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 outer sprag races ,an oversize 36 element sprag assembly,and a custom sprag retaining plate and spiral lock ring.Modified inner race distributes lube oil to the sprag assembly more efficiently. This drum has been tested behind engines producing over 2000 horsepower/ foot pounds of torque. This assembly includes a custom 4 clutch intermediate clutch pack,heavy duty snap ring and snap ring support.

  
"BRACKET RACER" BILLET INPUT SHAFT/DRUM ASSEMBLY #4CC/BIA        $229.00
An economical upgrade for the street/bracket racer that demands durability.Recommended for most applications producing up to 1200 horsepower/1000 foot pounds torque.This billet input shaft and forward drum assembly stops shaft failures  at the oil holes and turbine spline.The redesigned shaft is CNC machined from aircraft quality E4340 steel billet blanks and then heat treated and precision ground for maximum strength.
 
"PRO MOD" BILLET INPUT SHAFT / DRUM ASSEMBLY #4CC/BIB                  $299.00
Recommended for  applications producing up to 1400 horsepower/1200 foot pounds torque.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 CNC machined from aircraft quality E4340 steel billet blanks and then heat treated and precision ground for maximum strength. The drum  inside diameter is trued,bored out and broached to accept the larger  38 spline outside diameter of the shaft for increased durability.




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. 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/1200 foot pounds of torque. Heavy vehicles, N.O.S, Supercharging and Turbocharging greatly increase failure rates. Reliable up to 2500 HP.
                                                             


HEAVY DUTY 6 CLUTCH DIRECT DRUM WITH 34 ELEMENT SPRAG AND SPIRAL RETAINING RING #4CC/6CDD                                                                      $179.00
This drum does not require the piston with checkball.


HEAVY DUTY DIRECT DRUM WITH 34 ELEMENT SPRAG, SPIRAL RETAINING RING,AND DIRECT DRUM STABLIZER PACKAGE #4CC/DDA                            $249.00
This package is a great addition to builds up to 650 hp/550 ft. lbs. of torque.A custom bronze bushing is fitted to the inside diameter of the drum.The drum end outside diameter of the forward clutch hub is  precision ground to fit the inside diameter of the bushing.Becuase the forward clutch hub is held on center by the mainshaft  the direct drum is forced to run on center,reducing drum wobble,a major problem in the GMTH400 series transmissions.



INTERMEDIATE CLUTCH SNAP RING SUPPORT #400CC/SRS                            $19.99
Easily installs in the intermediate band pin bore in the case and provides support to the snap ring .This stops the case lugs from blowing out,a problem that has plagued the GM TH400.Designed by John Kilgore.

REPLACEMENT HEAVY DUTY 34 ELEMENT SPRAG                                           $69.99


HEAVY DUTY TRANSBRAKE SOLENOID #4CC/TBS                                      $89.00