Clunking / rattling sound in manual transmission

ford
ranger

#1

Hi, folks,

I have a '97 Ranger with about 120k, 5 spd manual transmission, 2wd. For the last 2-3 months I’m hearing and feeling a clunking or rattling noise (I can’t decide which it is) coming from the rear of the vehicle at random times.

I can’t really predict or find a pattern of when the noise will happen, but it seems like it is most likely to happen when I’m either accelerating up a hill or when I’m braking relatively hard. It happens whether the clutch is in or out. Doesn’t seem to matter. It does NOT happen when idling, only when traveling. I don’t ever remember it happening at highway speed (65mph).

If I have my hand on the stick shift I can feel the shaking / rattling as it happens. There seems to be no impact on the performance of the vehicle - no additional trouble shifting into or out of gear, accelerating, or anything else.

On a recent trip I towed a 1,000 lb trailer and I did not feel or hear the noise at all during that trip (about an hour each way).

Any guess as to whats going on? Thanks…


#2

That noise can come a worn U-joint.

To find out , raise the rear of the vehicle so both tires are off the ground. Place the transmission in neutral. Grab one of the rear tires and rotate it back and forth while watching the U-joints. If a U-joint is worn you’ll see the slop in the U-joint.

Tester


#3

Have you checked the fluid level yet? I believe this truck uses ATF, but it is still checked through a fill plug on the side of the case.


#4

Rattling from the back of a pickup truck could be coming from a host of things. I don’t think I’ve ever ridden in a well-used truck that didn’t rattle somewhere. I’m assuming you’ve looked top and bottom, shiny side and greasy side, in the rear for loose fasteners, loose tailgate, jack mounting, spare tire, heat shields, etc. and convinced it is not something like that.

Since the sound is coming from the rear, it seems unlikely the problem is in the transmission or clutch. Something in the drive train further back must be a tad askew. The first thing to do is check to make sure the fluid level in the rear differential is ok, and the fluid doesn’t show signs of water contamination. If it is the same fluid in there since the truck was new, this is a good opportunity to replace it with new.

Next – as mentioned above – is to check all the u-joints from the transmission output to the differential. There should be absolutely no play in any of them. On my Ford truck, what I do is I crawl under there and try to twist the driveshaft with my hands, watching each u-joint one by one. Even a slight amount of play, I’ll replace the offending u-joint. If you notice some play in the differential, this may or may not be a problem; a small amount of differential play is normal.

This is also a good opportunity to lube the u-joints if they have grease fittings.


#5

Thanks, guys! I did not do the thorough inspection that you suggested, mainly because it seemed unlikely to me that it would be something simple like a tailgate or spare tire mount because I’m feeling it in the stick shift. I assumed it was something in the transmission or drive train.

Now that you mention it, I do remember seeing some sort of stain / leak on the differential, so the problem could definitely be there. I’ll ask my mechanic to check that and the u-joints. Thanks!


#6

I recall Ford Rangers using a slip joint in the drive shaft which could wear and cause such noises. Also, the Ranger bell housing could make contact with the pinch weld ridge at the floor/firewall seam if a motor mount is failing.