Rotational drivetrain noise & clunk

[RangerCamp]

Hi, I wonder if anyone has any clues to what might be happening to my truck (96 Ranger 4x4 xcab, auto, electric BW1354). Sometimes, seemingly randomly, usually while accelerating though, suddenly a ratcheting/whirring type sound starts up. Sounds like it is coming from the transmission tunnel, or behind, and is a rotational noise. Almost like a card-in-bicycle-spokes noise. It is tied to the speed of the vehicle - it slows down as I slow down. You can feel a vibration and hear the rhumm-rhumm-rhumm-rhumm, but otherwise it seems to drive fine. Then, once I slow to like 5 mph, there is 1 or 2 loud Thump/Clunks that you can feel thru the floor, and everything is back to normal, usually for many more drives.

Trans was rebuilt 2 years ago but shifts fine, except for a 3-2 downshift clunk that has been there ever since, and others have it too so it seems halfway normal. When the noise started yesterday on the highway, I put the trans in Neutral to see if it would stop, but it Continued. Does this rule out the trans? Could it be the torque converter, something misaligned inside? Output shaft bushing failed? Hanger bearing, t-case output bearing, other bearing failed? Something else? Please post your comments and advice, the noise is quite troubling, but when its not happening, truck drives almost like new. Thanks!!!

 

[DangerRanger]

First thing that comes to mind is a U-joint.....
Good luck.

 

[90rangersuper]

I would bet on u-joints as well, just changed the rear u-joint what a PITA without a press but the truck would clunk whenever i let up on the gas or going from drive to reverse and vice versa
good luck

 

[AllanD]

No, that "rattly" noise is operator malfunction.

Usually operating at too LOW an RPM in a gear other than 1st.

You m8ust understand that engines don't actually rotate smoothly
the crank accelerates and decelerates in parts of a normal rotation.

This is pronounced at lower rpms and the mazda trans which uses
ATF as lubricant doesn't damp out those noises the way a trans
filled with gear oil would.

The noise is best described as a Pseudo-Lugging noise.
I say Pseudo because a true "lugging noise" would have
engine parts slapping around making noises instead of
the transmission "telegraphing" noises in resonance with
rotation inconsistancies.

AD

 

[RangerCamp]

Thanks for the replies. The investigation into the noise is ongoing, it only happens once in a while. However it is seeming more and more likely that the sound is from the right front auto hub trying to engage on its own while in 2wd. I will update once this theory is confirmed, or junked.

 

[Dynaride]

Ok so what did you find was the problem?

Seems that I have a similar issue. Start the truck up put into Drive,
Little thump or two then drives fine.

 

[RangerCamp]

Old thread but figured I would post the result...
Noise was indeed the front pass. side autohub trying to engage. "Card in bicycle spokes" type noise could describe it. Luckily, this time no replacement was needed. Just needed to grease the front end. I have Moog greaseable ball joints and they were dry causing some sort of binding. Pumped them full of grease and haven't had the noise come back. Watch out when you take your vehicle for general maintenance, if you are short on time and can't do it yourself. Don't know if it's due to laziness, or ignorance about the greaseable type of ball joints but these places might claim to lube your chassis but I'd do it myself to make sure they get every fitting.