Noisy transmission ????

[billybronco1]

Yes, I just purchased a stethoscope but need to wait for my buddy before I crawl under the car while running in gear. My concern again is why only in third gear do I hear the noise? Seems to me it would point to something in the tranny but I will poke around and see what I hear later today.

[Tom Wesenberg]

The thing is the tranny has the least things moving while in third gear. Actually the only thing not moving in third gear, vs. first and second, is the bearing between the input and output shafts. The tranny whine coming from first and second spur gears probably overpowers the rear end noise.

[tbirdtbird]

There was a lengthy thread on here about a yr ago about a guy with something similar IIRC. The guy went round and round. I even think he sent his motor back to Skokie thinking it was a motor problem. I do not recall the outcome. It took many pages of posts before we finally had a resolution. I do not recall the final outcome, but he was running his car up on jack stands like you also trying to isolate the noise.

Maybe other posters remember this better. I will try to search for it later

[billybronco1]

Originally Posted by Tom Wesenberg

The thing is the tranny has the least things moving while in third gear. Actually the only thing not moving in third gear, vs. first and second, is the bearing between the input and output shafts. The tranny whine coming from first and second spur gears probably overpowers the rear end noise.

So the thing is then I should hear the noise in all gears if one off those end bearings was bad I would think.

Now keep in mind even with the left wheel turning and the right wheel not it seems the noise is coming from the right - I will know better later.

[tbirdtbird]

OK, found it.

http://www.fordbarn.com/forum/showth...ht=jack+stands

Same symptoms you are having. 3rd gear only. Poor guy had a devil of a time figuring it out. There was an earlier thread that was extensive which I did not link to where he even sent his motor back to the builder

ended up being a chewed up pinion gear. Nice video. Some helpful admonitions from Tom Endy, also, for all of us to remember.....like when you go over railroad tracks be sure to slow up and take your foot off the gas. Evidently the pinion is inherently a weak link in the chain

keep us posted

BTW sometimes there is no accounting for the location of a noise or the gear at which you hear it. Not everything in automotive mechanics is as it seems (that would be too easy). Won't bore you with a recent lengthy story of a SBC having symptoms of a collapsed lifter that ended up being a bad carb. Good thing we were insistent on a proper diagnosis and didn't rip off the intake and change the lifters

Haven't tried this but if you drained the pumpkin, might be able to get an inspection scope inside either thru the fill plug hole or a mounting bolt hole for the axle tube flange on the right side and look at the gears. You won't see anything but the back side of the ring gear if you try this on the left side.

Maybe someone with a rear end out and dry could try this to see if this would work

good luck

[billybronco1]

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Thanks so much that is great information. Now he defiantly had more of a thumping which sound which would make sense after seeing that pinion gear, Mine is more of a roar like a bad bearing. I did put my stethoscope on the shifter inside the car and went threw the gears you can hear it in all gears but it is most prominent in third. Noise is defiantly coming from right rear - more details to come.

[Big hammer]

From post #43 it was (knock in third gear)turn out to be rear end
pinion nuts loose Was a good thread and I followed it He put a loaner
rear end in until his could be rebuilt ( Knock in Third Gear) thread is
what got me interested in ford barn! I have seen any threads after his
rebuilt rear end reinstalled

[billybronco1]

Okay update - pulled the floor and started probing from there. It seems the transmission is quiet but as soon as you go back further on the universal joint cover it gets loud and on the drive shaft cover all the way back to the differential. From the center out to the wheels on both sides as you go out further it gets quieter. The noise sounds loudest by ear on the right side and it does not mater if the right or left wheel is turning.

So with all this said where do I begin? All I have is a floor jack, do I need to take the rear end out of the car? I do not have a spring spreader or any special tools.

[tbirdtbird]

before you rip into everything try my inspection scope idea....some call them 'bore' scopes

If you do need to remove the rear end and rebuild it, have you done anything like this before? It is not for the faint of heart and requires a reasonable amount of mechanical experience. You will need a spring spreader, access to a press, etc. Is there a local club?

[billybronco1]

Where do I find the scope you mention?
I have rebuilt engines before but never dealt with something like this?
Is there a way to pull it apart with out removing it from the car at least open it up to inspect?

[Colonel Biggs]

Get yourself a $10 stethoscope from NAPA. With the rear end elevated and the engine running and the trans in third gear, start at the trans and work your way back to the front of the banjo. If it's the pinion bearings, the noise will be significant all up and down the torque tube. Both the u-joint and trans housings will be quiet, though.

If it's the differential, this is a major undertaking, but not impossible, depending on your level of skill and tools available. Download Tom Endy's 2014 re-write of the procedure from the Santa Anitaas web site (santaanitaas.org) - technical articles. I did one this past summer.

The Colonel

[Cool Hand Lurker]

You can get a borescope on ebay for about $15 that will do the job. Just do a search for "endoscope" and a lot of them will come up. They will hook up to your laptop computer and a disc is furnished to set up the program. Cheap and easy.

[tbirdtbird]

I am not totally sure the borescope idea will work. I am hoping someone like Tom Endy who might have a dry unit on a bench might be able to try this before this guy shells out the bucks for a scope.

The rear end must be dropped from the car in order to do anything to it.

If Tom's article intimidates you it would be better to find someone who has done this before even if you have to trailer it somewhere. There is too much at stake in terms of the cost of renewing the internal parts; and the safety issues of working with the rear spring, which can easily kill you or maim you.

[John S]

Originally Posted by tbirdtbird

I am not totally sure the borescope idea will work. The rear end must be dropped from the car in order to do anything to it.

If Tom's article intimidates you it would be better to find someone who has done this before even if you have to trailer it somewhere. There is too much at stake in terms of the cost of renewing the internal parts; and the safety issues of working with the rear spring, which can easily kill you or maim you.

Good advice here. A rear axle rebuild is not easy or cheap. And if you make a mistake in set-up you can trash 4-5 hundred dollars in parts pretty quick.

[billybronco1]

Well I thanks you for all your advise, it is disappointing to know this is such a major undertaking. I must say I have looked at lots of pictures and read up and the total overhaul project is beyond my level of expertise. Did you all read my #48 post where I probed with the stethoscope? I would only want to replace the one bad bearing if I was doing this myself and I think it the left bearing just on the right of the differential gears. Oh well I guess I will take the car off the road for now an tuck it in the corner or the barn until I can figure this out. I did contact my local chapter of MARCOM to see if someone would like to help out. Perhaps I will join the club and see if I can get a volunteer. otherwise the beautiful car will sit. Can someone send my a picture of a full length spring compressor so I can keep my eyes open for one, thanks

[billybronco1]

Maybe I will just buy this if this is all I need $70 at Snyders, at least I can get the rear end out of the car. Do I need anything else will this work?

[Ron Lachniet]

I know it still sounds silly, but I would take the tailpipe clamp off the frame and run it and see if it changes. In high gear mine was so loud it was hard to talk over and if I let up on the gas it went away. I would never have believed it myself. I fixed the clamp and it is very quiet now.

[Tom Wesenberg]

That spreader is what you need, and you can always resell it after you're done using it, if you don't ever plan to use it again.

[billybronco1]

Originally Posted by Ron Lachniet

I know it still sounds silly, but I would take the tailpipe clamp off the frame and run it and see if it changes. In high gear mine was so loud it was hard to talk over and if I let up on the gas it went away. I would never have believed it myself. I fixed the clamp and it is very quiet now.

I took your advise and disconnected the tail pipe and I can see how that would cause noise and I plan to insulate that clamp to frame hookup later but it did not change my noise - thanks for the tip.

[billybronco1]

Seems there's more to the spreader I think this is the one I need from Mikes $79