Lotus EA60 transmission (Aisin BG6)
I would re-build the box. All Toyota (Aisin) parts except for 3,4,5,6 gears in Lotus Close ratio (Sport) gearset.
Below for info:
The faulty Lotus installed single CR 4/5 input gear in the Toyota EA60 was fixed in cars from mid 2012. The following may be useful in determining cars that are likely to be affected:
Lotus changed 3,4,5,6 gears for their Close Ratio or Sports box from VIN CHxxx10452 onwards to Lotus part no. B132xxx and in mid 2012 changed the specific 4/5th input gear identified as problematic from part no. B132F0047F to B132F0160F, which is used in current production Evoras and Exige V6's.
Change over to rectified Lotus parts was on mid MY12 cars. Sports Ratio (CR) Gearbox, from VIN CHxxx10452 onwards and Lotus inscribed Gear Box Serial no.GB1564 onwards.
The Lotus Gearbox Serial number (GBxxxx) containing Lotus CR gears is easily identified as is etched by Lotus onto both the transmission casing and the bell housing.
For re-build:
Main parts needed -
4/5 Input gear A132F0160F
4 Output gear B132F0051F
5 Output gear B132F0053F
Optional upgraded parts that were changed later (about 2016) to improve shifting -
Shift fork-No.1 (mod) S/Ratio A132F0349J
Plate-Interlock-modified (SR) A132F0220K
Gate-Gearshift (SR) A132F0206F
Note: CR, SR, S/Ratio, Sport, are Lotus Close Ratio gearset.
Aftermarket improvement for longevity for tracked cars -
Brass slipper pads for selector forks. The above No.1 shift fork is stronger and comes with brass slipper pads.