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Newish truck owner here hoping to get a little help. I bought a 96 f-150, 300 I6, manual 4x4 with around 320k kms on it. Ive had a rather uncomfortable development at high speeds. I usually shift into 5th around 80-90kph and for the first months it worked fine. However recently when I shift into 5th now I feel severe vibrations like I'm running on a flat almost, this goes away after a minute or 2 and if I dip back down into 80-90 range it does not appear. I've taken 4th up to 100-110 and there's nothing the same.
I also have a sheer metal scraping/screeching noise only at highway speeds, my exhaust is gone past the cat. I have seen threads saying it could be the heat shield around the cat making that noise but I'm also curious if it could be related.
I just did a trans fluid change less than 1000km ago and I didn't see any large chunks in the fluid or on the plug only a buildup of small flakes and filings.
Would anyone know why I'm experiencing this? Ive never had anything like it before and I'm kinda stumped.
Did the vibration come on suddenly or did it develop over a few weeks ?
First thoughts:
Tires out of balance or different diameter tires on the truck. Could be setting up a harmonic vibration.
U joints... Need to verify you don't have a bad one developing.
Front end wear / Death Wobble
Did the vibration come on suddenly or did it develop over a few weeks ?
First thoughts:
Tires out of balance or different diameter tires on the truck. Could be setting up a harmonic vibration.
U joints... Need to verify you don't have a bad one developing.
Front end wear / Death Wobble
It came on pretty suddenly, about a week or 2 ago. I feel it most in the foot well like it's under my right leg, I haven't been using the 4x4 but maybe it's the ujoint for the front drive shaft.
Is there a way I can verify if a ujoint is bad without moving? I know what they sound like and I've seen videos of them sticking but obviously that's when it's moving.
It could be a balance issue my tires are the same size. My steering wheel is out of alignment too, although I'm not sure how that would effect it.
You say this only happens in 5th gear. Same speeds in 4th gear and no vibration, only vibration when in 5th. Is that correct? If it was wheel balance, u-joints, or some other chassis thing, then it should not be related to what gear the trans is in, only vehicle speed. Always good to check and service the u-joints.
Aside from my original description over the last week the problem had progressed to 4th as well around 85kph.
I was able to get under it today and try the FWD u-joint and that is DEFINITELY the issue. It has a lot of play and moves freely. Gonna get that fixed and it should be good as new.
You have all been helpful so thank you so much for your time and expertise!