8. Move A/T selector lever to “R†position.
9. Turn 4WD shift switch to “2WDâ€, “AUTO†and “2WD†in order.
10. Move A/T selector lever to “D†position.
11. Turn 4WD shift switch to “LOCKâ€, “AUTO†and “LOCK†in order.
12. Move A/T selector lever to “N†position.
13. Turn 4WD shift switch to “AUTO†position.
14. Move A/T selector lever to “P†position.
15. Read the flickering of 4WD warning lamp.
Thanks guys for the replies. I had a little brainwave after reading through how the XFR case works in the service manual, it seemed like I was stuck somewhere between 4-LO and a false neutral that was causing a bunch of sensors to go nuts ATP etc...it felt very much like a mechanical issue. So I took my farm jack and jacked up the back of the Pathy and spun one of the rear wheels and it felt like things engaged. This was of course after checking all the easy electrical stuff like fuses etc. and following more or less what you described above. Started it up with the vehicle in neutral and switched the dial over to 4LO and felt the sound of 4LO engaging and then back through all the 4WD modes back into 2WD and away I went. All lights gone from dash and problem solved.

Another follow up: The cold snap continues and so this AM I went out to start the Pathy (-21C) and I had left it parked in AWD 'Auto' and I noticed that the dash symbol indicated a locked diff 4HI, which is exactly what triggered the events of this post and made me put Pathy in neutral and switch to 4LO which never actually engaged.

Conclusion is that the electric pump for the wet clutch is dealing with very very cold fluid and so even though the XFR case is supposed to be in Auto the clutch doesn't have warm enough fluid to be able to function in Auto. So after warming up for a couple of mins the pump XFR case will happily go to Auto.

All this to say I don't think there is anything wrong with the Pathy, it is just that we haven't had a deep cold snap like this where I haven't driven it much. Once everything is warmed up the XFR is works like a charm...

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Touchdown
Posts: 358
Joined: Sat Feb 04, 2012 2:45 pm
Location: Dallas Area

Postby Touchdown » Mon Jan 01, 2018 6:58 pm

Glad to see you got it working!!
No experience with that kind of cold of weather & the pathy here in Texas, but good knowledge to have.


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