I own a 09 Bullitt. It's been modified and is my daily/occasional track car. Back in February I had a Torsen T2 installed and a new set of 3:73 gears. It has over 100k on the odometer and it was time to give the diff some love. Fast forward a couple months and instead of hooking up well in the corners it started feeling like it was slipping and didn't leave me feeling confident. I had the car into a shop close to me to check on a small coolant leak and to rotate the tires and they noticed that there was too much play in the driveshaft and said something seemed off. I told them about the recent upgrade and they informed me that the lash may be off. I called the other shop and caught a ton of flack for taking it somewhere else which has led me to not go back to the shop that installed it but to have the new shop crack it and take a look. Once they did this was their diagnosis and recommended fix:
""""Notes:
found large amounts of play from pinion movement to when wheels spin. also found rear diff appears to be open. can hold one wheel steady and spin the other freely.
removed cover, noticed gear oil is extreamly dark especially for a fresh rebuilt unit. found 3.73 gears which is the ideal gear for this car. found carrier is an eaton true trac unit which is a worm gear posi, slop is inside carrier and limited slip is not working.
aside from carrier, found preload very loose in total which indicates neither pinion or side bearing proload is within spec, this is likeley why gear oil is very dark. bearings in process of failure. aggressive wear pattern on ring gear teeth, the result of too much backlash. (found .022 backlash, ideally needs to be around .008 - .012)
eaton unit that was installed is known to be problematic, have had or heard of several premature failures. aside from this, ring and pinion was setup poorly.
Rec replace ring and pinion, and carrier. recommending a more conventional opposing plate type posi unit for longevity and performance. (yukon-duragrip posi carrier and yukon gear 3.73 ring + pinion) *?*?*? 31 SPLINE AXLES*?*?*"""
If it was your car what would you do with fixing the issue? Eaton TrueTrac? 31 spline axels? Which manufacturers? Thanks TMO community for your input and feedback in advanced!!
""""Notes:
found large amounts of play from pinion movement to when wheels spin. also found rear diff appears to be open. can hold one wheel steady and spin the other freely.
removed cover, noticed gear oil is extreamly dark especially for a fresh rebuilt unit. found 3.73 gears which is the ideal gear for this car. found carrier is an eaton true trac unit which is a worm gear posi, slop is inside carrier and limited slip is not working.
aside from carrier, found preload very loose in total which indicates neither pinion or side bearing proload is within spec, this is likeley why gear oil is very dark. bearings in process of failure. aggressive wear pattern on ring gear teeth, the result of too much backlash. (found .022 backlash, ideally needs to be around .008 - .012)
eaton unit that was installed is known to be problematic, have had or heard of several premature failures. aside from this, ring and pinion was setup poorly.
Rec replace ring and pinion, and carrier. recommending a more conventional opposing plate type posi unit for longevity and performance. (yukon-duragrip posi carrier and yukon gear 3.73 ring + pinion) *?*?*? 31 SPLINE AXLES*?*?*"""
If it was your car what would you do with fixing the issue? Eaton TrueTrac? 31 spline axels? Which manufacturers? Thanks TMO community for your input and feedback in advanced!!