At what mileage does your slip yoke start needing greased? I was driving home from work the other day and noticed a very loud thud or clunk under the truck. It was coming from the middle-back of the truck at least that's what it sounds like. To me it feels almost as if something slips and then regains traction. So far I've only noticed it while accelerating through right turns at low speeds which is very odd to me. What should I look for? Could this be a slip yoke? Something suspension related? What do I need to look for?

 

In my experience, mine would clunk on take off (only) when the yoke needed grease. I don't think there's a recommended mileage to start greasing them. But, I would check your u-joints, particularly the joint by the differential. I also recommend pulling the shaft all the way out to properly check the joint. I've had them play tricks on me, and feel good until it's out of the vehicle.

BTW, Ford put a teflon coating on the slip yoke, and when that wears down, it causes a clunk. They suggest using a PTFE grease on the inside (splined) part of the yoke.


EDIT: Here is the EXACT stuff they suggest:

 

Well we changed the transfer case fluid, tried to remove the drive shaft but the bolts in the rear were stuck pretty good. I was going to take a chance driving it to the shop, but backing out it made a different grinding noise so I let it coast back down and let them tow it. The tow driver thinks it's a pinion bearing, or bearing if some sort. It was squeaking pretty good when the pulled it up on the truck but I couldn't get it to make the other noises. I guess we'll just wait and see. Worst case scenario I'll need a new rear end and I'll fab up some way to throw a super duty rear end in it.

 

If your not doing a Sas, don't bother with a super duty axle they are a lot wider than your lifted front. If I recall you have a 4.6? Just pick up a 9.75. It's almost equivalent strength wise to a d60. I'm going to a semi floating 10.25 that was used in the 7700's.

 

You have been having no luck lately.

 

No luck whatsoever.. Blew a plug that turned into a bad lash adjuster, weird noise in the rear end awaiting the verdict on what that could be. I've been contemplating whether or not to sell it. There's no point in having a truck that is in the shop more than you drive it.

 

You have to learn grasshopper.

 

Super duty rear end, SAS, transfer case drop kit or extended drive shaft, full motor rebuild..problems eliminated? With my luck, the rear end would go out, front axle would just fall off, transfer case kit would literally drop the transfer case while driving down the road, drive shaft snap, and the motor rebuild kit would be one for a 4.6 mustang. I'm thinking more and more about selling her and just getting a 7.3.

 

Understandable. I've pretty much decided that anything short of totaling my truck, it's going to get fixed. I just paid off our Escape, and it feels great having 4 paid off vehicles, and not having a car payment.

 

The thing is, I used a credit card to buy the tires so I'm paying on those, and I got a loan against the title to pay for the lift and wheels. Although it wasn't the full amount of the truck, I'm still paying on it.. So on top of the repairs each month, I also have the truck payment, credit card payment and gas at 7 mpg, oil changes every three months, insurance.. I'm literally working to keep my vehicle running so I can get to work. I either don't work, don't have as many break downs, and feel like a bum, or I work, pay for my truck, and that's all the money I have. If I didn't live with my parents I don't know what I'd do.