This has been driving me crazy for months.

I own a '96 Ford Ranger, with a 2.3 four-cylinder and a Mazda M5OD manual transmission.

A few months ago, I started to notice a minute noise coming from the drivetrain, in the vicinity of the flywheel, starter motor, and front of the bellhousing.

The noise was small, and sounded somewhat like a skill saw (like a "tickling" metallic noise). This noise occurred at the top of shift ranges, most noticeably when taking off from a start.

I asked the people I bought it from if the clutch had ever been replaced, and they said no. So, I replaced the pressure plate, clutch plate, throwout bearing, and pilot bearing.

After this, the noise went away for a few days, but then came back with a vengence.

Now, it will make a "violent" rattling noise. It sounds like somebody repeatedly tapping a frame rail with a peening hammer very quickly, depending on driving conditions. It will make this noise when the truck first starts and the idle begins to slow to normal (typically about five seconds after ignition). It will also make the noise at all of the points described above, and also when coasting to a stop.

For the meantime, I've just adjusted my driving style to work around the problem points, but I would like to fix the problem for good so I can continue with this truck's "restoration".

When I changed the clutch, I noticed that the input shaft coming from the transmission had a small amount of play to it... maybe 1/32" of an inch in either direction. I don't know whether this is within specs or not (a search in both my shop manual and online turns up no endplay specifications), but could a worn or damaged input shaft bearing make this type of noise? I don't see how but I've never had to replace one before...

Another possibility I've pondered is an exhaust problem. I've known since I bought the truck that the catalytic converter was going bad. The exhaust sounds plugged, and the converter heats up way above the temperature of other exhaust components while driving (enough to heat up the cab... in fact).

Does anybody else know what this noise could be coming from? I'd like to get this truck back running smoothly, because I plan on commuting a good distance come fall. If I can't narrow this down, I might wind up selling the truck and keeping a Mercury I'm trying to sell at the moment.

Thanks in advance for all the help, and tell me if I left something out.

 

Well I was sorta thinking about a hanging up starter bendix, that wasn't retracting all the way, & tinging on the flywheel teeth, so if you think this is possible, maybe consider pulling the starter & check the bendix to make sure it's moving freely, but your other observations are plasusible too, so seems to me you might have more than one problem & some more trouble shooting to due.

I'm not a tranny guy, but the tranny shaft end play sounds at least questionable to me, so if you don't get any replys on it's specs here, try the tranny forum, bet someone there knows what the specs are.

Is the tranny lube level up to snuff & are the rubber plugs not weeping, or leaking & are sealing ok????

Is the tranny tail shaft mount ok, not worn or loose????

The cat converter over heating problem needs to be addressed pronto imo.
Could be a clogged exhaust as you suspect, or maybe an up stream engine fuel trim problem.

So is the engine running hot & do you have a CEL lit????

If so, have the computer scanned for trouble codes & post All of the code Numbers, as they could provide good trouble shooting clues????

If you don't have a code reader or scan tool, most autoparts stores will scan the computer at no cost if the CEL is on.

You could also do a clogged exhaust system check with your vacuum gauge. You'll have dropping intake manafold vacuum as you raise the rpm if the exhaust is restricted, just follow the gauge instructions for the test.

More thoughts for ponderng, let us know what you find.

 

From your description I would really suspect the heat shield loose on the cat. I had one that did the same thing. I just went to the local hardware store and got a couple of worm gear clamps that would fit around the cat and put them around it and tightened it up. The noise went away and has not returned.

 

Hey all. Just got off of work.

The starter, you say? I can easily take a look at that on my off days, and a simple fix to boot (trip to the salvage yard...).

The CEL was not lit and the computer threw no codes when I got the truck. While replacing the transmission, I crushed a fusible link (or some other connector... not too good with electronics) going to the pre-cat oxygen sensor with the bellhousing while lining it up with a transmission jack. The light came on during my test drive, so I'm sure that's the cause and code to throw, but I will of course check this over the weekend. Engine doesn't run hot (the temperature gauge is one of two gauges that work on my instrument cluster... a future fix ) either.

The transmission received flying colors when I had it out to replace the clutch. All rubber plugs were in good condition (not cracked, supple, and not faded/worn), old fluid was at the correct level when I drained it, and I checked the level about a week after changing the clutch (was perfect). The mounts were in great condition as well.

I'll definitely check the heat shield when the exhaust cools down sometime over the weekend (fixing to have to drive to our old house to move a dryer in for the tennants, so it'll be hot for the rest of the night). I'd have to buy a vacuum gauge and tachometer to do the backpressure test, so I'll probably just have that done if nothing else pans out. I have a source for a new catalytic converter for around $125 (installed and everything... good to have friends...), so I might just get the guy to run that test also.

Thanks for the replies. I'd rather get this truck running right, because I'm waiting to make sure it's nothing serious/expensive (like a new transmission or input shaft bearing) before fixing all the other things needing work. Basically, I need a.) new tires, b.) a title notarized and taxes paid, c.) a power steering sensor, d.) floor covering (bare metal ATM), etc., etc. I guess I got what I paid for, though. Definitely not a vehicle to take your date into the city with, though. I'll borrow a friend's car for the time being.

 

No need to buy a vacuum gauge, as most autoparts stores have them in their "Loan-A-Tool" program, for a refundable deposit.

If the exhaust or cat converter is restricted, it's not doing the engine, or your oil any favors.

Is it glowing red hot after a drive, or highway run????

When you put your hand over the exhaust pipe, does the exhaust pressure feel weak????
Does the engine lay down on acceleration, or feel weak at high rpm highway cruise????

 

The cat doesn't glow even after long drives (I've crawled under and checked several times).

The exhaust sounds very weak, and also feels quite weak. As for engine performance, it does feel "weak" when cruising, though I don't seem to have many problems with acceleration (although I do a lot of city driving). Entrance ramps usually put me on the interstate at around 60-65.

 

If this noise happens only when the manual transmission is engaged, it's likely that input shaft.

If you have your hand on the shifter when you hear this noise, does it vibrate along with the noise you are hearing.

I have a 5-speed Mustang that does this. The synchros in the transmission work fine, but in the high RPM ranges the transmission rattles bad. Even at an idle the shifter rattles too much.