39 Ford transmission noise

M

Mike/NY

Member
My restored 39 Ford transmission is noisy at all speeds, there is a whine when it gets warm, similar to 1st gear. The car is an early 39 Ford, so it has the 1938 style transmission and shifter. ****** was rebuilt so that worn or damaged gears were replaced with good used correct parts and ****** was rebuilt using new shafts, bearings, thrust washers and gaskets. Works fine but whines at all speeds, at 65 the whine is almost unbearable. I am using 80W90 mineral oil. Our other 39 Ford with an original untouched (late) ****** is quiet on 2nd and 3rd as it should (same oil). What could be causing the noise? It has only been driven about 300 miles so far. Thanks.
 
Maybe mixing and matching used gears from different transmissions has given you some undesirable gear mesh conditions. Also, some of these so called 'new' bearings available today are no where near the quality level of the original bearings used back in the day. I built a '39 transmission for one of my projects and chose not to use some of the new bearings that came with a rebuild kit. I'm sure they would have caused problems if I had used them.
Mac VanPelt's transmission book and some phone calls to Mac were a huge help to me during my trans. rebuild.
 
If the early type transmission has any straight cut gears, it will have some normal audible gear whine except in high. High is direct drive through the two shafts so the counter shaft is unloaded and shouldn't make much noise. Rear axle noise can travel up the torque tube and sound like it's comming from a different place depending on what the problem is sometimes.
 
I would rather use an original Ford bearing if it is in good shape than a new Chinese part...... Just saying
 
I would run it with the rear wheels off the ground and make sure the noise is coming from the transmission. It could be the rear end after it warms up.
Butch
 
I was also going to say it may be the rear end. I drained and filled the rear in my early ford and it got a lot quieter. I had thought the trans was the culprit.... That was until I replaced the trans with another and it still made the same noise.
 
Rear end? Good point. It does seem strange that the transmission would be noisy on high gear. When the car is cold there is not really that much whine and the whine gets louder when the car gets warm and especially at high speeds. I was thinking of replacing the ****** but will need check the rear end first starting with the oli. Thanks for your comments. Mike
 
I'd be starting with the upper driveshaft bearing. Drop the speedo turtle and check the color or consistency of the lube around the speed gear, if that bearing is going bad it will sing at high speeds and will be evidenced by a gray silver lube or grease color.
 
Add some Molykote M Gear Oil Additive, 10% by volume to fresh gear oil and then drain and refill your transmission with the new oil/M mix.
Available from many industrial distributors like Applied, Kaman and Motion Industries.
Drive for several hours.
 
The noise does go away when I put the car in neutral at 65 mph and the cars rolls without the noise.

I engage high gear and the noise is back. This is why I though it would be the ******.

What does this mean, would the rear end continue making the noise even on neutral? What about drive shaft.
 
Doesn´t the rear end and drive shaft continue turning at the same speed when the car rolls on neutral at 65 mph and the noise should not go away?
 
Clicking the trans into neutral is a good way to help isolate issues, if the trans in gear makes noise and out of gear makes no noise, this usually indicates it a load related issue, like a bearing going bad.

The next problem is to isolate the bearing first without taking everything apart. A good way to check is a heat check, with the trans cold, take your car for a quick short cruise and then carefully check the temp of the trans case bottom with your hand to detect areas that are warmer than others, check the U joint cap and the upper drive shaft bearing by the speedo turtle also. If the case is warm at the rear potentially its the rear main drive bearing, if the U joint cap is warm it relates to the Ujoint, etc. In any case you should not have a loud whine noise.
 
There's no load on the rear end in neutral. Try playing with the gas, load the rear end under power and compression and also try to cruise it with no load and see what th noise does. I had a bad pinion bearing that only made noise under compression load.
Butch
 
Whatever is making the noise may not do it when freewheeling without a load on the gears. I wonder if the noise would stop if you were driving in third gear and pushed the clutch peddle in all the way to the floor?
 
I would try what Rocketsled suggested in both the trans and rear. I use some molly grease which thickens the oil and provides the molly lubricant. The gears will mix it like a blender. I have been running this mixture for over 30 years in multible vehicles in temperatures down to 45 degrees. Some vehicles had had noise before the mixture and now run quiet. Years ago I made the mixture in a container to the consistancy of thin honey but was a pain to install and latter let the gears mix it. G.M.
 
OK, I should try molly grease, maybe thicker 140W lube and I will also try feeling the heat after a short drive. I guess lifting the car up and running it while someone listens from below is a good idea. As I recall when I press the clutch the noise does not go away, only when I put it to neutral but I need to recheck.

If I need to take the rear end apart I guess I should renew all bearings? Rear wheel bearings are new but rear axle bearings were not swapped. Which all bearings should I swap, where should I buy them and how do I change the bearing in the middle of the drive shaft?
 
If you start off in 1st,windup in 2nd and 3th and see if the noise gets higher thur the gears.You could also put 2nd under power and let off and see if it sounds like rearend.Do this when hot.trans noise is mostly in 1st and 2nd.
 
When it is singing really loud can you change the noise by slightly moving the shifter handle? I am wondering about shift fork noise?
 
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