312-8 trans not engaging

[Wilsonrl48747 0]

My son's 312-8 trans seems to not engage. I haven't made the trip over to his house to troubleshoot yet, but he said while he was mowing, it felt like it was dragging and then it just quit moving. He tried shifting into low and hi and can't get it to engage. Also, when he towed it back to the shed, he said he left it in gear and it rolled freely. Fluid level shows full.

Any hints on how to troubleshoot to see if maybe this is something simple or if I need to do a rebuild?

Also, does anyone have a manual for the 312-8 itself or the transmission?

ANY help is appreciated.

[Rod(NASNUT) 1]

Check the keyways in the hub that has happend to me a time or 2 :thumbs2:

[Wilsonrl48747 0]

OK, I am hoping its something simple like that. Can you point me where to start? Is this something I need to dig in deep to do? Any diagrams available someplace? My experience is pretty limited once we dig into gears etc.

[Buzz 502]

You can donload a manual for a 312-8 (not sure if it's your model number but should be similar) as well as a transmission manual from Toro. Go to:

https://lookup3.toro.com/request/request.cfm

Put 31-12K804 for model number and 2000001 for serial number.

[Wilsonrl48747 0]

OK, I went and looked at the tractor and found that the rear right wheel hub assembly was flush with the drive unit and the shaft was sticking out about an inch from the center of the hub. The shaft was turning when I would put it in gear. I also noticed the wheel that the brake band grabs was turning when I put it into gear, so I figure that the internal gears are grabbing and turning. I am assuming that all I need to do is loosen the two adjusting bolts on the hub assembly, pull it forward and make sure the key is in the slot and tighten down again. Is there a spacer of some kind that goes between the hub and the body of the differential? I didn't see anything like that on the other side, and I can't see anything on the parts diagram.

Also, are these drives like a limited slip? If one wheel is not getting traction does the other one kick in?

Anything I need to know about fixing this problem that isn't obvious?

Thanks again, you guys are the best

[nylyon-(Admin) 7,432]

Jack it up, take off the wheel then loosen the 2 screws on the hub. Remove the hub and what's left of the sheared off key. Go get a new key from the hardware store, usually under a buck, and put it all back together. Nothing tricky with this fix. There aren't any spacers. I tighten the hub when the hub and axle are flush.

[Duff 206]

Rob, Coach is right on the money. A hint, though - if the hub doesn't want to slide off the axle, do NOT beat on it with a hammer! The axle is only held inside the transmission by a spring clip - a rugged spring clip, but one that can be snapped if you put enough force on it. It would be money well spent to run down to your local auto parts store and buy or rent a hub puller.

Once the hub is off, take a small file and smooth out any burrs left by the screws that lock the hub on the axle. Maybe touch the axle with a little emory cloth. Put some grease on the axle before reinstalling the hub - if you ever have to take it off again, it make the process so much easier.

As you slide the hub back on the axle, keep an eye on the key - it will probably try to slide up and out toward the tranny as the hub slides on. Just tap it softly to "square" it in the keyway as you slide the hub on and all should be well.

The differentials on the 312-8's are not limited slip, BTW.

Good luck!

Duff :thumbs2:

[Wilsonrl48747 0]

Mission accomplished. I didn't even have to buy a new key. The key was still in the slot, held in by some old grease. I did have to go get a hub puller as it just didn't want to come off, but I have been meaning to buy one for a while anyway. I got the hub back on and tightened the set screws and took it for a spin. No problems now.

Thanks for all the good advice guys.

:thumbs2:

[Wilsonrl48747 0]

My problem is back! The hub slipped past the key again after I fixed it a couple of weeks ago. I tightened down the set bolts on the hub and then used the nuts to lock them down further, but my son said that it slipped down the shaft again. Is there something I am missing when I set those bolts to hold it to the shaft?

Should I be using thread lock in those holes to hold it in, or perhaps should I be replacing the bolts? When I took the hub off, there were no marks on the shaft that looked like the bolts had dug into it, but I thought that was a good thing. I did grease the shaft when I put the hub back on, and it was VERY tight, I had to tap it pretty good to get it back flush with the end of the shaft. I am confused for sure. Any help is appreciated.

Rob

[Jim_M 179]

I would replace the bolts. I use cup point set screws long enough to stick out of the hub and use lock nuts on them. You could also dimple the axle with a drill so the bolts lock into the axle, but I never like drilling an axle if I don't have to.

[WHC-125 4]

I would replace the bolts. I use cup point set screws long enough to stick out of the hub and use lock nuts on them. You could also dimple the axle with a drill so the bolts lock into the axle, but I never like drilling an axle if I don't have to.

If you were to drill anywhere I would drill just a slight bit on the keyway set screw spot not on the axle.