With the bolt out of the gears, I can look into the differential and see both 'spider' gears. The axles turn freely if a little sloppy without the bolt in place. The broken bolt easily slips back into place through both 'spider' gears and the broken edge of the bolt is flush with the outside of the gear (there is part of one thread still visible on the bolt). This assembly has maybe 1/2" clearance around it from the aluminum case.

So, from what mownie tells me, it makes sense then that as there is power being driven through these 'spider' gears, and because they are beveled, I would assume that the bolt is there to hold them together, opposing the force that drives them apart. I can see that all those jack rabbit starts could weaken the bolt and shear it right off eventually. I don't want to fix the symptom, I'm looking to fix the problem here and I think this was the problem.
So, can I just take a hardware store bolt, 1/2" diameter, stick it in there with a couple washers, grind it down so it clears the case and I'm good to go? Or would a stainless steel bolt be stronger?
fwiw, I stopped at a service center today and they didn't have any parts available from MTD for this or any better suggestions than a hardware store bolt.

A grade 8 bolt is the only grade of bolt to use if going with SAE (fractional sizes) bolt/nut.
If going with metric bolt/nut, use only grade 10.9.
Stainless Steel does not mean superior strength, only corrosion resistance.

Thanks, that's good advice.

I picked up a grade 8 bolt that was too long. I sawed it off to the right length and it fits right in. I'm still working on reinforcing the broken aluminum casing. I ordered some Shell grease type 0 from mcmaster carr $6 for 14oz. This weekend I'll try to get it together.

Here's a photo of my blown out transmission that occurred while I was test driving it.

I JB welded the large parts back together. Then I JB welded strips of aluminum sheet over top. Then I reinforced inside and out with fiberglass sheet and resin.

The bolt that holds the differential gears together snapped at the threads. I used a hardware store grade 8 1/2" bolt 4 1/2" long. I have access to a lathe at work so I machined the head and nut down to the same thickness as the head of the bolt that came out of the machine. I never found the nut that came off or the washer that must have been there. I had one existing washer that I replicated for the other side, I made it out of brass because that was what I had available. This washer and the other one are pressed into the steel housing for the differential until they contact the free-floating gears. I locktited the nut on.

This shows the Shell gladus type 0.5 grease in a bowl. I was concerned I didn't have enough and that it was still too thick so I mixed it with 2 or 3 ounces of gear oil 95w140 with a hex wrench in a drill. No Peerless Bentonite! I'm still not entirely convinced that Peerless made these transmissions.
I packed about 16 or 17 ounces of grease into the box and bolted it up.

I put it back on the machine and took it for a spin. The transmission worked perfectly and everything held together fine, I ran around the neighborhood testing it out for at least a half hour, no leaks or anything. I don't know how long it will hold up, we'll see.

I put a new electrical connector on the anti afterfire solenoid and the machine no longer stalls out so it appears that there was a bad connection there. I suspect that the shop who 'fixed' this machine was searching for a bad safety switch or other electrical problem and opted to remove all safety switches and wiring instead!

"No Peerless Bentonite! I'm still not entirely convinced that Peerless made these transmissions."

I'm not aware of any other brand that used Bentonite grease.

Maybe someone else is???

Good photos to go with everything.
Hey......the missing nut and washer.........are probably out in the grass somewhere when the trans case blew open. The damaged case looks like something got between the differential carrier assembly and the case and whammo!
You turned out to be a capable person.
When you opened your thread, well.....I groaned a little :^)
But it's all good now.

I searched the yard with my friend and we combed through it. I hadn't driven the tractor very far, just a big circle. I can't believe I can't find it, oh well.

I'm sure that when the threaded part with the nut busted off it jammed in between the differential housing and the aluminum case and busted it open, I could see the marks in the case. Also, the first photo shows that there wasn't really much grease in there, there wasn't any on the ground where all the aluminum bits were. when I packed it back together, there was way more grease that I put in then I took out.

Thanks for the compliment. I might add that this will be the first tractor I have owned and worked on too!

Ok, bill_kapaun, I will certainly defer to your expertise on the matter of whether this is a peerless transmission. I went on the peerless website and downloaded their pdf manuals on all their transmissions. None of them were exactly like mine but some were very close. I think it's a safe bet.

I too groaned a little when I read your thread title. You have mastered the next level of your training -- soon you will be an MTD-JEDI.

These Peerless transaxles can fail in some really entertaining ways. I must say I've never seen a housing fragment like yours did, and cudos to you on the great job with JB Weld. You can often score a used housing on Ebay, should the need arise.

My own transaxle was eating itself, slowly. The long side axle shaft had eaten thru its bearing, and was in the process of sawing through the housing. I always wondered how the back wheels were taking on a certain positive camber (like an old VW Dune Buggy). And then one day the tranny locked up solid, and I had to drag the mower in from the pasture.

Found out the reverse gear had siezed on the intermediate shaft (pic of mine attached below). You can actually get internal parts for these trannys from the internet. They can be rebuilt. I see from your picture you're doing the right thing with lots of grease. This, plus keep the loads light and the speeds low on these trannys, will help them live.

I made it through the end of last season with no leaks and working fine. I'm about to pull it out of storage and get it ready for another season. Hopefully it will hold up! I'm thinking about a pull behind trailer/leaf vacuum project this summer.

Fingers crossed here :^)

Jim,

We all wish you the very best of luck on this! I don't know of anyone else who has grenaded the tranny housing, and then made such a skillful repair on it.

Caution should be used when considering pulling any kind of trailer implement with this class of mower. Yes, they can pull fert spreaders, aerators, and light trailers, but keep in mind these transaxles are operating close to their limits just pushing along the mower and our (sometimes) big butts.

For those who haven't yet had the pleasure of tearing into their Peerless transaxles, below is a diagram which shows the top end parts not shown in the previous pictures.

The Input Shaft is driven by the big pulley on top of the outside It drives a Pinion Gear, which is in constant mesh with both the Forward and Reverse gears. The Fwd and Rev gears are free-spinning on the Intermediate Shaft, so they constantly spin in opposite directions from each other.

Between them is the little Shifter Shuttle, which is splined onto the Intermediate Shaft. When the F-N-R shift lever is in Neutral, the Shuttle sits right between the FWD/REV gears, and not meshed with either one.

When you shift into FWD or REV, the Shuttle is pushed into mesh with the FWD or REV gear via those triangle dog teeth. The Shuttle splines then drive the Intermediate Shaft, which drives the Differential unit, and away you go.

What's important to note here, is that when you're moving along in normal forward motion, that Reverse Gear is actually spinning against the Intermediate Shaft at 2x normal speed -- it's being driven in reverse at normal speed by the pinion gear, and the Intermediate Shaft is turning under it at normal speed foward.

What this means is, if your tranny gets low on lube grease, this Reverse Gear bushing is probably gonna be the first part to die (due to the 2x speed). So, keep the lube good, keep the speeds and loads low, and the tranny will live.

I know this post is old, but Google felt it was relative to my question. I'm having a problem with the transaxle designed pictured in the drawing and photo shown above.

The symptom was the Mower stopped forward motion, and belt was smoking. I replaced the symptom first (a new drive belt) and continued with my unsuccessful diagnosis. I removed the transaxle and watched a half dozen videos of what's going on inside these little buggers. What I found was the reverse gear was wobbleing excessively on the shaft and hitting the bolt and nut that goes through the differential or spider gear carrier and jamming up, stopping the Mower dead in its tracks.

I scored a deal on both gears, the shaft and shifter finger on EBay. It arrived but was a right hand shift model. I own a left hand shift. So I could not use the new shaft for the forward and reverse gears, I had to clean up the old shaft best as possible,, it appears ok, but I understand it runs constantly at twice the speed. It maybe on borrowed time. (Trade a right for a left shift axle anyone?)

With the transaxle still open and split in half, I drove myself nuts trying to figure out what kept the reverse gear all the way over to one side, as even the new reverse gear ran into the diff bolt. Your above drawing and hand written explication cleared this up for me, THANK YOU! the pinion gear lines all that up and keeps the reverse gear from traveling too far and running into the diff carrier bolt.

I discovered all this sitting in the comfort of my Lazyboy while searching on my tablet. As of this moment it's all theory, the transaxle sits open on my workbench out in my cold garage tonight. I will tackle this problem tomorrow, and if it doesn't go well, I will check back here and I'll include pictures, they seem to be the key to some excellent responses. If you guys have picked up on something in my post that is a red flag in my repair that I've gotten wrong or I don't see, please I'm all ears gentleman. Thanks for your time.