Hi guys! I have an 08 F150 XLT 4x4 with 5.4 Triton.... that has thrown a Trans Fault with flashing O/D light and CHK Engine light. Now, this happened about 4000 miles ago when I was pulling a trailer up the mountain. The tranny didn't get hot, but I flushed it anyway by pulling the return line... running 3 qts out, refilling drain pan, and repeating untill all old fluid had been flushed from tranny, torque converter, cooler, and lines...

It ran well for 4000 miles, then today... got the same Trans Fault with flashing O/D with CHK Engine Light .... So, stoped in at Advance... they read the code... and showed the "Shift Solenoid" was out...

My question... where is this thing at and how big a job is it going to be? I thing it's in the throttle body, but not sure which one it would be.... and if I should replace any other solenoid I find on the throtle body.

Anyone had this problem before?

Any help would be greatly appreciated.

 

The truck currently has 68K miles on it... and the fluid level is good and clean...

 

Anyone?

 

Well, dove into the project today. The Auto Trans Shift Solenoid is a dual solenoid...
Everything from erratic voltages to improper fluid level to trash in the fluid can cause the same problem as a faulty shift solenoid…
In my case… the solenoid was indeed faulty. I dropped the pan, popped off the plastic wiring harness, removed the two bolts that held the shift solenoid in, cleaned the throttle body, installed the new solenoid, reinstalled the wiring harness bracket, cleaned pan and magnet, added new filter, gasket, and synthetic fluid… and all is well…
I warn you though… if you have an O8 with this same problem, and you tackle this yourself, understand the part number on your original shift solenoid has changed… and the guys around my parts had difficulty getting it right… just so you know.
Took my time and got the job done in an hour…

The original part# 6L3P-7G484 AB
New part# 6L3Z-7G484A

Carquest part# ECC 57-6584

 

This is doubtlessly a 4R70W (family) transmission, but take it from a tranny tech; this may come back.
This was not the best transmission once they had problems; when the shift solenoids had problems, they tended to burn clutches really badly in this transmission. So, beware.
What were the orignal codes that you got? I'd be interested to hear, as this could denote something more serious, like TCC slippage or clutch faliure.
Please let us know!

 

I purchased the truck with 27K miles on it and it has performed flawlessly up and until the day I pulled my 6x10 enclosed up to WV. At that time, I had around 62K on it. I've pulled loads in the past, but not more than a couple dozen times and with no problems.
Total pull weight for the WV trip was around 2500lbs. Once ariving in WV from NC... (240 miles ea way), stopped, had lunch, drove about 6 miles outside of this Norman Rockwell style town, and proceeded up the mountain. There was highs and lows up the 1.5 mile climb, but didn't seem too unreasonable at the time. Just before getting to the top, the tranny threw a trans fault w/ OD flashing code. The tranny did NOT overheat though. Got to the top, turned off the truck and let it sit about half an hour. I checked the fluid, and it smelled burned. At this point, the engine light was NOT on....
I flushed the tranny in that I removed the intake line, flushe a couple quarts at a time, while adding the same back into the tranny. Of course, this was after droping the pan, cleaning the throttle body, adding new filter and gasket, and 4 fresh quarts to the tranny.
The pan had the usual black residue/fine particals on magnet, but NO chunks of metal that I could see. More importantly, the pan was also missing the factory plug... Hmmmmmm... and yes, I did buy this truck from a dealer. Notice I left the "reputal" out...
Anyway, drove the truck with no problems for about 6K miles (original post said 4K, but is wrong) until I got the exact same code. Drove to Advance to get it read, and got the shift solenoid code.
Upon checking the pan this last time, the usual black residue/fine particals on magnet was present, but NO chunks of metal. Replaced the filter and added 4 quarts of synthetic... Put about 150 miles on it and haven't had any problems. The tranny is changing very smoothly and going into overdrive much sooner than before. I guess when these types of problems happen with the shift solenoids going bad over time, the changes can be suttle enough to miss... that is.. unless you're a tranny tech

 

Since I AM a tranny tech, I was very interested in the code; Shift solenoids going bad is not unheard of, but what it really means is this:
The shift sol. A and B are monitored on the ground side at all times. The code is set when the PCM attempts to ground the solenoid, and the voltage on the circut stays either high or low, depending on commanded gear.
What gears were or were not avialible when the problem occured? This trans. isn't the best known for taking a lot of punishment, as the direct clutches (3rd & 4TH gears) were always getting burnt and going out (yes, it's at the very rear of the trans). I'd be willing to bet that you couldn't get the commanded gear, and the trans defaulted to 2nd gear (which it's programmed to do). At this point, the trans could of overheated (though it might not have boiled the oil, they do have relatively small oil to air coolers), thought it didn't set a code.
The lack of metal is a really good sign, though these trannys did leave a fairly large amount of clutch material; that was one weakness of this trans; they ate clutches fast and tended to 'whack' the drivetrain when shifted.
However, since from you post you really haven't been towing a gooseneck 5th wheel with it, I'd be willing to bet that you might have gotten lucky. I might sound like a mother hen, but if I had a solenoide go out, I'd take off the valve body and clean it up, which gives you a great oppurtunity to check out the EPC solenoid and any scoring on the press. reg. valves.
Additionally, it is common on the programming to see these drop into 4th anywhere above about 35 mph. It seems low, and it depends greatly on the gearing and programming, but it does acheive the greatest fuel economy.

 

Greasemark... if I use a meter to test the solenoids, what would the spec call for?

Like I posted, I got the shift solenoid code, changed it out, and no problems... BUT... the solenoid should be bad, so better test to make sure. Like most, I guess, I trust the code... but may be overlooking the cause... as you elude to.

Thanks in advance for your expertise in this area my friend. You've certainly opened my eyes to the possibilities...

 

Both shift solenoids should have a reading of 20-30 ohms, and both should be extremely close (within about .1-.2 ohms of each other), and most will read about 24.x ohms (in my experience). The Torque convertor clutch solenoid (the other one by itself) should read between 10-16 ohms.
I would like to point out that the moulded lead frame (the black plastic piece that links all the electricals together in the trans) had some problems with pin fit, so watch out for this. Also, when this trans would grind up a thrust bearing (the #9 bearing at the very rear of the trans was a common culprit), the metal would lodge in the frame and short out the solenoid, at least until it was removed. One other thing to look for is any wiring loom damage, especially where the branch comes off on the left side, goes over the top of the trans to the bulkhead connector.
I really hope all is good and nothing was burnt up too badly. It sounds like you got to it in time.

 

greasemark, here is the solenoid I replaced on my truck. I tested putting the black lead on the pin closest to the part and alternating the red on the other two. My results were 25.0 to 25.1 on one and 25.1 to 25.2 on the other.

Did I use the proper pin sequence?

Given theses results, I can't help but wonder why the new part seemed to clear things up. Perhaps it was the simple act of replacing 4 quarts and a filter despite having done that about 6K miles earlier.

You mentioned earlier that this tranny sheds lots of clutch material. I wonder, could that material cause the valves to malfunction over time. I'm going to pay close attention to gear changes and record over the next few days. I'll also hook my boat up and pull it down the road to see if stressing the tranny will bring the fault coade back. But, all I've done lately is drive about 150 miles a day for the last 5 weeks... on business trips...

Thanks again greasemark for your expertise....