Hello everyone.  This is my first time posting on this site (or any site for that matter).  I have a problem with my Toro lawn tractor, and I hope to get some solutions here.  The tractor is a Toro 16-38HXL, built in 2002 and bought new by me in 2002. 
The problem is my inability to adjust the deck slope to be within the range specified in the owner’s manual.  My deck slope was 2.25" lower at the front than at the back, whereas it is supposed to be only 1/8" to 3/8" lower at the front. This extra deck slope causes the mower to cut poorly; the grass is varying heights and I have to go over each area more than once.  The blades are new and sharp.  There are no broken parts and nothing is bent or loose.  I have had this tractor for 18 years, and this only became a problem last year. 
I have run the front adjustment bolts all the way in, which raises the front of the deck.  This helped some; the slope went from 2.25“ lower at the front to 1.25” lower at the front.  But this is still a long way from the small slope called for in my owner’s manual.  Also, I have adjusted the rear hangers every which way, all with no improvement. 
There are two threaded metal rods which also help support the deck.  These rods run from the main tractor frame rearward and connect to the rear of the deck.  My owner’s manual specifies a particular length for these rods, but never says what they are for, or when/why/how to adjust them. 
Can anyone offer advice on how to solve my problem?  Has anyone else run across this problem?  What could have suddenly changed last year after I owned the tractor for 18 years?  Thank you for your help. 

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Scott, 
Thank you for your input.  I had previously adjusted the front two link bars all the way they could go.  That helped some, but not enough. 
 
I decided to mess around with the two longer link rods that run from the main frame to the rear of the deck.  The owner's manual says to set them at a specific length and that's all they tell you.  They never say if or when those two rods would ever need adjusted to anything other than their specified length.  With nothing to lose, I turned the adjusting bolts on those rods, which tried to push the rear of deck rearward.  That provided a similar effect as when the front link bars try to pull the front of the deck forward. 
 
I'm not sure if I am explaining that clearly, but the good news is that it worked!  The deck is now set with the proper, very slight, slope.  The results are clear when I cut the grass.  It looks great and didn't require multiple passes.  
 
I tried to think of reasons that this whole problem could even arise after 16 years when there are no visibly loose or bent parts.  My only theory is that there may be some wear in the bushings where the front axle mounts to the main frame.  See, the front deck hanger links are attached to brackets that mount to the front axle.  If the axle bushings are worn, the axle could tip forward, making the front hanger bolts seem too short.  I did not get way up in there to check that - maybe that's a task autumn.  
 
Thanks again for the help.  I'm calling this problem solved!  

Tom,
I know it has been a few years since your post, hopefully, you will receive this notification.  I am having the same issue.  I did notice that the front axel is loose and will tilt toward the deck.  This causes the front of the deck to drop.  did you find a similar problem with the axel?  I cannot find any suggestions for repair.  Bolts are tight and no bent parts.  The only thing I can think of is the "spacer" is worn or missing.
 
Thanks,
Rich

Might want to pull the loose / "tilted parts" off for inspection of excessive wear.
 
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