I've read they ran out of hydraulic lifts towards the end of the production run and fitted some with manual. From what I've heard, the dealer was supposed to upgrade to the hydraulic lift once they were back in stock. Of course that would require you to take your tractor back in for service, so I'm sure many tractors were never upgraded.
edit: This may have been with 169s the more I think about it....
edit:edit: Roland beat me to it.
__________________
-Jason
Cub Cadets: 1200 | 149 | 1650 | 122 | Z-Force S 54
Implements: QA42A | Push Blades | #2 Tiller | Rear Blade | 223A Utility Trailer | And a few mower decks
Gravelys 5260 | CI Walk-behind (Project)
And a couple of Subarus 
|