WM up/down function problem

[Bodger]

I have been fighting a battle with the up/down function on my 95 WMHD40.  Runs fine first thing in the morning but quickly starts slowing down when raising the head.   

• the motor gets fairly hot when running
• 14v out of the up/down control in box
• 14v on red wire when unhooked from motor
• 10v on red wire when hooked up to motor

The motor looks OK - over half life left on brushes
Ran jumper wire from battery to motor and no change
Replaced motor anyway and it still ran a little slower (not as bad but still slower)
Replaced bearings in gear box about 8 months ago
Mast lubed well with ATF and can't feel any binding rolling up by hand

The part that haunts me is the voltage drop when the motor is hooked up.  I've spent quite a bit of time with WM electric tech support (great service) but still cannot find the bug.  If I could get this fixed I would not have a care in the world.  Thanks for any help in advance.

[pineywoods]

Bodger, check the lube level in the up-down gear box. Needs to be full, wm says use atf, I use 90 wt gear oil. I just spent an entire day chasing the same problem. I found the voltage drops to be all over the place. No big drop at any one spot. Worm gears with no lube and a heavy load will develop a LOT of friction.

[terrifictimbersllc]

My 2001 LT40 paperwork specified a synthetic gear oil, Mobil SHC 634, for the up/down gear box lubricant.  WM sold it in 8 oz bottles quite expensive.  I found it available for $15 a quart if my memory is correct, at my local Grainger outlet.  Also the level was to be about half full, so it is just up to a hole having an allen head plug at this position.

[Bodger]

I read a post the other day about having a problem because of a leak in the gear box...I drained and checked the level.  I will drain and replace the ATF with some 90w...It's hot enough now that it should be pretty fluid, eh?  Thanks

[Chuck White]

Hello Bodger
My mill is a 1995 WM LT40HDG24.
Last year, I had the same problem.  After running the mill for a while it would get slow.
I removed the up/down motor and took both brushes out of it and used a blower nozzle on my air compressor to blow the dust out of it.
Just put the nozzle in one of the brush holes and the cloud of dust will exit from the other.
Reverse and blow it out in the opposite direction.

What happened was as the motor moved and heated up, the dust would settle and bind as the motor turned.
When I put it back on the mill, speed seemed to increase by about 1/3.