Hey, Scotty. Love your videos and your solutions.
I bought my pickup with 230k miles on it last summer. It was a cosmetic nightmare, but it ran like a new one. Still does now with 238k. But there's a clunking feeling somewhere underneath when I stop and go. I thought I had a loose rear axle, but the mechanic who raised it and gave it a glance said there was nothing loose that he could find--not shocks, not ball joints, not the bed, and so far as he could tell, not the u-joints.
I'm wondering if maybe motor mounts or transmission mounts could cause this. I was told when I bought the truck that the engine had been rebuilt at around 150k. It's tight as a drum, no oil burning or leaks, etc., and I've restored it cosmetically to look like new. I don't want to keep it if there's a costly or dangerous looming problem, but I don't want to give it up if I can get the stinking clunky feeling to go away.
I know the Generation 11 F150 had lots of issues, but I have grown to love this old truck, and I bought it for a song.
Thanks for any advice you might offer. If you say sell it, I will, though it'll break my heart.
Mike in Lubbock
crazy idea: strap an old smartphone under the chassis and record video while driving
I would suspect your third member (rear differential) has a lot of play in it from so many miles. I'll bet the play between the ring and pinion gears is way out of spec and the tooth contact pattern is way off.
Well at ~240k miles on it that clunking sound it likely your transmission going out as I assume its an automatic. If that sounds sync up with the car changing gears you can almost guarantee its the trans. If you desperately want to keep it your going to spend a small fortune getting a replacement transmission installed and don't try rebuilding it unless you can find a absolute PRO that can do it. Otherwise I'd just baby it for as long as you can and your best off finding another truck when the trans finally does go out. BUT get your truck scanned with a dealer level(expensive) scan tool(don't go to a ford dealer tho) to assess the damage. You might be able to drive it for a good while with that clunk before it kicks the bucket. Just baby it till then and don't try towing anything or carrying super heavy loads as that will put even more strain on the trans and cause it to burn out even faster.
Thanks for the input! The clunking doesn't seem to be coming from the motor or transmission--it's more like play in the differential or driveshafts, but the fellow who looked it over said he couldn't find it, and of course you can't hear/feel it will it's not being driven. It only happens from a dead stop when I step on the gas. And it's not bad, just worrisome. Thanks again for the response!