Never can have too much grease in the mast channels. Go grab about 3 cans of inner slide lube and a can of chain lube and go to town. If it’s gummed up, pressure wash the mast channels and chains and start fresh.
Also make sure you grease the mast j hooks, tilt forward all the way and you should see them where the mast is hung on the drive axle. Grease everything, if they won’t take grease, remove zerk and hit it with the portapower, or zerk cleaner tool. They will gum up and not take grease. When those get worn, it’s not a cheap fix. Grease tilt pins and steer axle, might need to pull floor pan to acces the rearward tilt pin zerk, might have an access hole on the side on some. Side shift should also have zerks on the top and the bottom.
If its jerking or sticking it may need to be shimmed. Run it to the top at full speed, and watch when it slams to the limit. If one side Racks up a bit harder on one side, you need to check shims and chain adjustment.
Chain adjustment should be checked routinely, with every oils service.
Set forks dead dead level and adjust the secondary chains until all mast channels are even on the bottom, adjust freelift chains until the forks are about 1/4 to 1/2 inch off the ground at the heel. There’s a special socket that makes it really easy, or you can wrench it. Chain bolts may need to be chased with a 15/16 fine thread (iirc) chaser (should be that size, may be bigger on the 8k lift). They get gummy and nicked up and cleaning the threads really helps with adjustment.
Set forks about 6” off the ground and forks wide enough apart, stand on forks and transfer weight side to side to check the twist on the carriage. If it’s really loose, might be time for shims or rollers.
shim adjustment is bit more work, gotta disconnect sideshift hoses and chain anchors, lift up. Carriage will sit on floor, back the lift up. You can pull the snap rings off and change shims under rollers, bearings need to be free, and rollers should be replaced if worn. Drive lift to line up the mast with rollers, drop back down and reconnect everything.