Lawn mower deck lifting cylinder

[Onefastgsx]

I have a cylinder on my mower that raises and lowers the deck. When I got the mower out this year it doesnt have the power to lift the deck anymore. It goes in and out just fine without a load, but wont work under pressure.
Replacements are $600 and that's over half of what the mower costs. Where do I start to figure out what's failed? Just take it apart and look for warn parts? I'd much rather replace a part on the one I have instead of forking out $600. I just dont have much experience with cylinders like this

 

[metaleltr]

Search for electric linear actuator. Should be able to find a suitable replacement cheaper. Check northern tool and surplus center.

 

[JRC3]

What is the exact model number of the mower? I know I can find one way cheaper.

 

[Onefastgsx]

What is the exact model number of the mower? I know I can find one way cheaper.

It's a Ferris Criterion 320

 

[tdkkart]

Looks like it could use a healthy dose of maintenance. Disassemble it and lube the moving parts, check the motor brushes, you might be amazed.

 

[The Cobbler]

Looks like it could use a healthy dose of maintenance. Disassemble it and lube the moving parts, check the motor brushes, you might be amazed.

x2 on that

 

[JRC3]

It's a Ferris Criterion 320

That's the model but the exact model number would be more precise. It's typically on a sticker or plate with the serial number.

 

[Onefastgsx]

I took the cap off the gearbox and everything was surprisingly clean and didn't show any signs of wear. There was still plenty of grease coverage on everything.
I pulled the motor case and didn't see any signs of parts that got hot or anything out of the ordinary. The brushes still have tons of life.
I've run it in and out a few times here on the bench and I notice the shaft starts to wobble when it's about 2-3 inches from fully extended. I have to look into more to figure out how it connects so I can pop it off and inspect its internal parts