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.

Maybe get the vehicle checked for codes at a repair shop or even autozone or similar. Codes may not show but that might be the 1st thing to check imo.

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.

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.

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.

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?

Drivetrain slipping? | Good Sam Community

Hank85713
Explorer
Feb 17, 2022
Maybe get the vehicle checked for codes at a repair shop or even autozone or similar. Codes may not show but that might be the 1st thing to check imo.
alexleblanc
Explorer
Feb 17, 2022
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.
Grit_dog
Navigator
Feb 17, 2022
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.
Grit_dog
Navigator
Feb 17, 2022
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.
blofgren
Explorer
Feb 18, 2022
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?
carringb
Explorer
Feb 18, 2022
Misfire? What's the mileage on the spark-plugs?
theoldwizard1
Explorer II
Feb 18, 2022
Check the color and smell of the transmission fluid. It should be bright cherry red and not smell. Either of those are bad !
BenK
Explorer
Feb 18, 2022
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 ?
Grit_dog
Navigator
Feb 18, 2022
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!
Krusty
Nomad II
Feb 18, 2022
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.