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The Model T transmission is unlike any other. When you are cruising in high gear (direct drive) the whole transmission is spinning along with the engine crankshaft, flywheel, and drive shaft. In effect it's just a linkage between the engine and the drive shaft. When you step on the low and reverse pedals, magic happens. The low pedal contracts the low band, which grabs the low drum and stops it from spinning. That forces the triple gears to turn, and they turn the drive train in low gear. The reverse pedal contracts the reverse band, which grabs the reverse drum and stops it from spinning. That forces the triple gears to turn, and they turn the drive train in reverse. The brake pedal contracts the brake band, which grabs the brake drum, which is attached to the output shaft so that it stops the drive shaft from turning. Of course that stops the wheels from turning. All three bands — reverse, low, and brake — are lined with a material that prevents the metal of the band from damaging the metal of the drum. Your Model T came from the factory with cotton linings in its transmission bands. In the past century some other materials have been used for band linings. In recent years the available linings have been cotton, wood, and Kevlar. That last material is a modern synthetic fiber. When used for woven band linings it has the advantage of being more durable than cotton and wood.

Is there a downside to Kevlar linings? Yes and no. Properly installed and used, they will give decades of trouble-free service. Poorly installed or wrongly used, they can do serious and expensive damage to your transmission. When two surfaces rub together (drum and band lining) there is friction, and friction makes heat. Too much heat will crack a cast iron transmission drum and eventually break it.     
What does "poorly installed" mean? Out-of-round. Bands must be perfectly round so that they're not contacting (rubbing) the drum when they're not being used. Some say that installing the bands through the inspection door may distort them out-of-round, and it's best to install them with the hogshead removed.

 How about "wrongly used"? The wrong driving style is anything that causes too much friction/heat. Starting from a dead stop, there has to be a brief bit of slipping as the band starts to squeeze the drum. That's not a problem if you keep it brief. Allow enough slippage to get the car moving without stalling the engine, then hold the pedal down hard. That goes for anytime you're driving in low gear — climbing a hill, going slow in a parking lot, etc. — keep a heavy foot on the pedal so the drum isn't allowed to move. As much as possible, plan your stops. Make them gradual. Close the throttle and let the engine slow you down. When you do apply the brake pedal do it in short bursts to keep the drum well oiled. When you are stopped you will need the clutch in neutral so as to not stall the engine. Some drivers hold the low pedal part way down for neutral. But using the hand lever for neutral assures that there is no danger of going past neutral and letting the band lining ride on the drum.

INSTALLING BAND LININGS
Your new linings will be longer than the bands.
The lining should extend a little past the end of the band. About ⅛" is good.
Install the end rivets, then mash the lining down against the band.


The brass split rivets will be installed through the holes with the heads on the outside of the band.


The rivets are driven in with the split parallel to the band.
You can use a small grinder to make a rivet spreader from a piece of half inch square stock. It should be long enough to stand above the band where your hammer can reach it easily.


After the spreader has bent the legs of the rivet you can pound them flat with a ball peen hammer.
Chewed up Kevlar and a broken band tell the story. Most likely the drum had a crack chewing the lining for many miles before it finally broke.
Note how the outer part of the drum is discolored by heat. A band that is out-of-round, even at its loosest adjustment, can be in constant contact with the spinning drum, building more and more heat. A drive of sixty miles finally broke this drum, but it was cracked and chewing the lining before that.
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