Hello, 2023 F350 SRW 7.3 10R140 with 2500 miles. This has been happening since almost day one. After backing out of the driveway or a parking spot and more prominently when truck is cold, I'm getting one or two mild "clunks" as I'm letting off of the brake and the truck begins to roll. They seem to be coming from forward of the cab. I have had the wheels off and checked for loose bolts on the calipers and various suspension links with no luck. Once the truck is up to temp sometimes it doesn't happen at all. Once rolling it runs and shifts smooth as butter and this seems to exclusively happen from reverse to drive. I am reluctant to take it back to the dealer because my last experience there was less than ideal. I just figured I would put it up here for y'alls ideas and recommendations. I have searched for similar symptoms but most were transmission related as it up and down shifts and I am having no issues there. This is happening within just a few feet of the truck beginning to roll and, unless it's just in my head, it seems like I can almost feel it in the brake pedal as I am releasing it. Any input would be greatly appreciated.

 

How much backlash is in your rear gear set?

 

1/8 of an inch or so if measured where the yoke enters the differential case. I'm not sure what that would be in degrees. What is odd is that the noise(s) I am hearing don't happen until after I release the brake and they seem to be at or forward of the cab although I know that can be deceiving.

 

I know this sounds basic, but I have seen it.
Have someone (or you) watch the front axle U-Joints when backing up. They should not be moving, unless you have the hub(s) locked in. I have seen where the hub lock was in Auto but it was stuck locked.

Just a thought and easy diag !

ZooDad

 

Thanks! I am able to turn the center front driveshaft by hand in park and watch both u-joints at the front hubs turn freely.

 

It could be the automatic hill parking brakes releasing when cold they could be sticky

not sure the technical name. Brakes go on to avoid rolling while shifting when parked at a slight hill angle

 

Hadn't thought of that, this is usually experienced on flat ground though. Daily when I leave the house and again when I am returning home from work.

 

In my experience, you need to grease the drive shaft yoke that goes into the transmission (it slides in/out). Be careful of the transmission seal when you slide it back in. Ford recommends the white teflon paste they sell. Any good moly paste is OK from my point of view.

 

Thanks! That sure cant hurt anything. If it clears up after this I'll chime back in and let you know.

 

I have the same truck, mine does this as well… about 7k miles on mine, always been clunky.

 

This clunk has been around for a very long time which some Super Duty's and it seems F150's can have it. The cure 99% of the time is just greasing the slip yoke.

 

I will certainly try this and thanks for the input. Do you have a recommendation for a specific grease? Would I be greasing the outside portion of the yoke that slips through the seal on the transfer case and the internal splined portion as well?

 

The internal splines of the slip yoke. This is what ford makes.

 

I wouldn't go out and buy any special grease if you already have some sort of lithium grease that should be good enough. Get a needle nose adapter for a grease gun and pump it into the splines.

 

Awesome, thanks for the pic, I'll get some on the way.