Transmission triple gear pin broke

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Model T Ford Forum: Forum 2015: Transmission triple gear pin broke
Top of pagePrevious messageNext messageBottom of page Link to this message  By Keith Keller on Thursday, July 30, 2015 - 03:03 pm:

Any thoughts on this appreciated. My 1922 T would not go into neutral, tried EVERYTHING. Took the inspection cover off and noticed one of the triple gears is wedged between the flywheel and the slow speed drum and almost next to the next triple gear. 100% sure that the triple gear pin broke. Trans was rebuilt by me last year and new pins were installed. Followed the T manual to a T (I shouldn't be laughing right now I should be crying) Have had no problems until this. Anyone heard of this before and what might be a possible reason other than a weak pin?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Charlie B actually in Toms River N.J. on Thursday, July 30, 2015 - 03:19 pm:

Did it shear or pull out? The result is the same but just wondering.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Keith Keller on Thursday, July 30, 2015 - 03:41 pm:

The trans is sill together and still in the car so I am not sure. I cannot see it. The gear that broke loose is wedged so tight between the flywheel and the drum I am going to have to disassemble the trans to get it out. I had a machine shop remove and replace the pins. Has anyone had them come out on them?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jack Putnam, Bluffton, Ohio on Thursday, July 30, 2015 - 04:01 pm:

I have seen this problem with a customers transmission. The pin came out. You will need to replace the flywheel if your pin did indeed come out. The pins have to be pressed in and out from the back side (magnet side). Pressing them through the flywheel will enlarge the hole and new pins will not be tight enough. If the triple gear is not damaged it can be reused.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Keith Gumbinger, Kenosha, WI on Thursday, July 30, 2015 - 04:01 pm:

Keith - I've broken 2 triple gear pins. They were installed by a "professional" Antique engine rebuilder who now doesn't do T engines anymore.

I think mine broke due to insufficient clearance between the pin and bushing. Neither of mine wedged in like yours - both times my engine still turned over freely and still ran.

I recommend that you have a known and respected T engine rebuilder install new pins and make sure the pin to bushing clearance is correct. There should also be an oil groove in the ID of the triple gear bushing - some bushings don't come with this groove I understand.

There have been lots of posts on this Forum on this topic in the past. Do a search for: triple gear pins, MTFCA.

Keith (Ya, that makes 4 of us named Keith on the Forum I think)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Georgetown TX on Thursday, July 30, 2015 - 04:50 pm:

Probably had the bushing clearance too tight, bushing seized on the pin then the pin rotated until it was so loose it fell out.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Donnie Brown North Central Arkansas on Thursday, July 30, 2015 - 06:54 pm:

correct me if Im wrong. Are the replacement pins supposed to be oversize in the area they press thru the flywheel. I remember reading somewhere that there were .003 oversize pins used for replacements. The pins were standard size in the area of the triple gear and oversize in the press fit area. ????


Top of pagePrevious messageNext messageBottom of page Link to this message  By Donnie Brown North Central Arkansas on Thursday, July 30, 2015 - 07:06 pm:

I remembered where I read it. It is in the Service Manual. Does anyone know if the replacement pins are made correctly .???

1

(Message edited by dobro1956 on July 30, 2015)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Chaffin......Corona, CA on Thursday, July 30, 2015 - 07:17 pm:

Likely the pin broke due to the triple gear bushing to pin fit being to tight. Many a conversation has been had regarding this issue. Let the games begin! :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Frank van Ekeren (Australia) on Thursday, July 30, 2015 - 07:41 pm:

Donnie,
answer to you question is yes, the only issue I find with the new pins is they are a little rough in finish, I polish them up in the lathe before sizing the bush to fit'
Although I've only seen one pin break and did what Keith describes, I've come across several that have locked on the pin and started to spin the bush in the triple gear.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Keith Keller on Thursday, July 30, 2015 - 11:14 pm:

When I rebuilt the tranny, I did replace all the bushings throughout the trans. I do recall after fitting the gears and drums, spinning the the whole unit to make sure the gears/bushings were spinning smooth and freely. As far as an oil groove, I don't know if the gears had it or not. Where would the groove be located? Just looking at the gear as it sets, the teeth have some scoring and grooves on the teeth that are visible. I have replacement spare ones and wold like to know how to identify the oil groove (is it in the bushing?). I am not able to get into this project (nor looking forward too) right away but will post what I find and hopefully no other damage.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Keith Gumbinger, Kenosha, WI on Friday, July 31, 2015 - 11:54 am:

Keith - Yes, the oil groove should be on the inside of the bushing. This is a critical area, and too little lubrication and / or too little clearance between the bushing and the pin can result in the bushing seizing on the pin. Then the pin can shear off, or the bushing might spin inside the triple gears.

Keith Gumbinger


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Friday, July 31, 2015 - 11:56 am:

The oil groove is a double spiral in the inside bore of the triple gear bushing. Be sure the oil groove exits the bushing at each end.



This bushing stuck and spun in the triple gear due to incorrect install, the face of the bushing must be done per the Ford Manual, paragraph 292, for having a projection over the gear of .006"-.010". This bushing face was too thick, and galled on the flywheel, locking the bushing.

Triple gear pins, made for after service, Part # T-751AR, are made with a straight end for the flywheel holes per Ford spec, to fit the bore of an original flywheel where the original factory pin was removed. Hopefully vendor parts are make to print, so easy to get the correct dimensions from the Ford prints! Best to mike each part prior to pressing.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Pat Kelly Montana on Friday, July 31, 2015 - 03:20 pm:

Since were talking triple gears, can someone explain why you have to time the gears and what happens if you don't? PK


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Dufault on Friday, July 31, 2015 - 03:52 pm:

http://www.mtfca.com/discus/messages/118802/162733.html?1285802179

and

http://www.mtfca.com/discus/messages/257047/315760.html?1349917734


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Hatch on Friday, July 31, 2015 - 04:04 pm:

I have found the repro pins are not polished fine enough. I have to polish each one to get them to work. Dan


Top of pagePrevious messageNext messageBottom of page Link to this message  By Pat Kelly Montana on Friday, July 31, 2015 - 07:44 pm:

Thanks Dave, PK.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Kevin Holland, Utah on Friday, July 31, 2015 - 08:33 pm:

After rebushing the transmission I found the existing pins fit just right. I bought the new pins but did not like the fit of the gears on them, so I did not use them. So far; so far.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Les Schubert on Friday, July 31, 2015 - 09:37 pm:

Kevin
My experience has been the opposite of yours. I generally have found that I replace the pins and run the old Ford bushings and get a good fit


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Lovejoy, So Cal on Saturday, August 01, 2015 - 12:37 am:

I just got done doing mine, first time. One flywheel I looked at had a hole for the triple gear all worn oblong, looks like it had come out at some time. I did mine as per the book best I could - we well see. But this makes me nervous :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill Howell on Saturday, August 01, 2015 - 09:35 am:

Take a look at the first 10-15 min. of this video.

http://modelt-tips.com/Engine/17.html


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