Gearbox and Differential July 7, 2015August 19, 2016 admin Engine With the gearbox now suffering from the typical 4th gear syncro wear issue, it seemed a good opportunity to not only drop a Quaife ATB in there but also have a play with the final drive (FD) and ratios. Replacing the FD with a 4.73 (15/71) from a TL4 021 meant I needed to consider ratios too, as 1st to 3rd on the stock 200’s TL4 031 would become too short with that FD. Therefore I have used a TL4 003 from the early 197 as this box has a longer 1st to 3rd that will stop those early gears from being too short. Also the 003 has the shorter 5th and 6th (which the TL4 024 from later 197’s does not), and when combined with the 4.73 FD will make for a much shorter setup that my stock 031 box 😀 Before (200 TL4 031 with stock 4.3 FD) and after (197 TL4 003 with 4.73 FD) ratios in the following image. New 6th gear will be as my 5th currently is!