Rear End Noise

[dans1232]

I have been hearing a noise coming from my rear end while driving. It's a clunking noise and occurs when I hit large bumps and when the truck sways a lot (uneven ground, sharp turns). I started noticing it when I was towing, and now it occurs with everyday driving. It sounds like it is coming from the passenger side rear.

I have tried the following: Replacing the shocks, removing the rear sway bar, inspecting the brakes. The leaf spring looks likes it is in good shape. There are no visible cracks. The U-Bolts all look intact and not moved. I can find any rub marks anywhere.

Can anyone help before I pull what little hair I have left out?

 

[ncranchero]

Have a Reese hitch? I went through a complete inspection of under truck items last week because of a new "clunk". Then I figured out it was the insert in the hitch.......duh! If not that check out the tailgate.

 

[dans1232]

I do have a Reese hitch, but I only put the insert in when I tow. I just inspected the whole hitch assembly and it is secure. I lubed the tail gate when the noise first started happening. The exhaust system is secure. The tonneau cover rattles, but the sound I am hearing is more of a popping sound of something snapping in and out of place.

While under there, I noticed the fuel tank only has one strap going across it in the center of the tank. Is there supposed to be more?

Its a 2001 Sport Trac with 110k, fully stock.

 

[ncranchero]

Yeah, it only has one strap.

 

[Clusterpup]

Heh, is that gas tank made out of metal or plastic. I was curious the other day while under there removing my drive shaft and was banging on it and couldnt figure what it was.

 

[ncranchero]

Steel I think I remember. It may have a plastic shield on it though. My F150 4x4 did.

 

[dans1232]

Update

I talked to a mechanic friend yesterday. He was asking me about recent maintenance and I told him about the rear pinion seal that was replaced in December. He suggested changing the differential fluid. When pulling off the plate, I noticed there was no gasket. The the fluid looked contaminated like water had been getting in. Luckily, I didn't notice any metal shavings. Could this have been a cause? When the gasket seal dries, I'm going to give it a test drive.

My gas tank is metal. It almost looks aluminum or stainless.

 

[ncranchero]

Very difficult to make others understand what you're hearing. I don't have any more ideas. Was the fluid milky, which indicates water? No metal shavings is a good sign though. You can get gaskets to go back on even though Ford just says use RTV. I put a gasket back when I had the cover off of my F150.

 

[cruser761]

sounds likes chips of steel in your differntial case. You can pull this off yourself and check but will need to replace fluide. very common with ford. Shop can do it for free but if you don't want to do it, then take to shop. Their trans and diffs are poor alloy from the third world. It's expensive to have a diff kit. Looking at $1,500 to $2,300. Same with trans rebuild. get ready.