A/T - 700R4 Updated Forward Roller Clutch

TSB 88-23 (May)

Subject: THM 700-R4

SUBJECT:
CHANGING THM 700-R4 FORWARD ROLLER CLUTCH TO LATEST DESIGN SPRAG ASSEMBLY

Early THM 700-R4's were manufactured using a forward roller clutch. When rebuilding one of these transmissions, it is recommended that you update it to the latest design sprag assembly. This update requires using the complete sprag, race and clutch hub assembly.




When updating from a roller clutch to a sprag, be sure to change the input sun gear. Note the difference, as shown in Figure 1. This will make up for the end play clearance because of the taller outer race and elements.




The sprag type outer race has more lube holes, and a larger inside diameter. (Figure 2)

Two different sprag types have been used. The first design sprag contains 26 elements -- the newer type has 28 elements.

IT IS RECOMMENDED THAT ALL CONVERSIONS BE MADE TO THE 28 SPRAG ASSEMBLY.




When installing the 28 element assembly, do not use the black input carrier thrust washer (Figure 4).




The forward sprag can be assembled backwards. Be sure to check for proper free-wheeling and locking rotation when assembling.

The part number for the latest complete forward sprag assembly is:

PN 8657929