Pow R Kraft 4 Ton Elect Spliter doesn't fully retract

My electric log splitter has been used for about 4 or 5 cords of splitting and now I see the moving push plate doesn't fully retract. I estimate it is about 4 inches short of full retraction. It isn't stuck, I can push it back all the way by hand, but the hydraulic pressure release or spring (don't recall seeing one) doesn't accomplish full retraction.

I will check the hydraulic fluid again, but doubt that could be the cause.. or a dirty hydraulic vent hold, maybe?

Thanks, I did another physical inspection and noted one of the rods that pull the ram head had a loose nut (not me). I tightened it and eyeballed it and it looks square enough. The other side of the rod is in the "Handle" and has locking nut, so I doubt it changed position (length) I then cleaned the I-beam travel surface, it was dirty and all I did was spray some silicone spray and wipe. The return worked better, but that didn't last more than two or three more splits. The power seems about the same, but boy do I wish I had purchased the 7 ton unit. This 4 ton unit is just short of enough power on a lot of rounds. I have a manual splitter that claims to be capable of developing 10 tons, and I haven't run into anything I can't split with it - but I have to work hard for some to develop enough pressure, assumed to be about the advertised maximum of 10 tons. The little light duty electric is still a help, and I'll try ot keep it running. I getting to be too old to buy anything new, I can't last more that a couple more years doing this type of work.