SWONT2.7
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I am trying to figure out a vibration, or what feels like a vibration in my 2023 F150 2.7 4x4 crew cab 5.5 box, 3.55 rear end. I have been reading the transmission threads for over 3 weeks now I don't think what I am about to describe is transmission related but understand I am not a mechanic. One other thing is that I had the rear blocks (they were square not tapered) removed by the dealer prior to taking delivery. I did not notice any vibrations when I test drove the truck nor did I recall feeling anything for about the first 1000 kms but I didn't use the M mode either. My truck now has 2800 km's (1740 miles) on it. I have two sets of factory rims/tires for my truck, 18s and 20s and I don't believe I have a tire issue since the truck is very smooth up to it's speed limiter. Anyways...
I will do my best to be concise in the description of the problem which I discovered while playing with the "M" manual mode. In 3rd gear at approximately 2800-3000 RPM under heavy to full throttle the truck obviously accelerates and does so very well but in and around 3800-4200 RPM I "sometimes" get a slight shake - it's hard to describe, sometimes I think it's slightly audible and I can always feel it ever so slightly. It is similar to the tires scrambling for traction but I don't believe that is it. Under low to moderate pedal pressure this thing is pure butter - zero complaints.
I have felt this when the transmission downshifts but it is harder to replicate because speed and pedal pressure need to be precise so that the correct RPMs are hit. I can duplicate this rumble sensation (sort of like hitting a rumble strip but much milder) in 4th 5th and 6th with what I would describe as diminishing results. 7th it will do but it is barely noticeable. I have not been able to duplicate the sensation in any of the other gears, higher or lower. If I floor it from a standstill it obviously winds through first gear and then shifts but the RPMs do not fall back very far ( I can't recall but they may fall to 4500-5000) and therefore there is no rumble. It seemingly stays above the normal rumble point of about 4200 rpm. I count myself as lucky because my shifting at full throttle is very quick, very smooth, and overall just fantastic.
It is only under very specific circumstances that I can duplicate the rumble like sensation. I have only run 91 octane. I don't hammer it until it's nice and warm.
Things I ponder: driveshaft improperly balanced. Pinion angle off due to rear block removal which would require shims. Maybe the combustion chamber does not like full throttle at those RPMs under that type of load (therefore possible "normal"). I have had numerous automatic and manual transmission vehicles over the years and I know what lugging is. This resembles that very slightly and maybe that is what is actually happening. I have a 100lb stall mat in my bed (don't think this has anything to do with it). As well I thought maybe a bad plug or coil but I think I would be experiencing issues most of the time, correct me if I'm wrong.
I believe if I had a bad driveshaft I would feel this in every gear and would feel it most, if not all, of the time. If I had unbalanced tires then I would feel this at most highway speeds from 40mph all the way to 100mph but I don't. I don't have any other akward sounds or shimmies or vibrations, it's very specific.
I will hook a trailer to it next week to see if this is exacerbated under load as I have not done this yet. I tow a 4000lb boat and 1500lbs of gear/kids during the summer. I have not been to the dealer, that will unfortunately be my next move to see if this might be a programming issue.
Wondering if anyone has any knowleadge regarding this or maybe has felt something similar?
Thanks for listening.
I will do my best to be concise in the description of the problem which I discovered while playing with the "M" manual mode. In 3rd gear at approximately 2800-3000 RPM under heavy to full throttle the truck obviously accelerates and does so very well but in and around 3800-4200 RPM I "sometimes" get a slight shake - it's hard to describe, sometimes I think it's slightly audible and I can always feel it ever so slightly. It is similar to the tires scrambling for traction but I don't believe that is it. Under low to moderate pedal pressure this thing is pure butter - zero complaints.
I have felt this when the transmission downshifts but it is harder to replicate because speed and pedal pressure need to be precise so that the correct RPMs are hit. I can duplicate this rumble sensation (sort of like hitting a rumble strip but much milder) in 4th 5th and 6th with what I would describe as diminishing results. 7th it will do but it is barely noticeable. I have not been able to duplicate the sensation in any of the other gears, higher or lower. If I floor it from a standstill it obviously winds through first gear and then shifts but the RPMs do not fall back very far ( I can't recall but they may fall to 4500-5000) and therefore there is no rumble. It seemingly stays above the normal rumble point of about 4200 rpm. I count myself as lucky because my shifting at full throttle is very quick, very smooth, and overall just fantastic.
It is only under very specific circumstances that I can duplicate the rumble like sensation. I have only run 91 octane. I don't hammer it until it's nice and warm.
Things I ponder: driveshaft improperly balanced. Pinion angle off due to rear block removal which would require shims. Maybe the combustion chamber does not like full throttle at those RPMs under that type of load (therefore possible "normal"). I have had numerous automatic and manual transmission vehicles over the years and I know what lugging is. This resembles that very slightly and maybe that is what is actually happening. I have a 100lb stall mat in my bed (don't think this has anything to do with it). As well I thought maybe a bad plug or coil but I think I would be experiencing issues most of the time, correct me if I'm wrong.
I believe if I had a bad driveshaft I would feel this in every gear and would feel it most, if not all, of the time. If I had unbalanced tires then I would feel this at most highway speeds from 40mph all the way to 100mph but I don't. I don't have any other akward sounds or shimmies or vibrations, it's very specific.
I will hook a trailer to it next week to see if this is exacerbated under load as I have not done this yet. I tow a 4000lb boat and 1500lbs of gear/kids during the summer. I have not been to the dealer, that will unfortunately be my next move to see if this might be a programming issue.
Wondering if anyone has any knowleadge regarding this or maybe has felt something similar?
Thanks for listening.
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