Motorcycle Repair: 1995 FLSTC, stock air filter, heritage softail

Question
I recently bought a 1995 Heritage Softail Classic with 48,000 miles. The motor has had no upgrades and runs great. The bike was built in April of 1995 so it has the better lifters. The transmission in 3rd and 4rth gear sound like a washing machine. After shifting into 5th it purss right along. Is there anything I can do to help this. Also, how can I tell if I have the stock air filter or if a high flow air filter was ever installed. It has the original air filter cover on.

Answer
You can try some synthetic oil in the trans and see if that doesnt help with the noise. If it continues you will probably have to pull the trans. You could have a bearing going out.
Check the filter and see if it has any company name on it. The other thing you can do is check  the filter. If its paper its stock. If its not its aftermarket.
Good luck and happy riding
Mike