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Discussion starter · #1 · (Edited)
Hey y’all,

I’ve got this strange low speed (between 30-40 mph) vibration/shutter that occurs at low RPM. If I’m passing through an area with low speed limits it’s torture. Especially at 35-40 mph, unless i tap the gas to make it change gears then it goes away. I recently changed all 6 spark plugs and triple checked the gaps, they’re all between .30-.32 and i got rid of the MSD coil packs and put in 6 brand new OEM motor craft coil packs. Now I’m chasing this feeling. Truck has a 4.5” super lift kit, brand new front end, new U-Joints, differentials we’re serviced within the last 8k miles along with the transfer case and the trans drain and full service is coming up soon. The only other issue I’ve found on the truck will be handled soon, i have a leaking vacuum pump, extremely slight leak but I’m planning to handle it asap
 
Discussion starter · #3 ·
@Saddlebrook - have you had any luck resolving this issue? Seems to me to be transmission related?
none at all. i pulled my spark plugs andchecked the gaps. Only one was off by a tad. It went away for a while then returned today. I think I’m going to replace them again. I didn’t have this issue at all until i replaced all of the plugs and coils in november
 
Sounds like you need to figure out if you have a driveline shutter/vibration or a misfire.

you describe the former but seem to be chasing after the latter
 
Sounds like you need to figure out if you have a driveline shutter/vibration or a misfire.

you describe the former but seem to be chasing after the latter
agreed. Did the 4.5” lift include a pinion shim? That much lift is probably enough to cause issues with the pinion angle and that would cause vibrations
 
Discussion starter · #6 · (Edited)
Sounds like you need to figure out if you have a driveline shutter/vibration or a misfire.

you describe the former but seem to be chasing after the latter
I had a bad shutter at one point, but resolved that with brand new U Joints. Now the issue I’m experiencing only happens at 30-40 mph at lower RPM. None of it began until the spark plugs and coils were changed And those were changed because some guys called it about the MSD coils lol. One of them died on me while in Las Vegas, so I decided to change all of it And get rid of the E3 Spark Plugs too. It’s my fault for not clarifying properly in my initial post. The way the shutter feels, especially now that I regapped cylinder one, it feels more like the RPMs may be too low around those speeds. If I manually downshift the truck, everything is smooth again. When I head out tomorrow I’lll be sure to make note of the RPM’s are. I’ve been studying regearing the truck after seeing some who kind of described a similar issue.
 
Discussion starter · #7 ·
agreed. Did the 4.5” lift include a pinion shim? That much lift is probably enough to cause issues with the pinion angle and that would cause vibrations
It did not include a pinion shim, i’ll definitely look into that, but I did replace the U-Joints and that stopped the vibrations. THe only one I have seemed to start right after I replaced the spark plugs with motorcraft and replaced my MSD ignition coils with OEM Motorcraft coils. I did pull up all of my spark plugs except for one, only because I couldn’t access it at the moment due to misplacing an adapter I found yesterday (I’m on the road, cross country from my home base lol). Cylinder 1’s gap was too open, corrected that and the weird shutter stopped for a week. I’m thinking I need to check the gap on the one cylinder I couldn’t access which I’m planning to do tomorrow.

I’ve been doing some research about what RPM’s these vehicles should be in within their power and in each gear….Now I’m starting to wonder if I need to re-gear the truck (its on 35x12.5R20’s) or if I need to tune it or both. It’s strange that it only does the weird shutter between 35-40 at low RPM and at no other time.
 
It did not include a pinion shim, i’ll definitely look into that, but I did replace the U-Joints and that stopped the vibrations. THe only one I have seemed to start right after I replaced the spark plugs with motorcraft and replaced my MSD ignition coils with OEM Motorcraft coils. I did pull up all of my spark plugs except for one, only because I couldn’t access it at the moment due to misplacing an adapter I found yesterday (I’m on the road, cross country from my home base lol). Cylinder 1’s gap was too open, corrected that and the weird shutter stopped for a week. I’m thinking I need to check the gap on the one cylinder I couldn’t access which I’m planning to do tomorrow.

I’ve been doing some research about what RPM’s these vehicles should be in within their power and in each gear….Now I’m starting to wonder if I need to re-gear the truck (its on 35x12.5R20’s) or if I need to tune it or both. It’s strange that it only does the weird shutter between 35-40 at low RPM and at no other time.
I would not want to add a tune or make any other changes, such as re-gearing until i tracked this down… so are you now running all motorcraft plugs and coils? Still experiencing a “shutter?”
 
Discussion starter · #10 ·
I would not want to add a tune or make any other changes, such as re-gearing until i tracked this down… so are you now running all motorcraft plugs and coils? Still experiencing a “shutter?”
Everything is motorcraft. I’m working my way back down south from California. Going to get to my brothers shop and properly diagnose it.
 
It did not include a pinion shim, i’ll definitely look into that, but I did replace the U-Joints and that stopped the vibrations. THe only one I have seemed to start right after I replaced the spark plugs with motorcraft and replaced my MSD ignition coils with OEM Motorcraft coils. I did pull up all of my spark plugs except for one, only because I couldn’t access it at the moment due to misplacing an adapter I found yesterday (I’m on the road, cross country from my home base lol). Cylinder 1’s gap was too open, corrected that and the weird shutter stopped for a week. I’m thinking I need to check the gap on the one cylinder I couldn’t access which I’m planning to do tomorrow. I’ve been doing some research about what RPM’s these vehicles should be in within their power and in each gear….Now I’m starting to wonder if I need to re-gear the truck (its on 35x12.5R20’s) or if I need to tune it or both. It’s strange that it only does the weird shutter between 35-40 at low RPM and at no other time.

Dont feel alone in your quest regarding the shudder you're dealing with. I just bought my F150 with the genII 3.5L ecoboost TT XLT 4x4. Its not lifted and has the stock all weather tires still mounted. I came across your post because I was researching the exact same issue today online. It seems to me that it is due to what you had mentioned in one of your latest posts. I too believe it to be a shift position @ too low of an rpm. I noticed my transmission shift position to be in 6th and 7th gear @30-40 mph when it starts the shuddering.
It quickly fades away however, as soon as you accelerate out of that range. It also does not shudder at all when you continuously accelerate from any speed <30 through >45 mph. Which, in my opinion is pointing to tranny shift point programming.
 
Welcome to the forum.
And right on too!

It might not be true for all 10r80 transmission shudders, but there's a big percentage of them that would provide a much more refined experience if the CAFE driven default shifting strategy wasn't so aggressively aimed at low RPM shifting.

If driving at a normal pace, but using the so called Sport shift strategy yields less shudder/NVH, then you can pretty much point to the issue.
 
Dont feel alone in your quest regarding the shudder you're dealing with. I just bought my F150 with the genII 3.5L ecoboost TT XLT 4x4. Its not lifted and has the stock all weather tires still mounted. I came across your post because I was researching the exact same issue today online. It seems to me that it is due to what you had mentioned in one of your latest posts. I too believe it to be a shift position @ too low of an rpm. I noticed my transmission shift position to be in 6th and 7th gear @30-40 mph when it starts the shuddering.
It quickly fades away however, as soon as you accelerate out of that range. It also does not shudder at all when you continuously accelerate from any speed <30 through >45 mph. Which, in my opinion is pointing to tranny shift point programming.
Lead frame?
Is that an issue with the 10spd?
 
Nope.
But there's a few potential issues that are a bigger problem than the 6R80 Leadframe is. (in my opinion)
 
No, not lead frame. Shift strategy for fuel economy.
 
Discussion starter · #16 ·
Dont feel alone in your quest regarding the shudder you're dealing with. I just bought my F150 with the genII 3.5L ecoboost TT XLT 4x4. Its not lifted and has the stock all weather tires still mounted. I came across your post because I was researching the exact same issue today online. It seems to me that it is due to what you had mentioned in one of your latest posts. I too believe it to be a shift position @ too low of an rpm. I noticed my transmission shift position to be in 6th and 7th gear @30-40 mph when it starts the shuddering.
It quickly fades away however, as soon as you accelerate out of that range. It also does not shudder at all when you continuously accelerate from any speed <30 through >45 mph. Which, in my opinion is pointing to tranny shift point programming.
I just saw this, but I believe youre correct. I had to change the transmission lines due to a trans line failure that thankfully happened in the parking lot at my friends shop. The shudder is almost non-existent now. Truck has its trans flushed every 30-40k miles. Swapped to a much bigger transmission cooler,all new lines. I’m actually getting the truck tuned soon and the tuner agrees about the programming.
 
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