3rd gear noise

[CallmeBob]

I've got a 41 Mercury coupe, motor and trans was rebuilt a little over two years ago, drove several times with no problems. Today I went for a drive it shifted good through 1st and 2nd gears with no noise, but when I shifted into 3rd it instantly started making a noise like a whine with a light rattle mixed in. It don't matter how fast or slow I'm going, if I have clutch pushed or not the sound is still there. When I put it back in 1st or 2nd the sound goes away. Can anyone tell me what may cause this, and a easy way to fix it without pulling the trans.

[KiWinUS]

I’m sure you know this but 3rd gear is direct drive. I don’t know what the issue is but feel for sure it will need to come out. Driving it may possibly damage it further. I’m sure you will get some crystal ball readers that will tell you what your problem is. Good luck.

[hueyhoolihan]

if the pitch of the noise does not vary regardless of speed, then i would think it may not have anything to do with the transmission. but might have something to do with the shift linkage. ...possibly interfering with something in the torque tube or driveshaft depending on what you've got.

umm... your neighbors haven't mentioned anything about their cat missing have they?

[CallmeBob]

No ones said anything about any cats missing. It is a torque tube. The noise does speed up and slow down with speed.

[CallmeBob]

I need to sell it as soon as I get it fixed to help pay medical bills.

[hueyhoolihan]

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Originally Posted by CallmeBob

No ones said anything about any cats missing. It is a torque tube. The noise does speed up and slow down with speed.

good to hear that the hypothetical cat was just that...hypothetical. and if the sound varies with speed my suspicions about something other than the transmission being the source of the noise are much less likely. i was hoping for the best, i guess. good luck.

[Ken/Alabama]

This was my issue with the transmission in my 40.

[petehoovie]

Originally Posted by Ken/Alabama

This was my issue with the transmission in my 40.

[Mac VP]

A proper diagnosis would require a thorough tear down of the transmission. If I had to make a guess, I would also suspect the roller bearings. The last 15-20 years of these that have been available as new reproduction parts have proven to be defective. The assembly techniques and the heat treating are the culprits…….these repro roller bearings may last for a little bit but usually within 500 to 1000 miles they come apart, as shown in the photo above. I wish the offshore manufacturer would make the necessary improvements. However, as long as the various USA vendors continue to buy them there is no incentive to make any changes. As much as we would love to install some shiny new bearings, or sell them for customer parts orders, we refuse to do so.

I have strong opinions about some of the reproduction and aftermarket parts sold in the hobby, but this issue has always been the number one problem to me. I’ll step down from the soapbox now…..

[Terry,OH]

noise with the clutch pushed or not could be the throwout bearing riding on the pressure plate fingers.

[CallmeBob]

The sound is only in 3rd gear, if it was the throw out bearing the sound would be in all gears, I assume. My hearing is not very good so I got my neighbor to listen. He said the whine is not very load, but the rattle sounds like when you run a powered drain snake down a drain and it's hitting on the sides of the pipe.

[GB SISSON]

Originally Posted by CallmeBob

The sound is only in 3rd gear, if it was the throw out bearing the sound would be in all gears, I assume. My hearing is not very good so I got my neighbor to listen. He said the whine is not very load, but the rattle sounds like when you run a powered drain snake down a drain and it's hitting on the sides of the pipe.

The last sentence coupled with the photo in post#8 makes a very good argument for sourcing NOS or NORS bearings, no matter how hard they are to find. And this applies to far more parts than just bearings.

[Kurt in NJ]

have you checked the oil levels in the transmission and rear axle.
Rear axle problems become more evident with speed and may not make noise in lower gears.

[hueyhoolihan]

i'm still hoping it has something to do with something outside of the gearbox. although the fact that it only happens in 3rd gear could be actually something that happens due to reaching a specific speed and not 3rd gear. meaning it could be in the torque tube, differential or even in an axle.

[ford38v8]

Originally Posted by KiWinUS

I’m sure you know this but 3rd gear is direct drive. I don’t know what the issue is but feel for sure it will need to come out. Driving it may possibly damage it further. I’m sure you will get some crystal ball readers that will tell you what your problem is. Good luck.

Good call. They walk among us.

[CallmeBob]

It happens no mater what the speed. With the clutch push in it makes the sound all the way to a stop, so speed has nothing to do with it. I have not tried shifting into 3rd at a lower speed, maybe I should do that.

[pistonbroke]

I'm with Mac. In third gear the lower luster is free floating, with no presure or load on it s it can rattle around and whine due to a slight misalignment until you load it it by shifting to first or second. Tim

[Bored&Stroked]

Originally Posted by Ken/Alabama

This was my issue with the transmission in my 40.

My bet is that you had aftermarket cluster roller bearings . . . they are junk. I only use original Ford stuff (even used) - they don't fall apart like the repop ones.

[KiWinUS]

Have you drained the oil to see what comes out?

[CallmeBob]

I think I figured it out. I when for a short drive today after adjusting the linkage and still had the sound. Went past the neighbors house and he call and said he didn't hear the sound when I went by, but I could still hear it in the car. I also noticed my speedometer was jumping all around so I disconnected it at the transmission and the sound went away. So I'm thinking I have a bad speedometer cable. By the way I got the transmission kit from Dennis Carpenter.