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Puzzled Mechanic

My son bought a 98 Mitsubishi Eclipse 5 speed manual non turbo that started making a whining/grinding/rubbing noise coming from the engine area. I took it to two mechanics who both initially thought it was a throw out bearing. I went with the cheaper mechanic and once he got it torn apart he said the bearing was fine and he thought it was the transmission. He put in a used tranny and still had the noise. He has been working with a tranny shop and they are certain it is coming from the tranny area. He put in a third used tranny and same thing. Is it possible to have 3 bad used tranny’s? The mechanic is very reputable and he says he does not know what else to do. His next option is to take the tranny off and just have the bell housinng on and start the car to see if the noise is there. shold I have him try this or go to another shop? It makes the noise in nuetral idling, clutch or no clutch, and for a short time going down the road. It goes away after a few minutes. Anyone have any ideas?

Before suspecting the transmission they should have considered (and inspected) things on the engine like idler or tensioner pulley bearings, water pump, air compressor clutch bearing, etc.
Noise can echo from one part to another and I would have used a mechanic’s stethoscope to check all of this out before even thinking of removing the transmission.

While anything is possible, the odds of having the same problem on a number of transmissions is near zero.
I certainly don’t understand some of their repair methods.

I don’t understand their repair methods either. I still think you have a bad throw-out bearing. I’ve seen bad ones that looked like new but were very noisy. I think you should find another mechanic and just hope that he or she knows what they are doing. Good luck.

He said they did use a mechanic’s stethoscope and it is coming from the transmission. Could those issues resonate to the transmission area even while listening to it with a scope?

A horrible thought here, but is it possible that what you have is an exhaust system shield rattle (a very common problem on many cars and easily repaired) and all of this has been for naught? This can vary in intensity, come and go, etc. and is more of an irritant than anything else.

Maybe someone should wrap a rag around their fist and smack the header pipe and converter a few times to see if a rattle exists…
If so, ouch.

Its worth a try. I will have him try anything at this point. I would be surprised thought because the sound is more like something rotating together and rubbing and grinding than a rattle.

The thing is that sometimes a head shield noise can easily, very easily, come across as a grinding sound due to it having such a high pitched resonance.

I have a noisy input shaft bearing in my 87 Ranger.Idling in neutral with clutch out & it’s noisy.
Shove the clutch in and it’s quiet.

Is the noise on the Mits the same with clutch in & out?

The mechanic is saying that the noise goes away when the clutch is depressed. Before I took it in, it was making the noise while idling (no clutch)and seemed to be worse on cold days. What about the idea of taking the tranny off and starting the engine with just the bell housing attached? Would that isolated a noisy input shaft bearing or do you think when the tranny is attached it puts enough pressure on something to make the noise?

Since it’s only noisy with the clutch out it does seem to be a trans problem. But 3 bad transmissions?? Hard to figure

How bad is the noise?? I wonder if it’s just the nature of this particular trans.

Odds are that other Eclipse owners have had the same problem, so you might want to post this question on a mits owners forum.

The noise is pretty bad. I can hear it when driving behind in another car. It was doing it for about 2 weeks before we took it in and it seemed to be getting worse. At first it only did it when the car first started going down the road, then it started when the car was first started and warming up.

I may try a Mitsubishi forum.

In your original post you state the noise is present, clutch or not clutch.
Now you’re saying the noise goes away when the clutch is depressed.
Which is it?

And if this related to a throwout bearing or pilot bearing this begs the question of why someone would not recommend installing a new clutch kit while the transmission is out along with a new pilot bearing.

If this noise can be heard while following in another car then it should be plenty noticeable when checking mainshaft operation by hand; if the problem is inside the transmission. I find it impossible to believe a truckload of transmissions would all have the same problem.

The problem was isolated to the transmission yesterday by starting the car without the transmission and no noise. The mechanic did put in a new clutch kit, new throw out bearing and new input bearing during the process. The noise would go away when the clutch was depressed.

After much research I found the eclipse is notorious for bad transmissions. ( The transmissions we bought were warranteed and the mechanic is covering all of the labor so I can’t complain too much. I guess that is what I get for buying a foreign car.

Thank you all for your help. You definately gave out some good ideas.