How the T tramsmission works

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Model T Ford Forum: Forum 2014: How the T tramsmission works
Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Thursday, July 03, 2014 - 11:26 pm:

This was posted a while back but thought it was time to repost;
http://www.modeltcentral.com/transmission_animation.html


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Schmidt on Friday, July 04, 2014 - 12:05 am:

I am getting a chatter when I move into high gear.
Engine runs smooth in 1st and reverse. Does the
high gear band need adjusting or replacement?
Thanks, Steve


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Friday, July 04, 2014 - 12:30 am:

There is no high gear band. High is direct drive. Are you getting the chatter while running in high, or just when you shift?


Top of pagePrevious messageNext messageBottom of page Link to this message  By John P Noonan on Friday, July 04, 2014 - 01:02 am:

I have posted about this a few times. I chalked most of it up to just being a new driver and learning how to shift correctly, but no-matter what i do i still get that annoying chatter that vibrates the car until i reach a certain speed, then it seems to die down. I am thinking it is either a failing front u-joint, or my clutches are slipping. I tried adjusting the screws for the fingers to no avail. I did notice that Langs sells a spring shim to boost the pressure on the clutch spring, it looks pretty crude in its design, but i am thinking about trying to make something similar to boost the spring pressure to see if this is in fact the problem. Has anyone else done this with any success?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tim Wrenn on Friday, July 04, 2014 - 09:08 am:

Steve & Steve... I get that chatter too, mostly on my '20, occasionally on the '12, but it's immediately upon "popping" the clutch into high gear. Only lasts a second, maybe from not "de-celerating" enough first? Then it always "shudders" a bit as the car picks up speed, you can see the right front fender especially vibrate a fair amount, then smooths out. Normal?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Schmidt on Friday, July 04, 2014 - 09:26 am:

I am getting a chatter in high gear at lower speed. I have not attempted higher speed until this is resolved. In a previous T that I owned for 20 years, I never had this problem.
Thanks again for any advise.
Steve


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Friday, July 04, 2014 - 09:49 am:

With only two speeds, the step from low to high is huge - it's like shifting from first or second to fifth in one step in a modern car with a manual transmission. The engine has to be strong and run well (check the timer, clean it and oil it if you have a timer that needs oiling) and it may help if you reduce the throttle and retard the timing at the same time you let up the pedal into high, then open up the throttle and advance the timing as the car gains speed.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Friday, July 04, 2014 - 10:53 am:


You need this.

Actually I think John may be onto something. The clutch contains 25 disks that are sandwiched together, alternating big, little, big, little, big, little. The big ones turn with the engine. The little ones turn with the drive shaft and rear wheels. In direct drive the clutch squeezes them together so they have to turn together. The big disks, turned by the engine, turn the little disks and make the wheels go around. When you pull back the lever or step on the low pedal the spring pressure holding the disks together is relieved so the disks aren't squeezed together and the big ones don't turn the little ones. In high (direct drive) if the spring pressure is weak the disks will slip. I think this is sometimes a source of chatter.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Danny Stroh on Sunday, July 06, 2014 - 12:02 pm:

Question from 1st time user of this web board: I am new t Model Ts and need some help!!
I rebuilt a 26 engine and transmission to put int my wife's 1910 T. Used Kevlar bands and new 8 disk modern clutch discs. Has original rear end that has been very noisy.
Half way through 4th of July parade all of a sudden there was nothing in any pedals. No brake, no reverse, no low gear and no high gear. Nothing.
Might this be the infamous thrust washer failure I have read about??


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Sunday, July 06, 2014 - 12:24 pm:

Could be, but since you don't mention any strange noises, I'd rather think it's the key for the pinion gear or the pinion itself that is broken. The keys for the rear wheels doesn't break as commonly, though the axle shafts does - but since your rear wheels stayed in place it's probably not the case.

I'd recommend you to pull the rear end for a full rebuild, soon you'll know what's wrong. Were you able to stop the car with the hand brake?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Derek Kiefer - Mantorville, MN on Sunday, July 06, 2014 - 12:25 pm:

Danny, I'm the guy you spoke to on the phone Thursday morning. From your description, I think that it is thrust-washer failure.

I have an MTFCA axle rebuild book you can borrow... Google says you live 10 miles from me. :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Sunday, July 06, 2014 - 12:27 pm:

Actually, I believe the little ones are turned by the engine and the large ones are connected to the drive shaft through the lugs in the brake drum.

Danny,

Could be, but I would have expected to hear a hellacious ratcheting noise if that were the case. Definitely sounds like something has turned loose between the transmission and the axle. Could be anything from sheared bolts on the back of the brake drum to a busted U joint to a broken drive shaft or axle to a sheared key on the pinion or axle, busted pinion gear..... Could be lots of things. You need to go through it logically and determine what the problem is. If it has babbitt thrust washers, then you need to replace them even if they are not the culprit......This time.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Semprez-Templeton, CA on Sunday, July 06, 2014 - 01:43 pm:

Danny, for certain something has separated your rear end from your engine/transmission. This should be fairly easy to troubleshoot/resolve. You have a lot of brainpower here on the forum to get you through this issue. Please keep us posted.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Sunday, July 06, 2014 - 03:00 pm:

By the way, I see the animation still shows the LOW and REVERSE gears rotating in the same direction when in neutral. They actually rotate in opposite directions when in neutral, hence the need for the LOW band to be pushed to the right to self energize while the REVERSE band has to be pulled to the left to self energize.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Huson, Berthoud, Co. on Sunday, July 06, 2014 - 05:08 pm:

Danny Stroh:

It could have been a dozen things and yes the infamous babbit thrust washers is one. I hope you are not driving that T without going totally through the rear end. When you restore a T you should go through EVERY little aspect of the T. Don't trust any thing in a 114 year old car.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Danny Stroh on Sunday, July 06, 2014 - 05:40 pm:

Thanks all! Just made it home again and the T even stayed in the trailer for the 12 hour trip.... :-)
Will start by pulling rear end apart and tightening the new bands up some more. Will provide some feed back after I see what I find inside.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Barker - Dayton, OH on Thursday, July 10, 2014 - 11:18 am:

Danny - Any update?

Doesn't sound like a band problem, as you lost all three pedals at once. Beware of over-tightening your kevlar bands, as you could cause dragging and overheating the drums, resulting in cracked drums and even more problems than you have now.


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