2000 Ranger Thud/Vibration

[ironman86]

Hello everyone. I just purchased my first Ford Ranger. It's a 2000, 4x4, automatic, 4.0L with 106k. The truck runs fine, but I have one question/problem that I can't seem to find the answer to.

It's starts off like this... I'm at a complete stop, then when I start to accelerate from a dead stop I can feel like a thud like I was just hit from behind by another car. It's a single vibration that I feel through the entire truck. Then when I'm coming to a stop, it does the same thing, thud.

The best way I can describe it is like there is a large heavy ball rolling around in the bed of the truck and when I start to accelerate the ball rolls backward and hits the tailgate, that's the thud, then when I brake the ball rolls forward and hits the cab, that's the other thud.

The dealership I bought the truck from said it was the yoke. They said they replaced and/or lubricated it, but the sensation is still there.

Please post or e-mail me with any suggestions or ideas as to what the problem could be. Thank you all.

Erik

 

[snake]

The stealership was right. Those slip yokes were notorious for that exact problem. But if the yoke is worn out, no amount of lubrication is going to fix it. At one time there was a TSB on it, they would fix the yoke by replacing the entire driveshaft- I forget the price tho, maybe the customer had to pay half or something? I would put the pressure on the stealership to fix it properly and see if the TSB will still cover part or all of the cost.

edit- they didn't replace the shaft but merely lubricated it. Look underneath and I'll bet you won't see a new shaft under there.

 

[ironman86]

The dealership said I needed to wait a few days so the lubrication could work itself over the area. Because before I left with the truck they told me it still made the thud/vibration, but that it would go away over a few days of the lubrication setting in. Is that BS?

 

[ironman86]

What is a "slip" yoke and how is it different from a standered yoke?

 

[snake]

Yeah that sounded like BS to me too...

I haven't really played around with too many 4X4's, but my understanding is the slip yoke is an inner splined section of driveshaft that slips into an outer section and it allows movement of the suspension without binding up the driveline. The splines eventually run dry and are subjected to excessive wear. Lubricating it once it begins to make noise is like putting lipstick on a pig. Within weeks it will fall apart like a three dollar suitcase.

 

[ironman86]

The dealership replaced the slip-yoke and, for the most part, the thud is gone. I do not feel the thud when braking, however, there is a light thud on acceleration still.

I guess this truck proves to be a mystery in the making...

 

[snake]

Interesting. I would check the transmission, T-case, and motor mounts and maybe the front u-joints. See if it does it locked in 4wd, if it does not I'd say the problem is still in the rear (of the transfer case) driveline.

 

[Earl43P]

The dealership replaced the slip-yoke and, for the most part, the thud is gone. I do not feel the thud when braking, however, there is a light thud on acceleration still.

I guess this truck proves to be a mystery in the making...

What you just described is desirable, normal slip-yoke operation.