So this might end up sounding like more of a rant, because it is. I went on a random drive on a cold-ish day the other day and experienced some abnormal clunking, exactly like the clunk you hear when the slip yoke is bone dry and binding up in the transmission, which I'm very familiar with on past trucks. Is Ford still shipping trucks with bone dry slip yokes after literal decades of this being an issue? Searching the forum suggests that it is. I had this issue on my 02 and 05 F150s, I would have never dreamed that I would STILL have to address this on my 2020.

Just angrily ordered the Motorcraft PTFE grease on Amazon. I'm the biggest Ford fan around but this is just silly.

 

Could you describe the clunk and the characteristics of what you’re doing when it occurs? I have a driveline clunk and I’m trying to determine if it’s slip yoke or u-joints. Is there a difference in the two clunks these two parts will cause?

 

It's tricky because there are so many clunk sources with the 10 speed and this driveline. In my experience with bad u-joints, they violently and CONSISTENTLY clunk at low speed coming to a stop and when taking off. Slip yoke is more inconsistent based on what the suspension is doing and if it's been bound up enough to snap loose. I haven't read much about u-joints going bad early on this platform, so unless you have a ton of miles, it's likely not that.

Keep in mind that the transmission can also clunk in certain scenarios, like when it's freewheeling between 30-40mph and you get back on the gas. Ford considers this "normal."

 

Is it like a popping noise or clunk?

 

I understand your angst and have not heard of Ford shipping these dry before your post. When my 13 did this, I performed the procedure at 40K and it has not come back, its been 105K miles since I did it. Truck now at 145K, I used the blue Ford stuff.

 

I gotcha, from that description it may be more on the slip yoke then. My clunk is pretty inconsistent, doesn't happen on stop or take off, but it seems to only happen when I take my foot off the gas when accelerating around the 35-45 mph. It's like stopping the acceleration surge makes it clunk - but it doesn't happen when braking, taking off, etc. I do have a little over 100K miles though. Transmission recently rebuilt, and the clunk was happening before and after that, so I don't believe it'd have to do with that.

 

I think they do put grease on it but its a very thin film of grease they use.

 

Here’s my 2020. Looks like I have the slip yoke clunk. 40k miles. Super frustrating.




i notice it happens when the tranny flexes some when I take off. Almost like it’s causing a bind. Might have the dealer double check the motor and tranny mounts when I take it in.

 

are you not in the powertrain warranty still? I’m gonna take mine to the dealer.

 

I know the fix, so in the interest of time I’d rather spend $10 on the PTFE grease and 10 minutes in my driveway rather than the inconvenience of a dealer visit. It’s just unfortunate that Ford doesn’t address these issues that have persisted for many years.