Gravely PTO not working

[Tireguy]

I own a Gravely tractor model 8127. I bought it last summer and it mowed fine. Hooked up the monster snow thrower this past winter and it was awesome. I put the mowing deck back on today and the PTO won't drive the mower blades.

When I engage the PTO the drive shaft & blades turn very slowly (1 rpm), but with no torque (I easily stopped the blades with a stick)

The PTO lever moves OK, but it has always been hard to disengage (like it has to go over-center or something). The transmission PTO lever will hardly rotate/pivot with or without the linkage attached.

Any suggestions? PTO cone clutch ***'y?

Now for the mea culpa: the transmission oil was very low (never checked it last year - just got the manuals over winter). It was down 1-1/2 qt. Could that have seized the PTO clutch shaft or worse?

Finally, can anyone recommend a good source for parts?

I Appreciate the help

 

[2manyrocks]

The first thing to do is to unbolt the mower PTO and make sure you lined up all the parts correctly. If you get the clutch/drive mismatched when you hook them up, the PTO won't work and the linkage will be bound up.

 

[RichardTX]

Richard's is good.

Welcome to Richard's Lawn & Garden

 

[Tireguy]

I bought some more oil and filled to top of the little pipe at top of transmission. It took 8+ qts total (capacity is 6 qt, so it must have been bone dry). I will let sit for a while and see if PTO frees up. The manual says to fill completely to top, but when I started the engine the oil started spraying out of the vent hole in cap. It shouldn't be under any pressure, should it?

I don't understand the instructions in the manual for adjusting the linkage. If I tighten linkage (make it longer), the spacing in front of the PTO lever is ~1/2" max, regardless of how "tight" I make it. It is very hard to engage/disengage. If I loosen/shorten the linkage the lever flops around front-to-back. How much rotation of the PTO lever (part attached to shaft going into transmission) is normal (in degrees)? Mine moves <3 deg.

Thanks for the tip on Richard's. I'll try them.

Finally, does anyone know the red paint color code or source for spray paint for my 1979 model 8127?

I do appreciate the help. So far I really like this tractor and everything I read about Gravely's

 

[hawkeye08]

you only fill it until it comes out the pipe on the side. the one on top is the fill, the one on the side is the level.

adjust your pto clutch and it will probably be fine.

 

[Tireguy]

I re-read the instructions several times to find the transmission fluid "check plug". I will drain the excess oil. It seems too low in the transmission side to have 6 quart capacity at that height, though. Am I still missing something?

Thanks for the tip, Hawkeye08!

 

[RichardTX]

While it seems that the elbow is low, it does indeed take 6 quarts of oil to refill a transmission.

 

[Tireguy]

OK, I drained the oil out until it was level with the oil level plug, then added an extra quart back in. I re-adjusted the PTO linkage, drove it around but no change to the PTO output. When engaged, it still turns very slowly (~1-5 rpm) but has no torque (I can grab it and easily stop it). When disengauged it stops rotating as it should.

Any other suggestions? Or is it time to tear into the transmission and have the clutch replaced?

 

[hawkeye08]

The PTO clutch is dangerous. Please be very careful when working on it. I also caution against buying an ebay unit (hard to tell if they are in good shape).

It might just be stuck but I think it still requires splitting the transmission. Very easy to get things in wrong.

I can't think of any other tricks to get it to engage..

 

[Tireguy]

I got the motor off, looked inside and my PTO has no gap. I got the tansmission off, and have most everything removed and ready to split the transmission case. I encountered three remaining issues:

1) I can't get the wheel hub off the shaft. I am going to rent a pully puller, unless someone else has a better suggestion. (I removed the e-ring and setscrew; I don't have a torch available)
2) I can't get the hex nut off of the brake drum shaft. It's too tight to loosen, and the brake drum spins when I try. I can't hold the tranny, both wheels, and turn the wrench at the same time to loosen the nut.
3) I can't get the fwd clutch hub off the #1 shaft. I removed the retaining ring on the splined shaft, but the hub won't slide off. Will pulley puller work here too? Or does it even need to come off before opening the case? The manual doesn't mention it further once the retaining ring is removed.

I sprayed with WD-40 and will let is sit overnight while I come up with solutions and await any suggestions.

Lastly, I noticed some play in the transmission shafts for the hi/low and 1/2/3/4 speed linkages. Schematic shows two bushings, part 17943 (.756 x 1.125 x .5) and part 17925. Does anyone know the material for both (steel, oilite, etc?) and the dimensions of the second? Or an industry standard replacement?

Thanks in advance,

 

[RichardTX]

WHeel hubs can be an issue. You will likely need a puller and maybe some heat.

Getting the nut off the brake drum usually requires an impact wrench. If it is really stuck, some heat nay be needed. The drum may require a puller.

The clutch consists of two parts. A movable hub with fraction material and a non movable drive plate. The drive plate stays on the transmission. The hub with the friction material should just slide off.

WHen it comes to parts I use Richards. Welcome to Richard's Lawn & Garden

 

[Tireguy]

I got everything apart thanks to your suggestion of the impact wrench, Richard TX. I'll be sending the whole PTO assembly to Richard's, along with a short shopping list of parts and some $$.

Thanks again for the help. It would have taken longer, and I probably would have broken something without the great advice from this site.

 

[Tireguy]

The Gravely beast is back in working order!

It took me about 10 hours to disassemble and 10 hours to re-assemble, plus $600+ in parts, but everything is back in place, cleaned up, and running like a champ.

When I took the transmission apart, the gears looked just like they came out of the factory. I sent the PTO clutch assembly to Richards for rebuilding, ordered a couple of replacement bearings, gaskets, and oil seals, and got everything back together this weekend.

I appreciate the advice and information from the members of this forum who helped along the way.

See pictures in photo gallery: http://www.tractorbynet.com/photos/showphoto.php/photo/9211

 

[Leifman]

Greetings folks,
Is anyone familiar with trouble shooting the walk behind PTO slip clutch. I have a 13Hp 5645 with the brush cutter attachment. The blade started going stationary when it came upon thick grass so I assumed it was the clutch, I changed the friction discs, torqued the bolts down according to spec Slip Clutch Adjustment - Gravely 985103 Service Manual [Page 14] and there was little improvement. I then gave each bolt 1/2 turn more and that did the job for about 5 hrs or so then same prohlem. I did the same again i.e tightened another 1/2 turn and it worked for another 2-3 hrs again and now the springs are almost totally compressed and no PTO drive power. Trani oil is clean 20w50 as our ambient temperature is about 30deg C year round and clutch engages and disengages quite smoothly. Any ideas what I'm doing wrong or missing?

 

[RichardTX]

What likely hasw happened is that the slip clutch is worn out. New ones are available from Richard's L&G (gravelyparts.com)