So far, The Dog is running AE86 LSD, a W58 gearbox conversion, RX7 front calipers and T3 bits which are all somewhat common in AE86 scene. Yesterday, my Charmant is getting even similar to a four-door Hachiroku with this finally reaching my doorsteps from Japan.
43-teeth ring gear and 10-teeth pinion for a T-series diff, giving me a 4.3 ratio. You know what car these gears come stock in? Exactly: AE86. Ever since i upgraded to a W58, i have wanted a final gear ratio increase to recoup the loss of acceleration from the box's taller ratio compared to T50. While a 4.778 ratio might give me even better acceleration, i don't think it's really necessary for a turbocharged daily driven car, hence a 4.3 was chosen. Besides, it's already quite an increase from the stock 3.909 ratio coming from 43:11 and much cheaper.
Here's the 10 teeth pinion..
and the ring gear..
Although both a 43-teeth 6.7 inch ring gear, the one from the 4.3 ratio has taller dimension compared to the 3.909 which is of course required to reach the smaller pinion gear diameter.
Here's the pinion gears side-by-side (commonly known as "gigi nanas" or "pineapple gear" here for obvious reason). The left one was the old 11 teeth pinion.
I had to replace one of the conical bearings and oil seal. Bearing number was M86610. Some shims with various thickness was needed as well to adjust the bearing's preload.
Last but not least is the backlash adjustment. There are some things better left to be handled by the expert and working on diff pumpkins are one of them. Seriously, i had no idea that gear to gear contact is such a delicate work!
After everything was put back together, a test drive was done and as expected, it accelerates much better and the rear wheels lock easier. Best of all, the whining is now gone. I guess the previous gear ratio was not adjusted properly and caused the whining.