Good morning, I'm a new member here but have already spent many hours reading through others forums. Looks like a great place for Ranger owners!

I bought a 2008 Ranger Sport 4x4 with the 4.0L engine this week. It's high mileage (220,000 Kilometers), though its nearly all highway I believe. Owned by a farmer.

I noticed an unusual sound that seems to be coming from the middle-to-back of the truck, and seems to only happen in 2wd. It sounds a bit like a hollow metallic whirr. It starts around 20km/h and gets steadily louder with speed.

It doesn't seem to be affected by engine rpm, as it doesn't change as the truck shifts (it's an automatic trans by the way. Inside the cab it kinda sounds like an air leak coming from the back of the passenger floor.

With the window down, riding along a concrete divider to act as an amplifier, it sounds to me like it's coming from right under the driver-side passenger seat. As I slow down, it becomes less of a whirr and more of a fast click, very similar to the sound of a chain rolling on sprockets, like a chain-drive motorcycle sounds.

When I switch to 4x4, the sound is there for a second, but once I hit the gas it shuts up completely. I might here a faint occasional sound here and there, but nothing like in 2wd.


After climbing under the truck, I see the transfer case is right around where the sound seems to be coming from. I've read that riding 4x4 on concrete can stretch a chain inside the case, could this be what I"m hearing??

Beyond the transfer case, what other things could this be - rear diff? But I'd think it would maintain the noise in 4x4. It really does not sound like it's coming from the front end at all. When I lean over the dash, it's very noticeably quieter than leaning to the back window.


My thought was to drain the transfer case oil and look for metallic particles. If it's all shiny and full of metal, hit the junk yards for a replacement.


This is actually my first 4-wheeled vehicle. I've been a motorcycle and dirt bike guy for many years and am very comfortable doing all my own work, including engine repair, electrical, body, suspension etc. I've worked on a bunch of Honda's, BMWs, Suzuki's, etc...


Any advice is appreciated!!

 

Here's a photo of the truck!

 

old_smokey

Welcome to the forum. My Ranger is my first truck and first Ford. I have learned lots here. I have even tried to fix things on my own. Also been successful at getting it fixed. All other SUV's in the past I just drove. Tinkering is fun.

Ok the sound you hear. This video has a sound in it. This matches what you described. If this isn't it. Could you please post a video of it? I'm super hoping I got the noise.

https://r4---sn-vgqsenek.googlevideo...70A6550B35B112

 

Hello, thanks for sharing that video! Great idea to put a camera down there. My sound is pretty similar to what you hear at the 45 second mark to about 55 seconds, a rapid metallic click that blurs into more of a whirr as you speed up. I haven't heard any clunking sounds like in the video, when shifting into or out of reverse. I would say around the 35km/h point my truck sounds very much like that video.

 

Here is the title from that youtube video.

WHAT A BAD U JOINT SOUNDS AND LOOKS LIKE: "UNDER TRUCK CAM"

For some reason that didn't come with the video. If that matches your sound? The title is you problem.
Hope you can fix it. If not an exact match love to hear what you have.


Jim

 

Oh I didn't see the title, interesting! A u-joint would be quite a bit easier to replace than a transfer case I suspect.

I don't have a go-pro or similar camera, but I'm sure I can borrow one within a couple days. I'll hunt something down and take a video of my own, then share here!

 

Second question - is this camera right near your rear differential, or is it up by the transfer case? I can't quite tell

 

You could always hang onto your phone tight and video it to make sure.

 

Good idea. I haven't had a chance to check it again because my front passenger brake flex hose cracked. Pretty scary having zero brakes that fast! Thankfully it was a real easy fix, did it in maybe an hour or so. Since this truck is new to me, I was going to drop it off at my mechanic to have him do a quick once-over. I'm hoping the sound is audible while on a lift, that'd make this easy to diagnose. I'll report back soon!

 

Took it to my mechanic, up on the lift and it became pretty obvious what it was. It's the u-joint on the front drive shaft. That explains why it went away in 4x4, and why it sounded like it was coming from under my seat.

It's a little weird that when I'm on the highway it sounded more like it came from behind the seat, but who knows, maybe that's just the way the sound reverberated into the cabin or something. Anyway, there is a bunch of slop in the joint, and the transfer case appears to be just fine.

I guess I'll look into rebuilding those joints if I can, I hope someone makes a rebuild kit or something. If not, the entire shaft has to be replaced at some point, Ford wants $750 (Canadian) for it!

Since it's summer, I don't need the 4x4 at all right now. Any harm in just taking that shaft right off but still driving it in 2wd while I work on the u-joints?

 

Figured I'd update this. It was NOT the u-joint like the shop suggested, but the CV joint on the other end of the front drive shaft.

Last night I removed the front shaft and found the little rubber boot had ripped up. I had a huge amount of slop in the CV joint, with a loud CLUNK as I rotated it in my hand.

With the front shaft removed, my truck is nice and quite on the road. So now I've got to source a CV replacement for the shaft. May as well do the u-joint on the other end while I've got it off. I don't need 4x4 till winter anyway so this will be a rainy day weekend project I suppose. Just happy the transfer case is ok!

 

I recently went through this same problem. I did not get the sound but found the rubber boot had disintegrated during a routine inspection and the CV joint was getting loose. There are CV joints available but I don't know the quality of them. I decide to take the front driveshaft to a power train shop to get it fixed. They warned me that many times a guide or something like that which is part of the driveshaft gets worn and they have to rebuild the entire driveshaft. They recommended just buying new driveshaft because rebuilding and balancing is almost as much.

I asked them to take the CV joint end apart for evaluation. Later they called and said it would need a complete rebuilt. I asked them to just put everything in a box and I would pick it up. I was just going to replace the CV joint myself. Unfortunately, they had taken everything apart including removing the balance weights. I eventually found a new driveshaft for a reasonable cost and went that route.

Driving around without the front driveshaft will not hurt anything. I did it for a month including a trip from CA to KS and back and had no problem. In fact, it accelerated better around town with a slight improvement in gas mileage. High speed driving had less vibration also.

 

Interesting, thanks for the tip. I called the local go-to drive shaft shop here and they offered to rebuild the u-joint and balance the shaft for a very reasonable price, but did not offer CV servicing as an option. So I figured I'd price out a CV rebuild kit, then take the shaft for balancing and the u-joint rebuild. Rock Auto has a complete front shaft for $370 Canadian, I'm pretty sure I should be able to rebuild the CV and have it balanced for less than that..