Re: 3225 Transaxle Seal Replacement
I'm done and I wanted to document this for others. This post is really long. I hope it will be helpful to others.
Odd tools Needed:
Big wrench for wheel hub nuts - 1 5/16"?
2 jaw puller to remove wheel hub
electric heater to help cure RTV in Winter
A helpful friend who doesn’t mind a little oil/grease
5 quarts of fluid
RTV (the service guy recommended the black High Temp stuff)
Engine degreaser and brake cleaner.
(Sorry about the lack of pictures, but my photographer had to visit her parents, so all you get is narrative!)
Start by eating your Wheaties!
The first step should be to remove the HUGE nuts that hold the wheels in place. This is really hard to do and if you can do this, you can do all the rest. If you can't do this, you won't be able to do the rest as I'm describing it. (Note: If you can't remove these nuts, you may be able to disassemble the differential with all the planetary gears, etc., but I'm not going there in this discussion. You can consider that path, or consider taking your tractor to the dealer.)
Place a jack under the axle and remove the wheel and get a wrench onto the center nut. It seems to be 1 5/16" or so. I didn't have the right tools and was able to use a pipe wrench to hold the hub, a big crescent on the center hub and whack the crescent with a 2x4. I confirmed with the shop that it is put on to 250 ft-lbs. Do one side and then the other. You may need to put the wheel back on and put the weight back on that wheel to get the other side done. This is the most physically demanding part of the job.
Once you’ve got both your nuts off, jack up the tractor, place it safely on jack stands or blocks and start stripping. You're going to remove everything from the steering console back except the transmission, transaxle and control valves. Even if you've never done this before, it's pretty straightforward. The tricks include removing the electric plug from the switch from the bottom of the seat before you rip it out and bend the contacts, loosening the hydraulic lift control levers from underneath the left wheel area and removing the light bulbs from the rear lights BEFORE you try to lift the fender over the gas tank. (If the bulbs fall out and end up in the taillights, you'll be able to fish them out when you get the whole fender/running board assembly off!)
When you get to the back plate with the draw bar, you'll need to slip a 14mm wrench up the inside of the frame from the sides above the axle to reach the top nuts at the inside top the housing. You can guide the wrench with your fingers from the top to get it on the nut and then use a socket from the outside to get it all free. If you have a three point hitch, be aware that it's really quite heavy once it's loose! Again, if you have the three point hitch there is an extra cross-member for mounting the hydraulic cylinder and you'll have to remove that too!
When you remove the gas tank, plug the hose with a bolt or pencil so that you don't end up with a fire. Set the gas tank someplace safe.
Since you are here, take the time to adjust your brakes (see the owners manual.) and then remove the brake pad assemblies - rods and all. You will need to partially remove the brake pedal lever to get the right side brake rod out because the tip of the rod won't clear in the space available. The left side is easier.
Use a two jaw hub puller to remove the hub assembly (containing the brake disk) from each side. I used the lug nuts threaded on backwards to create a grip point. It is tightly splined in place, so it has to come straight off. Smacking it to "wobble" it off isn't a good idea. Remove the brake mounting brackets that are 1/2" bolted (and locktited!) to the end of the axle ends.
Trace from the differential lock-out pedal on the left running board to the level on the "front" of the transaxle, remove the 7/16" bolt holding the differential lock actuator lever in place. The bolt is held in place with blue locktite. The order is: bolt, a thin washer, the lever and three washers. You don't need to remove the lever from the cable - just let it dangle. When you remove the drive shaft, the actuator shaft will slide out from the inside.
Now drop the giant U-bolts that hold the transaxle to the frame. (Note: My U-bolts were longer in the back than in the front! Look for differences so that you can rebuilt it "right".) With the U-bolts disconnected, the transaxle will hang there without any issue.
Drain the fluid (5 quarts or less) and remove the filter. If you have clean filter, put it on - or cover that area with aluminum foil. At this point you may want to consider that the floor is going to be covered in oil. I placed several handfuls of sawdust under the unit to soak up the many drips.
Now remove the 3/8" bolts on the center cover. The long screws go on the immediate sides of the differential and go through the metal bars. These bars hold the bearing blocks in place! The medium length ones go in the top and bottom. Remove the gasket and then remove the bolts on the axle cover. The short bolts go along the sides out toward the wheels.
When you get the first cover and gasket off. Take a look at what's in front of you. The horizontal shaft on the top is the output shaft and it has a bevel gear on the right. You'll eventually just pull that straight out, but not right now. The lower shaft is the driveshaft. The big cluster in the middle is "the differential". Find the differential lockout actuator shaft (that you removed the locktited bolt from and note that it is all the way to the far left. The actuator will come out in a couple minutes when you remove the lower shaft unit - and then it probably fall on the floor!
Now go ahead and remove the cover for the axle shafts and look around some more. You'll probably see oil below the axle shafts - outside the differential hub area. This is your leak. You may get away with changing only the inner bearing block assembly on that side, but give some thought to the time you have invested. My dealer suggested not only changing the inner blocks on both sides, but also both inner and both outer bearing blocks and I'm glad he did. One of my outers had a torn seal.
Prepare an area to put the shaft assemblies. I used newspaper and then put aluminum foil on it.
After removing the last gasket, carefully take out the upper shaft - aka, the output shaft, holding your hands over the ends to keep the blocks in place and place on the foil surface. You're not going to do anything with/to this.
The big assembly with the bad bearings now comes straight out and then down to clear the frame. The differential lock-out actuator will come straight out at the same time and probably fall on the floor unless you have a friend to catch it! If the actuator sticks, wiggle it to get it to slide out. Place the actuator and big shaft on the foil.
Clean the old RTV and dirty oily crap out of the housing. You'll probably find some fine metal dust in the bottom of the transaxle. Don't panic as it's normal, but this is why you should change your fluid when it's all stirred up and hot and why you should change your filter and fluid regularly, too. Just wipe it all out and clean it all up with something like brake cleaner so that there is no residue.
The bearings will be replaced from the ends of the axles. I used 000 steel wool to clean up the little surface rust on the axles outboard of the bearings, but inboard of the hubs. Try to smooth it out as much as possible because you'll be slipping the new bearings over this spot and you don't want to harm the seals.
Directions on the RTV used to seal the new bearing blocks in place suggests that the metal should be held at a minimum of 70F for about a day to completely cure. The advice from the shop is that you can fill after the RTV sets for 15 minutes - maybe 30 to 40 in the cold. I did this in the winter and chose to let the RTV cure for about 16 hours using an electric heater to warm the transaxle. If you are doing this in the winter, put away the degreaser and brake cleaner and then set up your heater to warm the area. Degreaser and brake cleaner may be flammable, so don't have or use them near the heater!
Now we remove the bearing blocks from the shaft. The inside ones have a rubber seal that goes toward the center line. The outside ones go either way. Look for differences and do one side at a time. Remove the outer and then the inner bearing block on one side. Note that there is a washer that may be stuck (just by oil) to the inner face of each inner seal. Make sure it stays on the shaft.
Now take your new bearing blocks and prepare to put them on the shaft. Lube up any rough spots on the axle and minimize stress on the seals when you put them over the end of the shaft so that you don't destroy them. Repeat for the other side.
See the next post for the continued instructions...
Near Rochester, NY
Current: Yanmar 424 w/ turf tires, front end loader and 60" mower, Cub Cadet 42" hydraulic rototiller, Spyker 179 spreader, Turfvent 48" plug aerator, CountyLine 25 gal Deluxe Trailer Sprayer, Agrifab dethatcher
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