Well I had my plugs and boots changed a few weeks ago which solved my then misfire problem. The shuttering when shifting out of overdrive went away and all was good. Until today.... Driving the back roads home, my truck usually goes into overdrive and then shifts down out of it when accelerating on a hill or long straightaway. Now instead of feeling a slight shutter, I feel an actual clunk coming from what seems to be somewhere in the drive train. I can't tell if it's another misfire or not, but it definitely feels different this time around. A lot more violent, and "mechanical" if that makes sense. Before I could tell it was a loss of power. Now it feels like an actual clunk. And note it's only when shifting out of overdrive. All the other shifts feel fine.

What do I do? I've put so much money into this truck, mainly in mods, that I can't afford to keep doing it. It's going to be a 10 year old truck, it's paid off, yet problems are occurring more often now. Last time I had it to Ford they couldn't even diagnose the misfire for me, I had to figure that out on my own. So do I at the very least take it to them to diagnose this problem? Or do I start looking for a new truck? Just very frustrated and depressed at the moment...

 

Anyone?

 

There's a fairly common issue with the slip yoke grease causing a clunk. Basically, you need to add some more grease to the slip yoke. Look that up and see if it matches your symptoms.

 

^^^^+1

I had the same issue and greasing the slip yoke solved it. My clunk occurred when going down hill and the tension on the drive train would loosen up and then when going back up hill it would clunk. Very easy and cheap maintenance to do.

 

Thanks guys, I'll look into that. The only reason i'm thinking it could be another misfire problem is because it's happening at the same time as it was before, just when it downshifts out of overdrive, and not during any other shift.