Leaking from the rear

I went under my car and i noticed that i have oil on the rear of the torque arm. I checked the bolts on the rear end but there is no leaks on it. I had the tranny rebuilt about three months ago. could the leak be coming from the drive shaft. Also could this be the reason why im getting a thump from the rear when i punch it???? I am also thinking of changing the gears. any advice on this will be helpful as well. The biggest mod that i have done is install a shift kit when i got the tranny rebuilt. Any info would be helpful...

so you dont know exactly where the fluid is coming from?

no i dont know where its coming from. i think its from the drive shaft but im not sure

well if it is coming from the front of your differential. then it is your pinion seal. that clunking sound could mean your low on fluid or some od the gears are starting to strip out. is this car your daily driver?

yes this is a daily driver. i checked the oil today and the oil is thin. if i change it will that improve the problem??

yes..it would also help ni case you have any shavings laying around in there...

im thinking of changing the gears in it. i was going to go with slp 3.23 gears. will that give me a good response when i slam on the gas. also do you happen to know a good place to get this as well as some kyb shocks????

on buying parts. Jegs or Summit is your best bet. you can check them out online. on the leak problem. if the fluid is red it is trans fluid. if it is thick and smells terrible it is rearend grease.Once you smelled rearend grease you will remember it forever !!If you can get under your car and follow the fluid from the back of your car to the front that will give you an ideal where it is coming from.Make sure you have someone that knows rearends to put your gears in. There are special tools you need and things that have to be perfect.