Transaxle Question (hard shift/ go into gear)

I have a Murray Select 40" cut (Model 40500x8E)2004 equipped with a Dana (Spicer) 4360-152 5-speed trans axle. Last time I mowed I noticed the transmission was getting hard to go into gear, specifically second gear. From neutral to first is ok, I feel a hard clunk, but going to second I have to sometimes jam it in with the clutch engaged engine running. Engine off yields the same results. The shift-link has an adjustable nut I have tightened it one turn, two turns is too much, the only difference I noticed was shifting felt a little smoother, but still hard to shift. Also going from reverse to neutral is a right, up, and slightly over to the right again, it sometimes gets stuck on the second motion going up after going right. It pulls fine, and I don't hear any excess noise like chattering or whining. The brake and clutch were adjusted at the start of this season in March.



So, my question is can I change the transaxle fluid and remedy this problem, or is it more in depth. I know a little about transaxle but not much.

Not sure if it helps or not but i'm not sure the gear fluid has ever been changed this mower was my brother in laws, and I inherited it last year. He originally purchased the mower in 2004.

On the bight side I have a peerless 6 speed as a backup 206-545C



Thanks in advanced --Richey