old transmission gears wont fit on new main shaft

[Tom Bellfoy]

I am at a loss as to what to do now. I am rebuilding a noisy transmission (first, second and reverse gears real bad whining noise) and it wan not popping out of any gear) because of worn teeth on input shaft and bad gears on cluster. I have one set of second and third gears from the noisy transmission and one more set from another transmission that seem to be quite usable. I also have 4 defective main shafts, one from this transmission and three others. With that said I ordered a new main shaft # A-7060 from my very reliable dealer who did state that the new shaft was USA made. Problem is that the second and third gears will not go over the shaft., I did manage to get one larger gear to go on , however it is very tight and I doubt it would slide even with 600 weight oil. My dealer has been helpful to the extent of checking his stock. I am told the new shaft is designed to fit the new gears, nothing said about the old gears being able to fit. So what do I do now, dealer says my measurements are within manufacturers specs. My way of thinking is that Henry made specs so that we wouldnt have to purchase sets of gears, but in this case my 85 year old worn gears wont even go over the shaft. I cant see any burrs on the new shaft or anything to stop the gears from fitting on. Whats my next step ?? Has anybody else has this problem ?

[1930artdeco]

Can you maybe sand down the haft just enough so that they will fit? That is Ali got short of buying the new gears which should all be in spec. anyhow.

Mike

[J Franklin]

In the Ford bulletins the mechanics were instructed to test fit the gears to shaft. I don't remember the page #.

[Tom Wesenberg]

Spur gears make a whine by their design. Is this the whine you are trying to get rid of?
Or, is there some unusual loud noise?
What gear oil are you using?
Do you have a picture of the bad gears?

[Benson]

Do any of the gears that will not fit the new main shaft say "Argentina" on them?

I tried to build a transmission 40 years ago where the gears would not fit a Ford shaft.

The gears would ONLY fit the Made in Argentina shaft, not the Ford shaft.

Turns out they were made in Argentina and were the wrong size. I returned them and bought a set of Mark gears and shafts.

My advise is to replace ALL of the bearings.

Especially the three needle bearings even if they look good.

Do not leave out the spacer between the two bearings inside cluster gear. Leaving it out allows the bearings to move to one end of cluster, allowing up/down movement of cluster shaft/gear and makes noise and wears gears.

[Larry Jenkins]

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Also the cluster gear and the reverse gear shafts. Which now have "O" rings on them to prevent leakage.

Larry

[Rich in Tucson]

A few years ago I bought a set of new gears and shafts, all were from Mark Auto (USA). The sliding gears would not fit the shaft. I spent a few hours stroking the shaft with 400 paper (yes, it was very painful; I probably still have the warts, but I did not name them to differentiate them from the background of warts) however I was able to obtain the sliding fit described by Ford.

The resulting transmission, with all new bearings and in a NOS case, is still very noisy in second after a few thousand miles and has a weird resonance noise in third at certain speeds that probably is due to a bearing. New pilot bearing in flywheel and flywheel and clutch housing dialed in for runouts.

It is very tight and unforgiving in shifting (rebuilt shift tower too) unlike an all-original with old worn gears (I am using Shell Omala 680 gear lube) and I wonder whether the new gears are anything close to originals in regard to dimensions and hardness. Perhaps in a few more thousand miles it will shift easier without the notchiness but I am always collecting good old gears and shafts...

[harleytoprock]

The best way is to have the gear honed to the proper fit with the shaft on a Sunnen hone machine at an auto machine shop.

[Tom Bellfoy]

Tom W. It is not the usual spur gear noise, its almost like a grinding noise in reverse, first and second gears,. third gear was nice and quiet. After I took it all apart I noticed the input shaft and the cluster gears were in a real worn and pitted shape. I was using 600 weight oil. I have trouble getting pictures sized small enough to attach. In my original post I was referring to the two sliding gears on the main shaft and incorrectly named them second and third gears.
J.Franklin - I just referred to the service manual and will get my caliper out to make sure of my measurements. From what I have read using older gears with the new shaft should all fit as long as they are within the min/max tolerance. Unless I'm reading it wrong.

[Tom Wesenberg]

I had a tranny that made a terrible noise in all the gears but high. Every part inside was just like NOS, except the bearing between the input and output shafts. A couple rollers were damaged, (one was flattened) and it's hard to believe the racket that came from such a small damaged part. The shafts were OK, and a new bearing made the tranny like new again.

[Glen in Hillman MI]

I had the same problem several years ago. I was told that there were 3 manufacturers of the shaft. All were American made. I then called another supplier and asked where he got his shaft and ordered theirs. The same problem, the sliders would not go on the shafts. I then called the third supplier and he guaranteed me that his was the right shaft. After trying it and calling him back, his only answer was that I did not have Ford sliders. They were, as far as I could tell, original gears that were put in there at the factory. At that point I was lost on what to do and took them to an old retired machinist to see what he had to say. He measured the shaft, put it in his lathe which had a 1 1/2" belt sander attachment, did a little sanding, remeasured it and handed it to me. The sliders slid right across them with no hang up at all. He said that he took .005 off the shaft.

[mrtexas]

I'll sell you a complete set of good used gears for $50 plus shipping. Paid more than that for one new shaft?

[Mitch//pa]

Originally Posted by mrtexas

I'll sell you a complete set of good used gears for $50 plus shipping. Paid more than that for one new shaft?

Sounds like a no brainer. Nice offer

[Tom Bellfoy]

All the sliding gears I have are not from Argentina, they must be original Ford gears. I brought some sliding gears to an automotive machine shop for their consult, unfortunately they did not have a cylindrical grinder, they suggested that I use some abrasive paste or compound on the shaft, maybe I'll have to buy new sliding gears. I'm surprised I'm about the only one having this problem !!

[Dan Partain]

Page 303 in the Service Bulletins details a change in the main shaft and the sliding gears in size and width of the splines and shaft. Maybe the repro shaft is made to the later spec's and your gears are from before the change preventing them from fitting properly.
-DAN

[Tom Bellfoy]

Glen:
I read the revised specs for the improved fit in the service bulletin (page 303), The maximum diameter of a new shaft is to be 1.2490
This new shaft made by Mark in USA is 1.2500 which makes it out of spec by .001
The spline portion of the old gear is very close to the maximum on all the gears I have in my possession, which almost makes a press fit situation.

[Tom Bellfoy]

update:
Since the Ford Barn info has been very helpful to me over the years I thought I would post the end result for anyone that will encounter this problem;
I was able to reduce the outer diameter of the shaft enough to make a good sliding fit of the gears by putting the shaft in my lathe at slow speed using 400 grit paper with some valve grinding compound. Final finish done with 600 grit. not sure if the compound helped much.