C-120 Cracked Transaxle/Gearcase

[RoadScholar 23]

Hello All,

 

I have a 1974 C-120 Model 1-0490, hydro, purchased from the original owner 20 yrs. ago. Multiple attachments including 42" deck, dozer blade, snow blower, and cart.  Well cared for, used for both mowing and snow removal. Original Kohler K301 rebuilt professionally with 72 hours on it.

 

I've been visiting Red Square for years and gleaning all kinds of useful information. However, I've now got a problem that I haven't really found any topics on, and I've signed on to see if anyone can offer any help or advice.

 

While mowing last week, I noticed that the hydro was lagging a bit, and I figured it was probably a bit low on fluid. Pulled it into the garage and immediately noted a thin stream of oil running  out of the gearcase/transaxle.. Closer inspection revealed a crack in the bottom of the gear case on the right-hand side:

 

 

I had no idea how this happened, as the C-120 is gently used. My conclusion was that I must have started the crack this spring when I used a floor jack to raise the rear end to remove the tire chains -- under the gearcase, of course. I've been doing this for years, with no ill effects, but it looked like karma had caught up with me. BTW, I did not notice any unusual sounds on the run-up to this.

 

I briefly thought about getting it brazed, but looking at the gear case disassembly requirements and the parts drawings, I reconsidered. So, I let all the fluid drain out (or so I thought), then used my Dremel tool to scour it clean, as shown in the photo, and cleaned the area with solvent. Next step: JB Weld Original. I figured there is no real pressure on this area, all I needed was something to keep the oil from leaking out.

 

I let the JB Weld set for the recommended 24 hours, changed the oil filter, topped off the gear case with synthetic 10W-30, and off to mow the rest of the lawn. All went well for about 20 minutes, and then I looked down in the grass and saw my JB Weld patch laying amongst the dandelions. It seems some transmission oil continued to leak out after I applied the JB Weld, enough to mess up the adhesion. Bonus: I now have some alien-looking "crop rings" in my lawn where the oil leaked out while mowing.

 

I undid the push valve and managed to push the thing back into the garage. Further investigation revealed even more cracking:

 

 

Note that it appears to have extended into the oil drain plug. I haven't cleaned it up yet for a closer view, but it also looks like a hairline crack may be started in the LH side of the case:

 

 

Overall, a really good way to ruin your day. I can only guess that something has come loose in the gearcase and is getting caught between the gears and the case, although I did not hear any unusual noises.

 

Even if I took it apart, it now looks too far gone for a brazing repair. I don't have a lot of time right now, but I might be able to swing removing the existing transaxle and replacing it with a donor one. But, I've searched the internet for a replacement transaxle/gear case, with no luck. I do have a really good small engine repair shop here to fall back on, but at $65/hr. that will add up fast. Nor have I been able to find much in the way of service instructions for this gearcase -- there seems to be a lot of info on the 8-speed tranny, but not much on the hydro. I did find a CD on Amazon that claims to have service manuals for a wide range of Wheel Horse tractors and parts, but it has no reviews at all.

 

My other choice is to put the tractor and accessories up for sale "as is" and move on with a new or used john Deere or whatever is available -- I wouldn't mind at all seeing it go to a good home (or parted out, for that matter). I've gotten over 20 years of service out of this tractor, with the replacement of a few expected parts (fuel pump, starter motor, tie rods, tires), and of course the cost of the rebuild on the Kohler. But, since I paid $500 for all of it to begin with, I can't really complain.

 

So -- what to do? Any thoughts, comments, suggestions? Words of wisdom? As you might tell, I'm torn about this issue, and  hearing from some fellow Wheel Horse enthusiasts would be most welcome.

 

Thanks!

 

 

[Achto 27,576]

 

Just a suggestion - a 2hr drive to Biglerville PA this Thurs - Sat might score you a set of cases or a whole transmission.

 

 

If your willing to make that drive, you may wish to ask about parts here.

 

Also placing a want add in our classifieds might score you what you need a well.

https://www.wheelhorseforum.com/classifieds/wanted/

Edited June 17 by Achto

[stevasaurus 22,740]

The 1st thing to do is drop the transaxle part of that case, open it up and see what is wrong.  There are some threads with pictures that will help you do that.  A doner case or case half is in order, and maybe some parts.  One of our vendors or maybe one of the members may be able to help you there.  Welding is an option for the case but you need nickel welding rod and do a little at a time so as not to build up too much heat.  Opening the transaxle is not a hard job and the insides are straight forward.  Your horse is worth fixing.  

   Let's see what some others have to say.

Edited June 17 by stevasaurus

[WHX?? 48,815]

2 hours ago, RoadScholar said:

used john Deere or whatever is available

NO ... over our red bodies! 

You don't need anything off the jungle to fix that every thing you need is right here. Parts, manual, expertise, coaching...every thing.  

 

You should have a Sundstrand 90-1136 & heck you was any closer I got three of them for a song & a beer.

Donor cases or a complete unit should be available to the north as Dan said. 

I don't think I would waste the effort on welding. 

Post an ad in wanted never know. 

 

Edited June 17 by WHX??

[ri702bill 8,321]

Was there water in the case that froze???? over the winter?  Acts like a wedge when it expands. The same reason for crushed brass carb floats....

[WHX?? 48,815]

I dunno Bill I've had plenty freeze and not break. I also jack there with no issues. Lucky maybe? 

Open it up can't wreck it. 

[RoadScholar 23]

Heh, sorry about the JD comment... just shows the depth of my depression. The Biglersville meet is about 2 hours away, so that's a possibility, if I can wrestle my schedule into submission.

 

One point of clarification, though:

 

Is the Sundstrand 90-1136 assembly JUST the transaxle, or does it also include the hydrostatic transmission and pump assembly?

[squonk 41,118]

The easiest repair is coming to the show and picking up a complete trans axle. You will find a complete unit is more common than the case. The hydro pump and motor are held on by 4 or 5 bolts with a single gasket. The only thing you will find in the case is the differential assembly with the axles. I think 1 of the differential bolts broke and jammed in the case. 

[Handy Don 12,232]

If you value your time at all, a full transaxle swap is the fastest repair and, as noted above, your timing could not be better for availability.

 

Next would be if you don’t want to trust a new complete transaxle, get one and swap your own pump/motor onto it.

 

I concur with the others that trying to repair what you have will likely take you down a rabbit hole of frustration--especially if the differential has been damaged. And your tractor is definitely worth saving.

 

And probably stop jacking under the transaxle (I put the jack directly under the drawbar at the hitch pin, which takes the load). 🙂

[wallfish 17,000]

Over torquing those NPT plugs can crack the cast. Seen it happen on many engines especially aluminum oil pans. Wonder if that's what started the crack??? They crack just a little bit, then in order to stop the oil leak it gets torqued even harder thinking it's the threads leaking. If that's the case here then the rest of the trans should be good. Picking up a full used trans could just be a swap but you would also have all the good parts and pump of yours to back that up. 

[WHX?? 48,815]

1 hour ago, RoadScholar said:

 

Is the Sundstrand 90-1136 assembly JUST the transaxle, or does it also include the hydrostatic transmission and pump assembly?

I believe it's the whole nine yards. Would have to look at the IPL to be certain. Don't think it was a service assembly in the day. 

 

31 minutes ago, wallfish said:

Over torquing those NPT plugs can crack the cast. 

That's hard to believe on these 'Fish but I'd trust ya with my motorcycle...

[Thor27 767]

The way that cast is pushed out, I'd bet nut come off one of the differential bolts & jammed under bull gear?

edit:  @squonk beat me to it

Edited June 18 by Thor27
add

[oliver2-44 9,751]

2 hours ago, squonk said:

 I think 1 of the differential bolts broke and jammed in the case. 

 

Edited June 18 by oliver2-44

[lynnmor 7,306]

25 minutes ago, Thor27 said:

The way that cast is pushed out, I'd bet nut come off one of the differential bolts & jammed under bull gear?  

Yep, it looks to me like something in there wants out.  You may need more than the case(s), so an entire trans swap is likely the best option.

[daveoman1966 3,752]

My bet--- a differential bolt inside broke off...crashing the differential and a part got jammed between the bull gear and cast iron case.  "Lemme out of here".  In that case, you'll need diff parts too...can't help with that.  However, I can give a couple options: (1) complete transaxle w/out hyd pump & motor $150 (2) right side of trans case $85 or (3) compl transaxle, hyd pump and motor on/from a C-120 Auto $250.  I am in n/w PA...40miles south of Lake Erie.  my email is: daveoman@windstream.net  (if I loose track of this in the forum.) 

[953 nut 55,229]

11 hours ago, RoadScholar said:

Heh, sorry about the JD comment... just shows the depth of my depression. The Biglersville meet is about 2 hours away, so that's a possibility, if I can wrestle my schedule into submission.

 

One point of clarification, though:

 

Is the Sundstrand 90-1136 assembly JUST the transaxle, or does it also include the hydrostatic transmission and pump assembly?

We will forgive the JD comment if you promise not to do it again!

 Since your pump/ transmission unit is good and not giving you any problems I would just buy a used Transaxle and bolt your hydrostatic transmission to it. The Big Show would be your best option to buy one, some times you can pick up an entire tractor minus the engine for less money than just the transaxle.

[RoadScholar 23]

OK, everyone, thanks for the feedback! I've rebuilt a couple of auto engines, but transmissions full of spinny gear thingys give me pause...but with your comments and encouragement, it looks doable, and a trip to Biglersville appears to be in the offing. It does look like a straight-up transaxle swap is the way to go.

 

If nothing comes of that, daveoman1966, I'll be in touch to see what we might be able to work out. I'll be cleaning off my workbench today to get started, and when I have results worth reporting, I'll post them here.

 

At least, with the current heat wave this week, the grass won't be growing too much! Again, many thanks to the Red Square community!

[Pullstart 62,882]

, and I concur with others’ assumption of broken something from the diff wanting out.  See you at the show!

[stevasaurus 22,740]

Here we go...down load the PDF for a breakdown of your transaxle.  The pump and the transaxle are separate numbers...the pump is the Sundstrand  90-1136, the transaxle is Wheel Horse #103903.  When you look at the parts list on page 4, the middle row of numbers is for the #103903 transaxle.  It's an 8 pinion differential with 1 1/8" axles.  

 

 

[Handy Don 12,232]

5 hours ago, RoadScholar said:

OK, everyone, thanks for the feedback! I've rebuilt a couple of auto engines, but transmissions full of spinny gear thingys give me pause...but with your comments and encouragement, it looks doable, and a trip to Biglersville appears to be in the offing. It does look like a straight-up transaxle swap is the way to go.

The thing NOT to do is open up the hydro pump/motor just out of curiosity. These are a definite “keep ‘em full of fluid and if they ain’t broke don’t try to fix ‘em” components.

[RoadScholar 23]

Thanks for the tip, Don, no worries! I aim to do the minimum.

 

Stevasaurus, many thanks for the documents! I actually saw the listing for the file "Tractor 1974 C-120 Auto IPL Wiring Revised.pdf," but I read "Wiring" and kept going as I was looking for transmission info. Only later did I see that I needed to click through the "Download this file" button to see three separate  manuals. All downloaded and all good. Happy to have the wiring diagram also -- about 5 or six years ago I was mowing along when one point in the wiring harness apparently wore through the insulation and shorted to ground. Suddenly I was laying down more smoke than a WWII destroyer! I rewired it all but most of the wires were "black" as in carbonized, so this would be good time to check the replacements out and update to spec if needed.

[stevasaurus 22,740]

Some of these guys are going to be at the Big Show on Thursday.  I suggest getting the transaxle apart and get in touch with @squonk @wallfish @Pullstart @953 nut and let them now what you need...they may be able to find it and have it kept on the side for you.  Don't forget @daveoman1966 for parts he has also.  Save your Horse. 

Edited June 18 by stevasaurus

[RoadScholar 23]

OK, then --- @squonk @wallfish @Pullstart @953 nut, I plan to be there tomorrow morning, probably arriving around 9:30 or so. Not having ever been, I have no idea what to expect/do, other then ask around for you guys and keep my eye out for a transaxle.

 

Road trip!

 

Thanks!

[squonk 41,118]

There is a vendor who parks near the center of the grounds with a big trailer. He probably has one. Look for bins on the trailer. He is on FB and has been advertising transaxles with other parts.

[Pullstart 62,882]

@RoadScholar I’ll be around, look for @Tractorhead’s beautiful flag!  This will be in our EZ Up!