http://www.searspartsdirect.com/partsdirect/getSubComp.pd?modelNumber=917273404&productCategoryId=1509200&brandId=0247&brandDescription=CRAFTSMAN&modelName=LAWN-TRACTOR&diagramPageId=00001&componentDescription=PEERLESS%20TRANSAXLE%20-%202000-006A&documentId=P0107012&blt=06 If that picture comes up, you'll see the gears in your transmission. You'll see that some of the gears meet at a 90 degree angle. That's probably where your problem is; they are no longer meeting. You can probably repair these yourself, but it's time consuming.

Everything got reassembled on Friday and HIGH_SPEED again works like the mower was new. If you find you're having trouble with the transmission either making a knocking sound when shifted to HIGH or no movement at all in HIGH, take the motor to transmission drive cover off to expose the transmission. Wash off the transmission or blow it clean with compressed air. Cycle the high/low shift lever on the mower handle to locate the high/low shift lever on the transmission. Look at the opposite end of the shaft from the arm where the shift cable attaches to find the gear shift cam; the cam is about 1" long. Look for a small notch in the side of the cam. Just beyond the notch is the surface that pushes on the end of the shifting shaft. The cam pushes on the end of a 1/2" long shaft, pushing it in to select HIGH and letting it spring out for LOW. Use an inspection mirror to see the point where the cam rides against the end of the shaft. If the end of the cam has a flat spot worn at the point of contact, you have found the problem. Only a small amount of metal need be worn away (1/16" - 1/8") for the transmission HIGH gear not to engage fully. As mentioned in the previous post, the replacement cam is Honda part P/N 22532-VA3-801 and sells for about $13. It's a pity there is no way to post some of the photos I took so readers could see exactly what to look for.

You probably have nothing to lose if you clean it up and open to have a look. Normally Honda doesn't service internal trans parts, but maybe you will luck out.

There are a few possibilities, all having to do with excessive wear or loose fit in the directional control linkage. My first suspect would be the control arm on the transaxle case where the directional control linkage ends at the transaxle. The control arm attaches to the directional control shaft (aka swash plate shaft) with a bolt. The control arm has a square shaped hole and the control shaft has a square shaped profile where the two fit together. It is possible that the bolt holding the control arm to the control shaft has been loose and worn away the profile of the two mating parts to the point that the control arm and the control shaft are no longer locked together, but instead are now able to allow the control arm to move (when you move the directional control lever on fender) without affecting the same movement to the control shaft. This is going to require a close up visual inspection of the control arm where it attaches to the control shaft while some body operates the forward/reverse lever to determine if there is a lot of slop between the two components. Normally, there should be no lost motion between the two parts. You may have to remove the bolt that holds the control arm to the control shaft to see if the square hole and shoulder are no longer "square" because of wear.