3rd gear knock (Solved)

Kevin - Illinois

Kevin - Illinois

Senior Member
For those of you who were following my thread on the 3rd gear knock, I replaced the rear end with a used one and the knock is gone. Here again is a video of the knock when I had it. It was in 3rd only, and it went away when I let up on the gas, and also when I pushed in on the clutch. At the time it sounded like it was coming from the flywheel area...

http://www.youtube.com/watch?v=VMb7dD9eB_4&feature=youtu.be

I have been in contact with a person to rebuild my old rear end. I am curious what we find and I'll let you all know.
 
Last edited:
Kevin that's great that you finally found it. Hooray!!

I look forward to the final analysis

Thanks for the updates. The real learning comes from follow up reports. The rest is a guessing game.
 
It must have something to do with torque since it was only in 3rd gear. I would never have believed it, but we tried everything else.
 
I am with you Kevin. I would have bet it was something else. Why only third, that is the question. Glad you found it.
 
I also look forward to a report on the condition of the removed rear end. It seems to me there would have been some observation that could have been made that would have pointed in that direction. One we missed doing, or misinterpreted. I'm betting something is going to be visably wrong in the rear. I sure hope so anyway. It will be educational.

I'm relieved for you that you have finally got that behind you. Good move on your part getting that other rear end.
 
As an aside, the "other guy" who had a knock sound only in third gear solved his by replacing with another used rear end. He was convinced that it was the transmission. In his case it was hard to believe as it was a different transmission from when he originally got the car. What are the odds of that? I went over to listen to it after telling him to put the rear axle on jackstands and block the front. I could only hear the knock/noise in third gear. My assumption is the gear noise in first or second masks the knock noise. When in direct drive the transmission is quieter. He's planning on disassembling it in the winter to see what's wrong.
 
Kevin,

Many thanks for the most informative feedback information. So very few are sincere & thankful "real" gentlemen who give their valuable time to provide feed back.

Your wife must be elated -- bless her heart!

Your never giving up is inspirational. I would have thought some experienced Model A person in your Illinois area would have come to offer to help -- but, just a different generation, I guess.

Hopefully you can get this vehicle on the on the road to make your dream & your wife's dream come true.

Please keep us posted.
 
Yes this is a truly bizarre ending, but so glad you figured it out. By all means let us know what you find in that rear end, we are biting our nails...
 
please take some photos or another video of the rear end if you have time thankyou gump
 
I hope to start opening it up this weekend. You can bet there will be pictures and videos...what a learning experience this has been...
 
A number of years ago a car came into the maintenance tent at a MAFCA national with the complaint that there was a knocking noise in the transmission in high gear. They pulled the rear end and transmission and did a complete overhaul of the transmission. I looked at all the parts they replaced and could not see anything wrong with them.

When they got evrything back together the knock was still there. They pulled the rear end a second time, removed the torque tube and found the culprit.

The two large nuts that screw onto the pinion sleeve had come loose. Both nuts, along with the locking tab washer, had walked up the drive shaft and were found at the front end. This allowed the front bearing on the pinion to come loose and allow the drive shaft to move fore and aft some amount. They put the nuts back on and tightened them to acquire some amount of pre-load and the problem was gone. I am sure the ring & pinion was battered, but it all seemed to work.

The two nuts on the pinion sleeve establish the pre-load on the pinion bearings. The first nut actually sets it, the second nut is suposed to lock the first. To do the job properly you need the two Ford factory wrenches. A service bulliten states you should tap on the wrench with a hammer to make sure the second nut is really tight. Too often chisel marks are found on the front nut indicating the nut was tightened with a hammer and a chisel.

Tom Endy
 
A friend had the same thing & was convinced it was the u-joint. I gave him a good used u-joint which he installed & the knock was still there. I went over to his place & jacked up the rear end put it in third gear with the wheels off the ground & with a stethoscope you could hear the noise in the rear end. He swapped the rear end & that fixed it. I don't think he ever checked his old rear end to see where the knock was coming from.
 
Tom Endy said:
A number of years ago a car came into the maintenance tent at a MAFCA national with the complaint that there was a knocking noise in the transmission in high gear. They pulled the rear end and transmission and did a complete overhaul of the transmission. I looked at all the parts they replaced and could not see anything wrong with them.

When they got evrything back together the knock was still there. They pulled the rear end a second time, removed the torque tube and found the culprit.

The two large nuts that screw onto the pinion sleeve had come loose. Both nuts, along with the locking tab washer, had walked up the drive shaft and were found at the front end. This allowed the front bearing on the pinion to come loose and allow the drive shaft to move fore and aft some amount. They put the nuts back on and tightened them to acquire some amount of pre-load and the problem was gone. I am sure the ring & pinion was battered, but it all seemed to work.

The two nuts on the pinion sleeve establish the pre-load on the pinion bearings. The first nut actually sets it, the second nut is suposed to lock the first. To do the job properly you need the two Ford factory wrenches. A service bulliten states you should tap on the wrench with a hammer to make sure the second nut is really tight. Too often chisel marks are found on the front nut indicating the nut was tightened with a hammer and a chisel.

Tom Endy
Click to expand...

Wow Tom, that is educational, and good to put into the memory bank. You are such an amazing resource.
 
Tom I think you may have identified the cause. There is over 1/4" of end play in the drive shaft. I can grab the end of the drive shaft with channel locks with the rear end still together and pull the drive shaft in and out of the torque tube over 1/4". Again I'll brake it down and post pics.
 
Congratulations Kevin, your attitude throughout this whole ordeal has been nothing short of amazing as others have also pointed out. What a learning experience this has been for all of us.
Some things we have learnt are:
1, Don't jump to conclusions.
2, Don't lay the blame on anyone until you discover the problem.
3, Most repairers will work with you if you approach them in the right manner.
4, Always seek advice from others, and be prepared to consider all opinions.
5, If at first you don't suceed, try & try again. Patience will have it's reward.
6, The bigger the battle, the sweeter the victory.
7, Lastly, a noise coming from the drive train may be found anywhere between the timing gear & the differential. The ability of noise travelling through the torquetube cannot be under estimated.

AGAIN A BIG CONGRATULAIONS. We all look forward to receiving our invitation to the celebration party. (So glad you didn't use the Hammer approach)

Runner
 
You must log in or register to reply here.
Back
Top