Upon rebuilding the 4T60 and 4T60-E transmissions the final drive sun gear is often found damaged. The helical gear teeth are often pitted and spalled under normal operation. This damage can be the result of overstressing, poor lubrication, or incorrect hardness depth. If the damaged sun gear is not replaced, the planet gears will also become damaged and the entire planetary assembly will need to be replaced. There are three OE gear ratios: 2.84 (38-teeth), 3.06 (34-teeth), 3.33 (30 teeth). This gear is for the more popular 3.33 (30-teeth) applications only.
The Sonnax replacement final drive gear 75884B-01K is made from ultrahigh strength alloy steel hardened to a depth appropriate to withstand high tooth loads. Teeth are crowned to improve lubrication and longevity. This is truely a better than OE quality gear at an aftermarket price.
Contact a Sonnax Parts Distributor.