Tractor Repair: 1973 INTERNATIONAL 574 TRACTOR TORQUE AMPLIFIER, torque amplifier, clutch plates

Question
A friend of mine owns a 1973 I.H. 574 tractor with a T.A. The T.A in this tractor has not been working for sometime now in T.A mode only in direct drive. This past fall, his grandson accidentally shifted it into T.A mode and now the tractor will not move in either direct drive or T.A mode. What could be causing this, and what, if any is a remady? Also, can a person eliminate the torque amplifier all together and install a "dummy" shaft in it's place? Thank-you in advance!!!! Any help in this matter is greatly appreciated!!!

Answer
Hello,

  The TA consists of a hydraulically applied direct drive clutch that drives in high, and a mechanical overrunning one-way sprag clutch similar to a ratchet that drives in low.  It's quite common for the mechanical sprag clutch to wear out and slip, causing it to work in direct drive only.  When it won't work in direct drive, either the hydraulic direct drive clutch plates are worn out, or there is not enough hydraulic pressure to lock up the clutch plates.  If it won't move in direct drive or TA mode, both parts of the TA have failed, the main clutch has failed, or the transmission input shaft is broken.  Lift up the clutch pedal and see how much free travel is available.  You should be able to lift it a few inches higher than it normally sits in the released position.  If it won't lift any higher, either the pedal linkage needs adjusting or the clutch is worn out.  With the engine running, try to shift it into gear without pushing the clutch pedal and see if you can grind gears.  If not, then the transmission shafts are not turning because of a main clutch problem or broken input shaft.  If you can get the gears to grind, then the TA will need to be repaired or there is not enough oil being supplied to the direct drive clutch.  Yes, there is a TA eliminator shaft kit available.