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K.B.-826
01-16-2005 15:07:29
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Re: TA Problem? in reply to PAULIH300, 01-16-2005 11:39:56
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Definetly sounds like your ramp and rollers are on the way out. The Mechanical TA used in the smaller IH's is a planetary unit. It is made up of an input shaft, a 7" clutch, a planetary carrier, the planetary unit, the overrunning clutch, known as the ramp and rollers, and the output shaft. Power enters the unit through the input shaft from the engine clutch. When the lever is ahead, (DD), the 7" TA clutch locks the input shaft to the planetary carrier, and the whole assembly rotates as a unit, resulting in no reduction of speed. When the lever is pulled back, the TA clutch disengages, allowing the power from the input shaft to enter the primary sun gear in the center of the planetary unit. The primary sun gear turns the primary planet gears, which are attached to the secondary planet gears, which turn the secondary sun gear, which is splined to the output shaft, resulting in the gear reduction. If the planetary carrier wasn't held still with the lever back, it would just freewheel around the planet gears, and the tractor would not move. This is why the overrunning (one-way) clutch, or ramp and rollers, is used. It is located between the output shaft and the planet carrier, and locks up whenever the planet carrier tries to turn faster than the output shaft. If it goes bad, the planet carrier will just freewheel. One more thing about the ramp and rollers- since it is a one-way clutch, it will lock up whenever the planet carrier tries to turn faster than the output shaft. However, if the output shaft tries to turn faster than the planet carrier (traveling downhill in TA) the ramp and rollers will overrun, causing the tractor to freewheel right down the hill. That is why you never go downhill in TA.
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