When researching or shopping around for a GMTH400 transmission or parts you will commonly come  across the description "high performance 34 element sprag and drum assembly".This is a factory part that was  used in the early GMTH400 transmissions as well as the newer GM4L80E transmissions.Although this is much stronger than a stock spring and roller clutch assembly it does have its drawbacks.This industry accepted urgrade gets in trouble at 750 horsepower/750 foot pounds of torque,especially in drag cars with a transbrake or manual valve body that uses a fixed high line pressure.As a matter of fact this is usually the only item that needs to be periodically replaced on most properly race prepped GMTH400 transmissions.When the sprag fails the transmission will no longer have second gear.Are you tired of intermediate sprag failures and the maintenance and down time they cause?  Our in house CNC machined  Super Comp Direct Drum and Oversize Sprag  Assembly is the answer. This custom drum assembly is fitted with  oversize  tool  steel inner and  and outer sprag races ,an oversize 36 element sprag assembly,and a custom sprag retaining plate and spiral lock ring.Special machining of the outer race delivers a constant supply of lube oil to the sprag assembly. All this translates into a drum that can handle up to 2000 horsepower/2000 foot pounds of torque reliably.Due to the larger outer sprag race this assembly comes with custom set of 4 intermediate frictions,4 intermediate steels,a modified pressure plate and a heavy duty snap ring.

  
                                     
E4340 STEEL BILLET INPUT SHAFT / DRUM ASSEMBLY #4CC/BISD      $249.00 The input shaft and drum of the GMTH400 has been known to break in competition applications or vehicles with over 750horsepower/750 foot pounds of torque. Heavy vehicles, N.O.S, Supercharging and Turbocharging greatly increase failure rates. This oversized Billet Input Shaft and Forward Drum Assembly puts an end to shaft breakage and shaft spline stripping at the drum.The redesigned shaft is machined from aircraft quality E4340 steel billet blanks and then heat treated for maximum strength. The drum is resplined to accept the larger outside diameter of the shaft for increased durability. Reliable up to 2000 HP.Machined in house on our CNC maching centers. 

E4340 STEEL BILLET INTERMEDIATE SHAFT #4CC/BIS                              $229.00
The intermediate shaft of the GMTH400 has been known to break in competition applications or vehicles with over 1000 horsepower/1000 foot pounds of torque. Heavy vehicles, N.O.S, Supercharging and Turbocharging greatly increase failure rates.This redesigned shaft is machined from aircraft quality E4340 steel billet blanks and then heat treated for maximum strength. Reliable up to 2000 HP.Machined in house on our CNC maching centers.

E4340 STEEL BILLET ROLLERIZED  CLUTCH HUB  #4CC/CH                      $179.00
The forward clutch hub of the GMTH400 has been known to break in competition applications or vehicles with over 1200 horsepower/1000 foot pounds of torque. Heavy vehicles, N.O.S, Supercharging and Turbocharging greatly increase failure rates. Reliable up to 2000 HP.
                                                             


HEAVY DUTY 6 CLUTCH DIRECT DRUM WITH 34 ELEMENT SPRAG AND SPIRAL RETAINING RING #4CC/6CDD                                                                      $149.00
This drum does not require the piston with checkball.



REPLACEMENT HEAVY DUTY 34 ELEMENT SPRAG                                     $59.99


HEAVY DUTY TRANSBRAKE SOLENOID #4CC/TBS                                      $69.00