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Well I have a code P1728 flashing. From what I can find this is a trans slip code and slipping in the Torque converter. I don't notice any problems driving. How it started...
I was towing my travel trailer the other week when it was very cold and icy. I was in 4wd and going 15-45mph depending on conditions. I towed it about 15 miles and I don't know at what point the light came on. I just noticed it flashing. I drive with my arm in the way of the light.
I cleared the code and put in 2wd. Drove it the next day and the light came back on. Then I noticed the volt guage on the dash low. Diagnosed and found the alternator went out. I didn't notice if it was low the day before. So I put and alternator in it and now is working good. I also put truck back into stock mode. It was in tow mode. I have the edge evo.
I drove for about 6 days all ok then the code came back. I can't find any diagnostics for this code. sounds like I need to replace the torque converter. At 150k does anyone have any input on what to check or do? Or am I stuck with replacing the converter at a quoted $1400.00 that comes with a new solinoid pack? If thats the case would it be better to just replace the trans and converter since the trans is comming out anyways. I don't tow that much.
What about draining the converter and pan and refilling with new fluid? I replaced the filter and fluid a year ago but I didn't drain the converter. I have fixed chattering problems this way so I was thinking it might work?? The fluid does look ok right now. Thanks
Also any recomended trans shops in the Everett Washington area?
 

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Having this same problem after a supposed rebuild job with a new tc.. I can drive for about 30 mins before the light comes on and starts to shift harder .. from what I've read an been told it's from dirty fluid or a jacked up converter so ig I'll start with the converter...btw I drive a 98 navigator with the e4od
 

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You can change the fluid, but I don't see that helping this problem at all.

The only way I can think to diagnose this is with Forscan. Watch a parameter called SLIP_ACT. When the torque converter should be locked this should read less than about 15 RPM. If it reads over 50 RPM the converter clutch is slipping and will set this code.
 
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[hijack?]
You can change the fluid...
I want to change mine because I assume it's the factory fluid (the brakes were). But the only local Ford diesel tech I trust told me not to risk it. I haven't talked to the only local Ford transmission tech I trust about it, but I'd trust your advice. I added a Hayden cooler & magnetic FilTran several months ago, but not very many miles, and only ~60mi towing light. Now that the MLPS is good, the truck has no symptoms specific to the transmission (just some bucking at WOT), and I'm getting a strong itch to change the fluid/filter/pan/gasket (all new Ford/MC on-hand).

Do you think it's a good idea? Is there a specific procedure you recommend (driving XXX miles; changing fluid hot/warm/cold; waiting for Spring; refilling off/idling; additives...)? I have access to a BG 20qt flush machine - the kind plumbed into the cooler loop with a diaphragm in its reservoir, driven by the transmission's internal pump. But since I want to change to the later pan with factory drain plug, and the filter & gasket, I had planned to punch a hole in the pan to drain it (maybe add a drain plug to the old pan later), and then refill through the dipstick.

[/hijack]
 

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If the trans is in good shape new fluid can only help it last longer. If it's already damaged new fluid won't fix it. I strongly recommend changing the fluid.

Here is how to change the fluid: Trans fluid change.

The BG machine is also a good way to change it as long as you don't add the chemicals. Just remove the old fluid as the machine adds new fluid.
 
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Thanks. The BG machine doesn't actually do anything; it's just a reservoir with a diaphragm that pushes the clean fluid in as the old fluid comes out, so the level never drops or changes. But I won't be using it since I'm changing the pan. Is the pan the best place to measure ATF temp? Should I weld in a bung for a gauge now, before the new pan is installed?
 

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The pan is the second worst place to measure the trans temp, only better than measuring the temperature in the cooler lines.

Put the sender in the test port on the driver's side of the trans. It is a 1/8" NPT dryseal thread, which fits almost every sender.
 
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Thanks. All the pics are gone from your old article, and I'm not sure where the bypass line or banjos that you mentioned are (all my previous E4ODs have common inverted flare fittings); it only says to disconnect the return line at the trans, so I don't understand why a bypass line would be open to release fluid. After re-reading a few times, it seems like that article is written primarily for the later 4R100, and mine won't have the bypass or banjos. Does that mean it's OK for me to do all my work at the front of the truck, where the rubber line & Magnefine go? But I'll try to get several good pics that might be added back into the article. Neither of these shows the right side:

(click this text)


(click this text)


I think your procedure for my situation is:
1) operating temp
2) drain/drop the pan/gasket/filter; install new ones
3) add 7qt into the dipstick
4) pull a rubber hose near the grill, put the flow side into a bucket
5) idle 1.5gal (6qt) out while shifting through all ranges
6) add 6qt
7) idle 1.5gal (6qt) out while shifting through all ranges
8) add 6qt
9) new Magnefine & reconnect the hose
10) test drive & top up
Does that look right? Based on your numbers & math, it seems like dropping the pan dumps 16qt, since only 3 other qts are removed; but 19 are put in.

Your article doesn't mention why you change the pan filter so often (do you tow a lot?), or how often you change the Magnefine (do you follow Ford's 30Kmi schedule, Magnefine's, or your own?).
 

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Dropping the pan will get about 7 quarts, not 16. Disconnect a cooler line anywhere that is convenient. Idle the engine until you get an air bubble then shut it off. That should get about 6 quarts, not 1.5. Add however much came out, then idle the engine again and get another 6 quarts or so.

I've changed my mind on the filter. It doesn't need to be changed until the transmission is rebuilt.
 
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OK I re-read it again, and see now that step 6a is the only one that uses GALLONS - the rest of the instructions are in quarts. What about the external inline (MagneFine) filter interval?
 

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I don't know the change interval on the Magnefine filter.
 

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I found it in the TSB: 30Kmi (48K Km).

I changed the pan & fluid this evening your way. The pan looked like it had been undercoated inside, and the magnet was almost unrecognizable.

(click this text)


I also put in a new magnetic filter.

(click this text)


I let it idle in the shop to bring the temp back up for checking the fluid level, but I haven't driven it yet. I have a 3-gauge pillar & the gauges on the way, so I'll try to clean the grime off the Left side of the trans before installing that temperature sender. Should I expect much fluid to drain when I pull that plug?
 

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You'll get an ounce of so of fluid when you remove the plug.
 

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Thanks. The level is slightly high after some driving & idling today, so I'll pull some out soon.
 

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Having the inline filter up high made it really easy to pump some fluid back into a bottle.

(click this text)


There was a new odd harmonic humming sound at ~45mph that had me terrified that the trans was not liking the new fluid. But it turned out that I hadn't unlocked the hub that I was using to check the front U-joints.
 

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Mark
Is it possible for the fluid change alone to dramatically affect the shift behavior? Seems like I remember you answering that question months/years ago, but I don't remember what you said, and I haven't found that post (if it was even on this forum). Since I bought the truck, the 1-2 shift has been fairly smooth but still noticeable; the 2-3 & 3-4 shifts have been consistently HARSH, and that continued through all the other little problems I've been working out of the truck. But after the fluid/filter/pan/inline-filter change, the 1-2 shift has been consistently unnoticeable, and the others have been consistently mild to the point of being almost unnoticeable.
 

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Yes, new fluid will do that. The friction modifiers in the fluid will wear out and make the shifts harsher.
 

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^ (y) Steve, I also noticed how much smoother my shifts were after following Marks flush procedure with Mobil 1 ATF a couple years ago.
 

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Good to know - thanks. Do you think the trans would benefit from another fluid change in a year or so?

The 3 gauges have arrived, so I'm getting really close to changing the dash and rewiring it for them, RKE/Start, USB power, TPMS, & a few other additions.
 

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I recommend changing the ATF every 30,000 miles.
 
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