| Triumphs Only, Inc. - Triumph Technical Service Bulletin |
Revised First Gear Ratio- TR-6
August, 1973
A revised first gear ratio was introduced on the TR-6 gearbox, changing the ratio from 3.14:1 to 2.99:1. This ratio change was effected by replacing the 33-toothed first gear on the mainshaft with a 32-toothed gear, and similarly, the 16-toothed first gear on the countershaft with a 17-toothed gear.
The gears concerned are directly interchangeable as matched pairs only. Details of part number changes are as follows:
| Description | Part Number |
| 1st gear on mainshaft--33 teeth
Countershaft gear, 1st & reverse 16 teeth on second gear |
152770)Fitted to gearbox number
128107) CC89816 (3.14:1 ratio) |
| 1st gear on mainshaft--32 teeth
Countershaft gear, 1st &reverse 17 teeth on first gear |
152803) Fitted from gearbox number
UKC 0662) CC89817 (2.99:1 ratio) |
|
|