I have a 01 t/a 6 speed that is making a thumping sound in the original 10 bolt. I have also noticed that the posi is not really working. If going straight it will burn both tires but have gotten stuck in low traction drive ways and grass and such. no dough-nuts at all. I am planning to replace the whole carrier and gears but not sure what to get. looking at a eaton posi carrier and either 4:10 or 4:56 gears. I want to be able to course road race and still drag race some. I guess I drive the crap out of it since it has less than 15000 miles and rear-end is broke. I have a best time of 13.70 in 1/4. I want low low 12's or high 11's may not get there without quite a few more upgrades --like slicks for 1. I just thought I would throw out the question to see what others have tried or think. I am new here so hopefully this isn't a question that has been answered often.. and is there other gear options beside the two listed???