Poor take off on Craftsman lawn tractor YS4500 (917.27660)
I have a craftsman YS4500 (917.27660) tractor and have been having some drive problems recently.
Last year the main drive belt started slipping so I replaced it with a new one. It fixed the problem for a while but then I noticed the tractor laboring up hills with (what I think is) the transmission making a kind of whirring churning sound - whir whir whir up hills. I have also noticed that I have to kind of stamp on the brake pedal to release it and engage the belt. Also, the brakes to stop the tractor seem to be failing.
I've had the tractor 7 years, I don't think I've beaten on it particularly. I've changed the engine oil and filter every 50 hours, air filter and plugs but have never touched anything else...including transmission fluid...
Anyway, I did some digging around and was able to find a YouTube video for changing transmission oil, at least on a mower that had a drain screw. My transmission has no drain screw so I drained it from the fill hole and refilled it with 2 quarts of 20W50 as advised in another thread which covered my transmission. (351-0510)
Two quarts of grey oil came out of it as well.
However, my problem persists.
I have also noticed that if I am having problems setting off and I pull my toe up the back of the brake pedal I set off at full speed. I had a look underneath and the brake return spring is rusty but other than that it seems ok.
When I release the brake normally the pedal goes about 2/3 of the way back to the top (unless I use my toe). The push rod that runs to the brake system is also not all the way back but when I push it all the way back the spring in the brake system is slack, almost like it's the wrong one (to long) or hooked in the wrong place, maybe because the metal plate is resting against the bolt head that is visible in the center of the picture. I bought the tractor with 8 hours on it so I'm pretty much the only owner and it's never been shop serviced while I've owned it. I've attached a picture of the brake area in the rear showing the spring that looks like it's wrong.
With the pedal not returning all the way I'm guessing that the pulley isn't exerting full tension on the drive belt....should I just buy a new brake return spring (the one for the pulley that is under the tractor and connects the pulley bellcrank to the chassis ?) As I said before, it's rusty but looks ok.
What is the loud whirring sound I hear ? (pulleys or tranny?)
Thanks for any suggestions anyone can give.