I did not have any vibration at highway speeds - and lubing the slip joint likely will not have any effect such vibrations. Most likely culprit for that would be an imbalanced tire or driveshaft angles that are wonky / out of spec. There are lots of other threads on this forum about highway vibrations.
I don’t get a thud as I come to a stop, but I do occasionally get a light thud in the transmission when letting off the gas at a speed like 45mph. It’s not hateful. You think that lubing the slip joint would help with that, or you think it’s an entirely different issue?
Maybe, it's the same kind of forward shifting motion. I would relube it regardless just because of how dry it was and use aftermarket lube not the motorcraft. It's a easy job. I ordered a new boot but it wasn't necessary. All that's needed besides the lube is new clamps for the boot.
CS Moly still going strong here after 10 months. Super smooth drive line. The truck has been in 90-100+ F temps all summer.
I might be wrong, but have always been told not to jack up rear using the bottom of the pumpkin. Please someone correct me if this is bad info.Here is my story relating to the bump on acceleration from a stop...
I bought the truck 3 months ago used, it was a certified used car from a reputable dealership. It was a good deal, 94k miles for 20k. Slowly but surely I noticed a light thump or bump when stopping or accelerating from a stop. It developed to the serious thud. over time and I was nearing 100k miles so I reluctantly (this is a work truck so missing it cost me money) took it to the dealership. I knew something was wrong.
In typical fashion they kept it for two weeks. Then proclaimed they could not reproduce the issues and all they did was perform a transmission re-learn with forscan... >.>
Well, I knew I would have to figure it out myself. I knew 100% it was coming from the rear end. So I went ahead and drained the differential fluid to check for metal shavings and inspect the condition of the fluid. I used a borescope in the fill hole to inspect the condition of the gears inside. Gears and fluid looked fine, nothing out of the ordinary there.
This eventually led me to this forum, and eventually to this thread. Thank you so much for sharing this fix. It is VERY easy if you have the right tools. Here is a picture of everything I used. I did not use a torque wrench, just set the impact to #2 setting and used the German method of gutten-tight.
Honestly this was easier than changing the oil. Seriously. I did not set the parking brake because I just used an impact, the secret here is using a wobble extension to be able to use it. Also I did not have an ear clamp tool/clamps but if you get a CV kit from Amazon the small bands are perfect.
Amazon ear band kit.
https://www.amazon.com/dp/B09NDD3TNQ?ref=ppx_yo2ov_dt_b_fed_asin_title
I could not get the blue Ford official grease soon enough and it was nowhere to be found locally so I got some of this.
https://www.amazon.com/gp/product/B00JF2LBQ6/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&th=1
Bump/thump SOLVED.
Here is everything I needed for the job. Took less than an hour.
**** Tip for getting the splines correct, once you pull out the shaft you will notice a single valley in between splines is all black instead of blue, you'll notice on the female part that there is a couple of spots that have space for two splines, you'll notice it when you take it out even though this may sound confusing.****
