2007 Limited 4.6 (Surging or Pulsing?)

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Daniel Humbert

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I have a 2007 trac with a 4.6 4x4 with 6r60 trans. I bought the truck used a few months back and I am having some sort of issue I cannot seem to find an answer for. While driving the truck at around 40-60 (give or take) the truck rpms seem to surge up. I barely have my foot on the throttle and nothing is changing. It will go from around 1150-1200 rpm to around 1300-1350 (again give or take) for a split second and then right back down. Whilst this happens it seems to have something that feels like torque shutter but only when this happens. If I gas it it will go right on no hesitation. If I turn O/D off this doesn't seem to happen. Possibly because the RPM at that speed is around 2k not 1.1k.



Things I have replaced so far (new parts)

1 Plugs

2 CoPs (all 8)

3 Injectors (all 8)

4 Fuel Filter (twice)

5 TPS

6 Pulled the throttle body and cleaned around it

7 Beating my head against the wall

8 Voodoo and small animal sacrifice

(7 & 8 were my last resort)



Any help into this would be great. If I left something out or need to explain it better please let me know.
 
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I had a similar problem with my previous 07 V6 Trac. Fix that finally worked was updating the transmission program at a local Ford dealership. Cost was approx $100.
 
How many miles on vehicle? How many miles since transmission service? It sounds like the clutch in the torque converter is unlocking and locking. It is probably in sixth gear by then and feels like it is have a hard time with torque output and rpm level. My truck usually doesn't go into sixth til at least 45 mph or so. It sounds like the fluid/friction modifier is gone in it. The fluid could still be red/dark red and the friction modifier be gone. The shuddering is most likely from that. I would suggest a fluid and filter change. Make sure you use Mercon SP or LV. If you service it, Oreilley auto parts sells Motorcraft stuff and can get it pretty fast and cheaper than Ford sells it at.
 
Possible the torque converter solenoid. It is suppose to lock the torque converter @ 45mph. For 0 slipage and 1 to 1 ratio. It might be malfunctioning.



Not all O'rielys stocks motorcraft trans fluids. A member and friend on this board. Can get it @ his O'rieys. We only found it @ an independent on my side of town.
 
Truck has 81k. I forgot to mention that I had the hard downshift problem and had the trans control updated. I was afraid that it was the converter. Since its a 6r60 trans should I have it flushed? It's not one I can change the fluid in myself. Also someone else had told me a possible solenoid but I couldn't find much info on that. Don't know if that's something I can change or if I need to take it to a trans shop.
 
Also I have been told never to "flush" a trans that it will destroy it. What's your opinion on that. I hate to pay 200 to have my trans destroyed. Or should I try and drain it and then run it for a couple days and drain it again and again until it looks like I have gotten most of the old fluid out? Thinking more about it, it might be broken down fluid it seems to work fine until you get 10 mins down the road (until the fluid is warm)
 
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Flushing will not destroy a trans.



Now that that is out of the way it sounds like you are having an issue with the torque converter staying locked up as Eddie has mentioned. Realistically your only option being that #8 on your list didn't work (has always worked for me in the past) is taking it in and having it diagnosed. With a scan tool hooked to it they will be able to monitor torque converter clutch solenoid commanded percentage and torque converter slip speed to see if the converter is actually dropping out or if something is causing it to drop out.



Just out of curiosity does this happen only with the ac on? I have seen these symptoms on vehicles with low refrigerant charge as the ac compressor cycles excessively when the system is low.
 
Unless you've installed a drain plug (a good idea) or an aftermarket pan (also good but more expensive), the only way to drain the trans fluid is to drop the pan. Messy. Have you checked the fluid level? It's not easy - there is a small dipstick on passenger side of the transmission - in close proximity to the exhaust. Search net or YouTube for the procedure. Dealership service is probably best, but a competent quick lube should be able to service your transmission properly. As far as advice on whether to service a transmission, you'll generally find two camps: 1) Don't touch it until it fails, and 2) Service your tranny on a reasonable schedule with OEM or top-tier synthetic fluid. I'm in Camp 2 and use AMSOIL.
 
Well it seems to have taken care of it. The tech said the fluid was a little burnt looking and smelled some. They also suggested that the filter be replaced (I thought that was included in what they quoted me) $302 later and it shifts smooth as silk and the shutter is gone and the engine seems to be working itself out. The rpms jump a little bit now (25-30) but even that seems to be getting fewer between each time. I'm cautiously optimistic right now.
 
Well I may have spoke to soon. The surging still seems present, however the shutter is 100% gone. Could this be still in the torque converter? Only thing that is not stock on the truck is exhaust. It has a catback single flow master on it. It may also have a small manifold leak. Thanks again.
 
Memphis, did you get this problem sorted? I have the exact same issue on my 07 Limited. I had it at the dealer yesterday and they found nothing electrically, plugs and coils had all been recently replaced. Given I'm at 139,000 miles the did a tranny service. Just like yours that took care of the shudder, but I still have the slight RPM surge at 1250 RPM's. I would sincerely appreciate it if you would share the fix.
 
Sounds to me like the transmission torque converter is going in and out of lock up. Need to get a scan tool that can monitor transmission input rpm, output rpm, lock up solenoid command and torque converter slip rpm to see if this is actually what is going on or not. If the torque converter lockup solenoid is being commanded on and off while at a steady cruise then the fun part is figuring out why. Usually this is caused by a faulty tps or in some cases a fault with the charging sytem.
 
I data logged my truck, got a lot of data I am not real sure what to do with. Here is a screen shot of what it looks like while it is doing its thing.

Blue is "Actual slip across torque converter"

Gold is "Filtered engine speed for trans"

Green is "TQ desired from AM"

The rest of the data did not seem to correlate with the surging so I unchecked it. I have the 16mb CSV file that my SCT tuner made during data logging. (the tuner is for a different vehicle the ST is on the stock tune)



a0df9b8cc1c337fc0ca71d439b23f269.jpg


 
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To check for torque converter slip you would need to monitor trans input shaft speed, output shaft speed, tcc slip rpm, and tcc solenoid command. The tcc solenoid command is huge, without it we do not know if the pcm is commanding tcc lockup or not so any other data is basically useless.
 
I do not have Input shaft speed. I do have output shaft speed. The only command I can find in the list is command gear. I assume that is current trans gear. I have a few spots for solenoids but I am not sure if it is what you are looking for. The output shaft speed does not go along with the sign wave part that is the pulsing, it stays steady around 1700(ish) rpm while it is doing it. This is what I have listed that I could find for transmission. If any of that helps you at all. I have uploaded the datalogs, if you can make more use of them, I wish I knew as much about vehicle computers as I do about personal computers. Let me know if you would like the files they are in .CSV format and I am using LiveLink from SCT to open them.





Time (sec) ACTUAL SLIP ACROSS TORQUE CONVERTER|2|224|2|0 ANTI STALL MULTIPLIER|2|224|2|0 battery voltage|1|225|33|0 clutch pedal position|1|224|2|0 codes pending codes|1|225|52|0 commanded gear|1|224|2|0 commanded gear|1|225|2|0 COMMANDED GEAR|2|224|2|0 converter clutch current|1|225|77|0 engine load|1|225|6|0 FILTERED ENGINE SPEED FOR TRANS|2|224|2|0 GEAR RATIO ACROSS TRANSMISSION|2|224|2|0 NEUTRAL DRIVE FLAG|2|224|2|0 OD cancel on|1|224|2|0 OUTPUT SHAFT RPM|2|224|2|0 output shaft speed|1|225|29|0 output shaft speed|1|225|29|0 PRNDL position|1|225|33|0 rpm|1|225|29|0 SHIFT IN PROGRESS FLAG|2|224|2|0 SHIFT POINT CALCULATION SOURCE|2|224|2|0 shift type|1|225|2|0 SHIFTER POSITION|2|224|2|0 solenoid A current|1|225|77|0 solenoid B current|1|225|77|0 solenoid C current|1|225|77|0 solenoid D current|1|225|77|0 solenoid D pressure|1|225|12|0 TORQUE AT FLYWHEEL|2|224|2|0 torque converter sli|1|225|29|0 torque into converter|1|225|42|0 TORQUE REDUCTION FOR TRANS SHIFTS|2|224|2|0 TQ DESIRED FROM AM|2|224|2|0 trans gear ratio|1|224|2|0 trans temp|1|225|10|0 TRANSMISSION OIL TEMP|2|224|2|0 TRANSMISSION TURBINE SPEED|2|224|2|0 turbine shaft speed|1|225|29|0 turbine shaft speed source|1|225|29|0

 
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