You can definately swap the top and bottom halves or buy a new bottom directly from Super GearBox Direct. The part # is R100-003M-A0427 and the last few I purchsed were $42.50 ea.
https://www.superiorgearboxdirect.c...boxdirect.com/account/access?redirect=/account/docs/view/NSDuBM-wiUi1TkoTCwpOaA
I have found that if the driveshaft splines are worn, or the u joints are worn or the yoke is egg shaped where it fits on to the center box are the causes for sheared bolts. After replacing the bad driveshaft parts, I helicoil the holes in the bottom case and that gets everything back up to snuff.
The other issue that can cause mounting bolts to shear, although not as frequently as driveshaft issues, is a worn bearing on the output shaft of the box.

 

You can definately swap the top and bottom halves or buy a new bottom directly from Super GearBox Direct. The part # is R100-003M-A0427 and the last few I purchsed were $42.50 ea.
https://www.superiorgearboxdirect.com/account/access?redirect=/account/docs/view/NSDuBM-wiUi1TkoTCwpOaA
I have found that if the driveshaft splines are worn, or the u joints are worn or the yoke is egg shaped where it fits on to the center box are the causes for sheared bolts. After replacing the bad driveshaft parts, I helicoil the holes in the bottom case and that gets everything back up to snuff.
The other issue that can cause mounting bolts to shear, although not as frequently as driveshaft issues, is a worn bearing on the output shaft of the box.

Walker56 - you are correct, it does get easier the more you do it! I flipped the halves of the gearbox, got everything back together, and started to diagnose what might be wrong in the driveshaft to cause the bolts to shear. When I engage the blades there is a noticeable vibration, and I'm sure that what is causing the problem. All ujoints seem tight, the output shaft from the gearbox is also tight. The only loose play I can find is in the yolk that attaches to the shaft on the "t" gearbox on the deck. Is it safe to assume it is the yolk and not the shaft on the gearbox that is worn? Can I replace just the yolk at that u-joint or do I need to replace the whole shaft assembly? How do I diagnose the exact problem and proceed from here? Thanks in advance for your expertise and help.

 

Walker56 - thank you for the detailed reply. I guess I need to pull the gearbox, try switching the halves (will I need any new seals or gaskets?), and then do a thorough check of the drivetrain. I may be back in touch with you as I go through that process. Do you have any tips on the quickest/easiest way to get that gearbox out? After the time I spent getting it removed last time I’m almost thinking it would be quicker to pull the motor so the gearbox could be pulled straight back and out. Again, thanks so much for the information... greatly appreciated.

 

There is no paper gasket. I use what the factory suggests, Loctite 598 and I have never had a leak. As for the seals, the only ones you can replace are the output shaft seals. The input shaft seal is part of the input shaft which is not serviceable. If the input shaft is grooved, a new seal will not help.
Here is the service manual for the box
http://www.superiorgearbox.com/bevelgearmanual.pdf
As for removal, pulling the engine is a last resort. This is what we do to remove the box without having to pull the engine. Pull the deck and both driveshafts. Place a jack under the right side and jack it up. Remove the right side tire. Remove the PTO belt and blower belt. Remove the PTO pulley as well as the blower pulley. Remove the band brake. Remove the four retaining bolts for the box. Tilt the rear of the box up toward the center of the machine and pull up and back. The output shaft should just clear the frame member on the right side. Pull the box out from the right side. I know I am making sound easy and I realize it is a pain but it can be done. I think it is one of those things where the more you do it, the easier it will become.

 

Man, what a wealth of knowledge! I'll try this method. It seems the last time I did it I didn't think I could easily get the pulleys off because of the angle and limited space. I actually removed the jack shaft and it's frame. The bottom hex head bolt was a pain... I had to take the metal chute guide off the front of the blower to access the hex bolt. I also had to remove the blade engage safety switch and then the gearbox came out without removing the pulleys. As I said... pita. I probably spent 6 hours taking it out and reassembling. I'll try your directions... thanks!

 

It takes some finagling but the pulleys come off eventually. Once they come off, I put never seize on to facilitate easy removal in the future. The ouput shaft pulley for the blower is the biggest pain. Prior to removing the PTO mounting bolts, I take an eight point socket with a universal on a long extension to get the bolts that hold the pulley to the shaft. Then, using the box as a steady rest, I take a long pry bar and move the pulley off of the shaft. The PTO drive pulley bolts come off easily if you engage the PTO. The belt holds the pulley from slipping. You will figure out your own short cuts as you perform the task in the future.

 

First, i would check the weldment where the box bolts to for cracks. You have to look from the bottom as you engage the pto handle with the machine off. Pay particular attention to the welds where the plate attaches to the frame. The yoke cannot be changed by itself. The input shaft for the center box can wear requiring replacement. Check for looseness between the front half and back half of the driveshaft. The splines should feel solid with no looseness. You really should change them as a unit.

 

Here is a picture of a worn input shaft for the center box. Notice the discoloration from the metal transfer when the driveshaft was spinning on the input shaft after the shear pin broke.

 

No cracks in welds. The only looseness in the driveshaft is where it attaches to the splined shaft that comes out of the center box on the deck (the connection where the shear pin is located). It appears there is a roll pin that holds that yolk onto the shaft. How do I know if the worn part is the female spine on the yolk, or if it is the male spline on the shaft from the center box on the deck. Where is the best place to order replacement parts online?

 

I saw your picture after I posted my reply. I guess the yolk and input shaft are not splined... I thought they were. Can you replace just the input shaft and not the whole center gearbox?

 

Yes you can. If you have the center box with a shear pin, like the picture I posted, order part #776427. It will be cheaper than ordering the part at the dealer (P056). The newer boxes have the shear pin eliminated.

 

These are the splines that I am talking about on the front driveshaft.

I dont know if you can see it, but the driveshaft yoke hole is oblong. Combine this with the worn input shaft of the center box and you got a perfect scenario for vibration.

This is what worn splines on the input shaft of the pto box looks like. These splines wear and then there is a loose fit into the back half of the driveshaft.

 

This is what you need.

 

I can't thank you enough for sharing your knowledge. I know just enough to be dangerous, lol. I simply enjoy working on my own equipment, and hate to pay the high shop charges for something I can do myself. It appears I could order everything including the pto gearbox, driveshafts, and center deck gearbox for around $950. I'm sure that is less than the shop charges would have been just to diagnose and repair my original pto gearbox problem. I think the pto gearbox and output shaft are fine, I just need to determine how many of the other parts I really need. When I engage the blades it appears the looseness, movement, and vibration are at the point of connection between the center deck gearbox and the yolk where the shear pin is. Hopefully when I pull that connection apart I can determine if it is just one side or both. My lawn maintenance business is part time, and at 69 years old all this activity keeps me occupied. I will probably be seeking your help again at some point. Let me know if I'm wearing out my welcome. Thanks again...

 

I would suggest replacing the input shaft for the center box and both the front and rear driveshaft. As long as the weldment is good, and the pto box internals looked good when you opened it up, you will be good to go. Walker went away from the shear pin on the center gearbox a few years ago. They also went from aluminum boxes to cast iron. The center boxes (shear pin/non shear pin)are not interchangeable and require two different front driveshafts, just an fyi.
Here is an illustrated parts list for a 48" deck center box with shear pin So you can see how it goes together
http://www.walker-ag.com/images/Getriebe/7751-16.pdf

 

Just so you are familiar, Walker has made several revisions to driveshaft design and gearbox design over the years. Older driveshafts do mot have splines between fron and rear portions. They use a male square on the front driveshaft and a female broach on the back driveshaft. Older center gearboxes did not have shear pins. They had woodruf keys. Then they went to shear pins. Now they went back to no shear pin and brought back the woodruf key.

 

I disconnected the yolk and center deck box shaft. The shaft is definitely worn and I think I can see some egg shape wear in the yolk. Pictures above.

I plan on replacing the driveshaft and center box shaft on the deck. Do I need to order new seals for the shaft replacement or can the old be used? Any special tools required?

 

Also, my deck boxes are cast iron, not aluminum. Is the shaft part number you quoted the same?

 

You definately need a new seal. The seal part number is Peerless 788099. The input shaft is the same. Walker part number P056, Tecumseh 6509-P1 or Peerless 776427.
You need some basic hand tools, snap ring pliers, etc.
Remove four cover screws, drain box.
Remove the output shaft, output gear and two output bearings. Mark the box or take a picture so you know which side the output gear is on.
Failure to do so, could have the box rotating in tbe wrong direction.
Remove the snap ring from the top of the input shaft and remove the input gear.
Turn the box over and remove the seal protector washer.
Remove the seal
Remove large snap ring holding input shaft lower bearing.
Tap input shaft out of box from the top with a brass punch.
Remove snap ring holding input shaft bearing to input shaft.
Remove bearing.
Reverse procedure to install.
Note: when you go to reinstall the seal, lubricate the shaft where the seal rides with some 90w oil. You have to protect the shaft with some form of a shaft protector or you will risk cutting the new seal as it rides over the new shaft.

 

Researching some parts diagrams, I found that Walker was using Von Rudden (sp.?) hd cast gear boxes for a while. My machine is a 2007. How can I tell if I have the peerless cast box or the Vonrudden? I imagine the shafts are different.

 

The VonRuden box was an assembly that had to be returned to VonRuden to be repaired. There are no repair parts available for it. I will try and get a picture for you. Goigle Walker Mower Cast Iron Gearboxes and see if the images match yours. That VonRuden gearbox set was a 1K option at the time. It did not work out very well. There were a lot of issues.

 

Post a picture of your deck gearbox setup.

 

Here are pictures of the Von Ruden gearbox for a Walker. The VonRuden Boxes have the distinct circle in the top of the box vs the four removeable screws and top cover on the Peerless. Post back what you find.

 

Here is a video about replacing a Walker gearbox. Toward the end of the video he speaks about blade timing. If you dont time your blades after gearbox replacement, there will be a lot of carnage. I wanted to be sure you were aware of blade timing

 

Here are pictures of my gearbox. If I had looked further I would have seen it was a peerless cast iron gearbox by the label. It appears the right gearbox is also leaking. My plan is to replace the seal in the right gearbox, the shaft in the center gearbox, and the driveshaft that connects to the center gearbox. Now I just need to figure out the best place to order parts. Thanks walker66 for your help.

 

Just Google the part numbers I gave you. I have purchased them from
http://www.mowtownusa.com/Peerless-Parts_c_2602-12.html
By the way, the seal for the end box is Peerless 788029
Dont forget to check the play in the splines between the front and rear driveshaft. I would replace both as a set.
There are very few dealers for Walker parts on the net. You will probably have to go to your local dealer for the driveshaft.

 

I would look at the output shaft of the end box before replacing the seal. If the shaft is worn or a bearing is worn, a new seal is fruitless