1997 Ford Mustang Clutch slipping and hesitation on accelor

I have a 97 mustang gt, and I love my car. However, over the last 2 years I have soaked more money into my car than it is worth. I am now noticing that my clutch is slipping. I found the average cost and don't mind replacing that. But I have also noticed that my car hesitates or jerks on acceloration. I replaced the engine last year and no that my pinion seal needs to be replaced. But I don't know that my problems not in the transmision. After driving it accross town I notice a burning smell that I am assuming is gear oil. I've never smelt anything like it. Now I am getting a new smell everyday, but it comes and goes.
If you know what would be causing the hesitation and wether it's related to the smell I'm getting I would love to hear your opinion. I just don't want to drop another $4000 dollars into my car for it to act up again next year.