2012 Lincoln Navigator - 6r80 - 235k miles - possible trans slip

chackett

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Dec 9, 2020
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Make
Lincoln
Model
Navigator
Year
2012
Miles
235,000
Engine
5.4l 3v Ford
Hi All-

I've got a 2012 Lincoln Navigator with the 6r80 trans in it with ~230k miles on it. I recently had the timing chain, guides, tensioners, cam shaft phasers, etc. done and now I'm experiencing what feels like a trans problem. I have had ignition coils go bad and I've already checked for any misfire codes, so I think I'm ok there.

The symptom is that under very light load the trans feels like it's "hunting" or "confused" about wether it should downshift from 6>5. The scenario is that I'll be driving along at say 55 mph in 6th. I'll come upon a slight incline and the load will increase very slightly, and at this point (sometimes, not always) the vehicle feels like the trans is slipping or halfway downshifting but then changing its mind .. it's not quite a shudder. More like a "bump". Any slight depression on the gas to increase the load will cause a smooth downshift and the problem goes away.

There are no standard codes, and I've been trying to find a way to check for trans codes. Forscan doesn't seem to do it, although it does seem to be able to clear the adaptive tables, but I don't know if that's a good idea or not.

Oh .. and I have already done the moulded leadframe replacement which I understand was a pretty common problem. I did previously have some codes related to the output speed sensor / mismatch, but haven't seen anything in ~80k miles related to any of that.

I'd sure be grateful for any pointers, hints, questions. Thanks so much!

Chris
 

NickD

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Must be a road salt free area, if that car was up here in road salt country would be a pile of rust a long time ago. Coolant lines can be dropped for a complete flushing and all new AT fluid may help, but these things do wear out.
 

chackett

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Must be a road salt free area, if that car was up here in road salt country would be a pile of rust a long time ago. Coolant lines can be dropped for a complete flushing and all new AT fluid may help, but these things do wear out.
Indeed :) I'm in Atlanta. The vehicle is in pretty good condition and even though it's got the somewhat problematic 5.4l 3v engine, it's been a very reliable and good vehicle. I just had the timing chain / guides / tensioners / cam shaf phaser job done on it, and the engine sounds and runs as new. So I sure hope I can get to the bottom of this issue. I'd love to be still driving this at 500k miles :)

My next step was to at least drop the pan and change the filter and fluid in the pan. I'm just an amature, so I figured I'd at least try and get some input from folks in the know before I go willy nilly doing stuff with no real idea if it's actually a good idea or not :)
 

billr

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Be patient for our trans expert to chime in here with something useful. If he doesn't show up by tomorrow morning, I will summon by private messaging.
 

chackett

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Be patient for our trans expert to chime in here with something useful. If he doesn't show up by tomorrow morning, I will summon by private messaging.
Thanks billr, I appreciate it. I'm not in a huge hurry, so I can tough it out for a few days :)
 

JackC

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Chris: That might be the torque converter clutch "hunting"(off and on) under those slightly different conditions. . I am not familiar with your vehicle, but on my car that hunting annoyed me enough to install an on-off switch on the TCC so I could disengage the TCC lockup when driving under conditions like you describe. BTW, I never use it anymore, I just live with it. So, I am saying it might be normal.

On the other hand, since you have had this car a long time, I assume this is a new problem and my idea is probably bogus. Just a thought that came to mind.. You may be able to disconnect the TCC by removing a wire for a short test to see if that helps. Again these are just thoughts and I do not know your vehicle at all.
 

grcauto

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I agree with jack. TC is locking and unlocking. The number one input the PCM uses to apply or release is the load. When you are on the edge it can oscillate. Just drop it into 5th until your driving conditions improve.
 

NickD

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Brains are in the ECU gear shift lever mechanical function is to slip the parking pawl in a toothed gear for park, shifting goes though what they use to call the neutral safety switch whose contacts can get dirty engaging or disengaging many solenoid activated hydraulic valves for the different combination of forward gears, neutral or reverse, one of the valves is for the torque converter lock up.

Have an engine driven fluid pump to provide the hydraulic pump typical of around 150 psi. Have a normally closed switch on the brake pedal that when you step on the brake open that switch that disengages the torque converter lockup, that can have dirty switch contacts.

Adding the wrong fluids can stall the operation of these hydraulic valves so they do no instantly respond when engage or disengage so you can have two or three valves fighting each other. Also have a cable from the ECU thought that netural safety switch on only for the starter but all those solenoid valves with poor connector pins.

Lastly code is store in flashram, some bytes may be lost causing shift problems, need a reload, electrical glitches can cause memory lost problems.

Met more people screwed because a shop said they need a new 4000 buck AT when they had minor connector or swtich problems. Could always take these apart and clean the contacts. Another problem is made in China.
 

Alcan

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Start by verifying you're not feeling a transmission symptom related to an engine drivability problem.. Have the MAP and MAF sensor inputs checked, Could be marginal manifold vacuum input to the PCM at the vehicle mileage you state.
 

bp042665

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ok have you had fluid checked to make sure it's full also do you have a tow haul button if so try putting it in tow haul and see if problem goes away this unit on a ford dont have a dip stick for-say it has a plug on passenger side of transmission with the stub stick inside it i have seen this transmission going out around 110K to 220K depending on drive style at my shop
 

NickD

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Start by verifying you're not feeling a transmission symptom related to an engine drivability problem.. Have the MAP and MAF sensor inputs checked, Could be marginal manifold vacuum input to the PCM at the vehicle mileage you state.

Sure is possibility mistaking a shift problem for an engine misfire, engine is put under load when up shifting. Been listening to symptoms all my grown life, but being there is a much different story.
 

JackC

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Alcan's info should be considered for sure.

I had one bad spark-plug trick me and my friends at their trans shop think the TCC was bad when it was only a plug misfiring when under more load when the TCC locked up. So, a test would be to disable the TCC as I stated above.
 

chackett

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Wow .. ok. Thank you for all the really helpful and insightful replies. I apologize that I haven't' responded, but for some reason I didn't get any notification that there had been replies. I only visited today to see if I could ressurect the thread.

I will try to address whatever items or questions came up. And please keep in mind, that I'm truly just an amateur and haven't done anything technical beyond changing the moulded lead frame on the valve body or pulling codes with a cheap OBDii connector and something like forscan.

1. JackC mentioned it might be the TCC, and I'm absolutely willing to give turning the TCC off to perform a test. I can clarify slightly further to say that A) the issue does not occur 100% of the time. Many times it will behave totally normally . .and B) I have driven this vehicle for roughly 150k miles and I know it pretty well. This is definitely a new problem I haven't experienced before. I do not know how to locate the appropraite connections on this (or any) vehicle in order to temporarily disable the TCC.

2. I am definitely interested in NickD's comments regarding potentially dirty connectors or contacts and I would love to remove and clean them, ut I'm not sure where or how to start on that. I have dropped my pan and replaced the trans fluid filter and removed the valve body and replaced the leadframe, but beyond that I'm not sure where or how to access the various contacts and connectors you might recommend replacing. I'm happy to pay a professional, but I do enjoy learning and doing things myself, and as you said many people get screwed into a new trans when something minor could have fixed the problem (at least for a while) until a legit rebuild is actually needed.

3. bp042665 - Thanks. I do indeed have a tow/haul button but I haven't tried pressing it to see if it has any affect. I'll do that and report back. Also yeah, there's no trans fluid dipstick other than the one on the side of the pan. I will crawl up there and check it. Should I check it hot or cold?

4. NickD and JackC - I have in the past experienced the symptoms of a bad ignition coil or pack which made me believe I had a transmission problem, only to be relieved to learn it was just a bad coil or bad pack. I was VERY hopeful that would be the case again. I used forscan to try and view live data to see if I could correlate the drivability problem with an indicated misfire, but I couldn't do it. I know it's possible to have a misfire condition where there is no code thrown, but I feel like the problem is severe enough that sure a code would have been thrown by now, but I accept that I could be totally mistaken.

I guess what I need to start with is the easy stuff I know I can do. Check the fluid level, try the tow/haul button. Then try and figure out how I might perform a test to prove or eliminate the TCC. Someone will have to guide me or at least point me in the in the direction where I might be able to figure it out on my own.

Sincerely - thank you for taking the time to offer your comments and ideas, I really do appreciate it. Thank you.

Chris
 

JackC

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Chris: I can not tell you HOW to temporarily disengage TCC on your car. Hopefully someone can jump in and tell you. That would be a nice no cost test to get you started.
 

billr

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If Forscan does not give trans codes, then it probably doesn't provide trans live-data either. It would be wise to upgrade to something that handles the trans stuff! You want to see (in live-data) what "gear commanded", "gear selected", "TCC lock", and "TCC slip" are doing while the 5-6 shuffle is going on. For example: if "gear commanded" is flitting back-and-forth consistent with the perceived shifting, then the trans solenoids and hydraulics are simply responding normally and are fine. Some of those data-fields might be labeled different on whatever HW/SW you use to display, but there should be equivalents. You can save a lot of guessing, testing, or (*gasp*) parts-swapping by using live-data.
 
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