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Drivetrain slipping?

Groover
Explorer II
Explorer II
So yesterday I was headed out to a job pulling my equipment trailer which is pretty heavy and the route includes some hills with up to 7% grades. Going up one of those hills at medium RPM but near full boost the truck bumped like I had hit a small pot hole, but only once and I was going in a straight line so I should have hit with both tires if that was in fact the case. Then it bumped again and a few more times on the way out and the way home. It did this in both 3rd and 4th gears with RPMs ranging from 2500 to 3500rpm. The bump reminded me most of when the chain on my bicycle stretched out and would occasionally slip a tooth on the sprocket. No error messages so far so no clues there. This is a little premature to asking questions but I really don't want to run to failure and end up broken down with a heavy trailer on a 7% grade.

Has anyone had a problem like this before? What did you do to fix it?

My truck is a 2016 F150, 4WD, 3.5 Ecoboost with 6 speed transmission. It could the engine, transmission or transfer case, maybe even the rear axle.
16 REPLIES 16

Grit_dog
Nomad III
Nomad III
ajriding wrote:
I would not suspect the trans for a bump, it should be the opposite of a bump if trans is going out, but I digress...

Trans fluid can be "changed" but you only change some of it, so the new mixes with the old and is immediately dirty, so unless you see burnt fluid you can't go by the cleanliness of it.
Do you monitor trans temps?

One misfire should not bump, should be barely discernible but I would surely start with the engine plugs.



Not sure where your relevant experience comes from with this advice, but suffice it to say, it's largely inaccurate on most accounts.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

Groover
Explorer II
Explorer II
I was delayed by weather and life in general but I finally got the plugs changed and took if for a test drive that included going up the same hills where it was acting up. That was running about 55mph in 3rd gear at max boost. Everything seems to be good.

I have watched the dash gage for transmission temperature before and never saw it increase from normal operating temperature. I suspect that may not be accurate but never got around to figuring out a better way to monitor it. I hope to work in dropping the transmission pan soon and replace the filter. If everything looks good I will stop with just cleaning it up and replacing that portion of the fluid.

Thanks for the help!

ajriding
Explorer
Explorer
I would not suspect the trans for a bump, it should be the opposite of a bump if trans is going out, but I digress...

Trans fluid can be "changed" but you only change some of it, so the new mixes with the old and is immediately dirty, so unless you see burnt fluid you can't go by the cleanliness of it.
Do you monitor trans temps?

One misfire should not bump, should be barely discernible but I would surely start with the engine plugs.

Mostly, you need to ask an F150 forum, we don't know much here, but do yell at kids to get off our lawn a lot. The Ford forums are slammed with lemons.

blofgren
Explorer
Explorer
Krusty wrote:
Pull the spark plugs for inspection. I suspect one will have carbon tracking visible down the side of the white porcelain insulator near where the part# is printed. This is caused by your misfire and quite common on 3.5 eco. When the plugs get worn, they are sometimes unable to fire through the high cylinder pressures when you are under load, and the spark will find it easier to jump down the outside of the plug to ground, leaving the carbon track as evidence.


This makes total sense. It seems that the DI engines eat spark plugs quite frequently.
2013 Ram 3500 Megacab DRW Laramie 4x4, 6.7L Cummins, G56, 3.73, Maximum Steel, black lthr, B&W RVK3670 hitch, Retrax, Linex, and a bunch of options incl. cargo camera
2008 Corsair Excella Platinum 34.5 CKTS fifth wheel with winter package & disc brakes

Krusty
Nomad
Nomad
Pull the spark plugs for inspection. I suspect one will have carbon tracking visible down the side of the white porcelain insulator near where the part# is printed. This is caused by your misfire and quite common on 3.5 eco. When the plugs get worn, they are sometimes unable to fire through the high cylinder pressures when you are under load, and the spark will find it easier to jump down the outside of the plug to ground, leaving the carbon track as evidence.
Krusty
92 F-250 4x4 460 5spd 4.10LS Prodigy
97 Rustler RT190
EU2000i
Garmin

Groover
Explorer II
Explorer II
I have checked for pending codes and found none then chalked the tires and found that they are not slipping. I was disappointed there as I am going to need new tires soon anyway.

The truck only has 55,000 miles on it but nearly half of that has been trailer towing so the plugs may well be nearing their end of life and the boots have seen a lot heat. I am going to follow the recommendations of new plugs and boots.

I am also going to check the transmission fluid. Even if it looks good I plan to change the filter and what is in the pan.

Krusty
Nomad
Nomad
It's ignition misfire. Replace your spark plugs and your ignition coil boots. Make sure the spark plug gap is set to the low end of the spec and make sure to put a bit of dielectric grease around the inside of the boot.
Krusty
92 F-250 4x4 460 5spd 4.10LS Prodigy
97 Rustler RT190
EU2000i
Garmin

Grit_dog
Nomad III
Nomad III
theoldwizard1 wrote:
Check the color and smell of the transmission fluid. It should be bright cherry red and not smell. Either of those are bad !


But before you freak out, trans fluid "smells" even when new, but it should not smell burnt.
Also, bright cherry red is more an indicator of a recent service and if you have 50k or 100k on trans fluid, (and not all atf is red, but most is) it may be brownish and still functioning properly. (May be time to change it, for sure, but it's not a certainty that it's bad, or causing an issue)
It's just like motor oil or gear oil. It picks up contaminants and those contaminants darken the oil. The red color is also dye, so back to my previous statement. Bright red only tells you it's not that old. It's not an actual sign of transmission health unless you're monitoring it right after a fluid change, which a pan drop and refill which most typically do, only gets about half the fluid.
Some "red" atfs turn color relatively quickly. One of the best fluids on the market looks nasty after not that many miles (Castrol Transynd), but works spectacularly.

In short, if it aint burnt, it aint the problem!
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

BenK
Explorer
Explorer
Agree with others, think a misfire

As a min, suggest tuneup with new plugs & wires/ignition modules (all of them)

Assuming you were also running 91 octane

Also, have you flushed your coolant yet? 2016 so 6 years and is the coolant is at end of life.

Turbo creates tremendous amounts of heat. More so at full boost. With such a small block/heads, the surface area to reject that big block amount of air/fuel requires very good heat rejection system to get those higher BTU's per square inch surface area out

Ask the others who know more about boosted small engines if dropping down one plug heat range for towing heavy & into high boost a lot would help...but maybe down side would be non-towing, would the plug then foul more easily ?
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theoldwizard1
Explorer
Explorer
Check the color and smell of the transmission fluid. It should be bright cherry red and not smell. Either of those are bad !

carringb
Explorer
Explorer
Misfire? What's the mileage on the spark-plugs?
2000 Ford E450 V10 VAN! 450,000+ miles
2014 ORV really big trailer
2015 Ford Focus ST

blofgren
Explorer
Explorer
alexleblanc wrote:
check to make sure your tires haven't rotated on the wheels. I had this happen to me two years ago with a new set of tires and the spin on the bead, felt just like you described.


Wow, that's a new one for me! What did you end up doing to correct the problem?
2013 Ram 3500 Megacab DRW Laramie 4x4, 6.7L Cummins, G56, 3.73, Maximum Steel, black lthr, B&W RVK3670 hitch, Retrax, Linex, and a bunch of options incl. cargo camera
2008 Corsair Excella Platinum 34.5 CKTS fifth wheel with winter package & disc brakes

Grit_dog
Nomad III
Nomad III
Could be transmission related, however it sounds like it could also be a misfire.
I've had a similar condition/symptom on an older Ford (2011) and again with my new silverado.
Feels like you hit a small bump or pothole initially, but with the Ford, it ended up being a couple bad ignition coil packs. The Chebbie had lifter issues.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

Grit_dog
Nomad III
Nomad III
alexleblanc wrote:
check to make sure your tires haven't rotated on the wheels. I had this happen to me two years ago with a new set of tires and the spin on the bead, felt just like you described.


You physically felt it? That's crazy! I've had/seen tires slip on the bead, but never imagined it could be that pronounced.
2016 Ram 2500, MotorOps.ca EFIlive tuned, 5” turbo back, 6" lift on 37s
2017 Heartland Torque T29 - Sold.
Couple of Arctic Fox TCs - Sold

alexleblanc
Explorer
Explorer
check to make sure your tires haven't rotated on the wheels. I had this happen to me two years ago with a new set of tires and the spin on the bead, felt just like you described.
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