312-8 Slipping Transmission

[eo1bart 42]

The other day after plowing I was backing up in low gear and I noticed the tractor was surging. Not the engine, what I mean is when looking down at the rear  wheel the tractor would pause and go every few seconds.

What would cause this? The gearbox was completely rebuilt last summer, also I installed a new drive belt and clutch spring. I've already inspected these and the hubs and everything looks good.

The machine has been working great since all the work was done. Admittedly in the past month I have been working it hard plowing/snowplowing, most of which is on an incline and even though I have wheels weights, filled tires and chains

I have been spinning the wheels a lot especially in reverse. Looking for some ideas before tear-down and differential inspection.

 

[WHX?? 54,245]

Double check the hubs/input pulley first. Put witness marks on them & see if you have sheared a key. 

Any strange noises indicating you may have stripped a gear? Drain the oil and look for bits of silver and metal flakes. 

[peter lena 9,677]

@ e01bart ,  related pulley issues ?  get a helper   so you can see possible  reason / cause ,  your  rotation  relation is  showing you the way  , maybe a low range  look  so you can  ,carefully see what's going on , your recent  hard  driveline  stress , probably woke up a  solid rust related , issue , hub , key way  blow out  , pete

[gwest_ca-(File Mod) 11,962]

You may have backed into some snow and it has got on the transmission pulley/belt causing it to slip. That does not happen for long and the belt gets it's grip back.

Going forward you have usually removed the snow ahead of the pulley so does not happen then. Been there done that.

[Ed Kennell 44,500]

Like Jim said, mark the tranny input shaft/,pulley and both hub/axles.   Then like Pete said get a helper to watch these three points while you make it slip.