[Gary]

I found this site after searching for what the problem may be with an older JD stx38 mower my grandfather gave me. There sure looks to be a wealth of information to be had here.

So, my mower is lugging in gear. It lunges repetitively like the trans is out or maybe something wrong with the rear axle...it makes me feel like I'm in a rocking chair...lol!!!

Any ideas??? Thanks a lot!!!!

Gary

 

[Mark / Ohio]

Welcome Gary!

If the engine is running smooth, first place I would look is to see if the belt might be slipping.

 

[Gary]

Welcome Gary!

If the engine is running smooth, first place I would look is to see if the belt might be slipping.

I wasn't aware the mower was belt driven other than the blades. It is a 5-speed with clutch...Granted I'm sure the belt has not been replaced in many years but it appears to be pretty good with minimal dry rot, etc.

It not only lugs when I mow with it but when the blades are not engaged as well...it feels as though something is slipping and then lunges forward until it propels forward for maybe another 10 feet or so then slips again. It also feels like the rear axle may have lost a couple splines causing it to disengagement with a gear/s...does this make sense??? lol

Gary

 

[Mark / Ohio]

If your missing teeth on gears I would think it would be making a nasty grinding and clunking sound too. Another thought might be a key has sheared on one of the rear tires or the pulley on the transaxle. If so, rust would be the only thing keeping it from slipping on the shaft. You can go to John Deere parts, enter your model and serial number and bring up exploded views to look at.

John Deere - Parts Catalog

Here's a random photo I pulled up which probably is like your setup: