TuffTorq K46 Repair Guide with Pictures

[bladesx]

Good day all,

I recently purchased the X300 about two months ago and at this point it has 10.0hrs on the clock. A groaning noise from the transaxle about a week ago prompted me to do an online search for information regarding the transmission.
The results of the search produced a result that I could have never anticipated regarding all of the information available for the K46 transmission.
Taking the suggestions from this thread I removed the unit and poured out the oil. It was black and full of a silvery stream of metal particles as it drained.
Ended up opening the case and installing the drain plugs. Also noticed that the final drive gear train appeared to have been "indifferently" assembled.
Not to be disparaging but the common term, "slapped together" came to mind.
(A bit about my experience, mechanic for 40 yrs specializing in Porsche transmissions).
The motor drive pinion gear slid on the motor shaft to the point where the pinion gear travelled off the end of the shaft by a third of the width of the pinion gear. (There is a friction block that "adjusts" this travel but it would appear that the assembly technician might have made a better selection as opposed to the one that was installed).
A shim for the friction block set the max outboard travel of this gear to coincide with the length of the shaft thereby limiting the uncontrolled slide of the pinion gear on the motor shaft so that the gear remains fully engaged on the spline of the motor shaft.
Observation of the initial position of this pinion gear relative to the "intermediate" gear was such that during max axial travel of these gears sliding to and fro in this uncontrolled fashion on their respective shafts produced a contact between the motor pinion gear and the intermediate gear such that only half the width of the gear teeth were engaged. I believe that this cannot be by design or then why would the engineer designer not have installed a gear half the width?
A stainless steel intermediate gearshaft shim was fabricated on the milling machine with a final fitting dimension achieved by a few minutes on the surface grinder. The intermediate gear then itself required a shim since the gear had ~1/4" travel back and forth on the shaft.
Careless production line quality or is this the standard of the fitting of precision gears in the lawnmower industry ?
The quality of the gears and shafts themselves appeared to be of a good order.

The large differential gear at its outboard circumference had a "wobble" that allowed the outer circumference of the gear to travel in a arc that was
on the order of 3/8". A strategically placed shim on the final driveshaft had the combined effect of bringing the "spider" gears into full contact and alignment along with the support of the differential gear itself on the driveshaft effectively removing the "wobble" of the gear and the excessive end play travel.
All shaft/shim clearances were adjusted to .020".


In the end the question might be, would the metal that is ultimately found over time in the oil that fouls the hydrostatic pumps be produced by excessive mechanical wear aggravated by the poor fitting of the final drive gear assembly?
(Taking into account the break in period where good mechanical practice would suggest that the oil be changed out within a short period of time from new to remove the initial accumulation of metal. )
With the excessive shaft end clearances which allow the gears to travel out of full contact and alignment with one another along with the degree of axial movement of what should be precision fitted parts the wear of these parts must be accelerated thereby loading the oil with particulate matter.
1st photo, Black oil full of metal
2nd photo, Metal fuzz on one of the magnets, 10.0hrs of run time since new, all of the other magnets held equal metal or more
3rd photo, Stainless steel shims, properly selected factory shims during assembly would not have required this additional work although
it would require the factory to train the assembly people to a higher degree and it would also require additional instrumentation,
tooling and time on the assembly line.
4th photo, Pinion gear to intermediate gear, full contact now
5th photo, Intermediate gear inside shim, the intermediate gear was allowed, by factory assembly, to travel along the intermediate shaft ~1/4"
for no apparent reason. One could see that under changing conditions of loading that this gear could conceivably, "slap" back and forth between
the factory shim and the shaft collar, (the shaft collar then with this amount of available travel would be slapped into the side of the differential
gear by the travel of the intermediate gear).

The oil will be 15-50 AMSOIL

Without disrespect, due to the fact that we are fortunate to have access to an automotive repair shop with an attached machine shop section we have no direct need for the factory warranty.
Also there will most certainly be many that will claim that this is, "the way the factory wants this".
In the many years of my occupation in this type of work I have not observed a factory that produced a quality product with this approach to an assembly technique.
It will take some convincing that this [poor] level of assembly is by intentional design as opposed to the pressures of expeditious production methods to reduce per unit cost.
It may be not too difficult to understand how such a fundamentally sophisticated unit should only be expected to last 250hrs when it is assembled in this fashion.
View attachment 318770View attachment 318771View attachment 318772View attachment 318773View attachment 318774
No work was performed on the hydrostatic portion of the unit. Fresh oil and a good cleaning will hopefully remove the pump noise.

Thanks to all that have added to the body of knowledge regarding these units.
andrew

Very likely chi-com sourced parts- unbelievable lack of standards or adherence to them. Recently had a customer with a large number of pieces from that area that had to be remachined, fortunately they were oversized for the most part. I was able to save 80% of them.

 

[bladesx]

The clip for the free wheel rod was gone, I wonder if that rod was lifting up enough to contact the blades.....?

Yes several pages back another had the same problem, broken retainer clip on rod.

 

[motorcity]

Yes its a K46 BT model, out of an Ariens (AYP Made) tractor. The disc's aren't even shown on any of the exploded view's for this model on Tuff Torq's website. I emailed the cutomer service, with pictures.

 

[scottxxsmith]

Help! I've just finished rebuilding my K46AC. It made a "pop" a few days ago and quit. Hadn't been losing power or anything. I found lotsofgreengrass's write up and decided to give rebuilding a try. When I took my tranny apart I found that the differential gears were trashed. Teeth sheared off and the transmission full of metal particles. I cleaned everything out, replaced the differential gears, put in the cylinder block motor and pump kits (per lotsofgreengrass's instructions) and a new filter. Filled it with 5W50, fired it up, and nothing. I've done the air bleeding procedure until I'm about crazy. I've gotten the tractor to run a "little". It will sometimes run but with a very loud groaning sound. Then it will stop completely. I can do the air bleeding thing again and it might run for a little while, then stop again. When I do get it to run it goes OK in forward, but when I try reverse it will go at only 1/2 pedal depression, if I push the pedal all the way down it stops. Weird...I'm at a loss as to what the problem might be. Anybody got any suggestions? I'd tear the thing apart again but don't know what to look for.

I'm having similar problem replaced the suggested parts put it back together and all i get is a groaning sound. Tore it back apart several times checking the pin, washer, fluid level. I didn't cahnge the center block could this be my problem?

 

[motorcity]

@motorcity:
Sorry to ask, but are you sure this is a K46? I've never seen those parts on pictures, nor on diagrams, parts list and not in my K46(AM).

They are shims that go in the little piston's on the pump & motor. They shims go in, them the springs, then you install the pistons in the motor.

 

[pooleo]

Any one have thoughts on the K61? Have a chance to snag one for $150. I am ok with slight modifications to make it work. But not interested in completely re-routing the linkages and stuff.

 

[60DRB]

Just found this site.

I've got a '04 JD L118 with over 580 hours on it. I'm currently waiting for drive idler wheels to arrive, and meanwhile discovered this good info on how to extend the transmission/mower's life. It's been a little whiney for a few years, but still working on my hillside two acre yard. I guess I'll be ordering the internals for the next rainy weekend repair job.

 

[60DRB]

Just found this site.

I've got a '04 JD L118 with over 580 hours on it. I'm currently waiting for drive idler wheels to arrive, and meanwhile discovered this good info on how to extend the transmission/mower's life. It's been a little whiney for a few years, but still working on my hillside two acre yard. I guess I'll be ordering the internals for the next rainy weekend repair job.

 

[pooleo]

Welp, I picked up the LX176 rear end today. The guy also threw in the complete chassis. Its a little different animal but with having the belt and all the linkages, I should be ok. Thinking I might just cut the frame off and weld to mine......? idk yet.

 

[pooleo]

Working on my swap. For the L120, the K61 needs to be dropped about 2". The fan will hit the frame rail and the right fuel tank support. I ended up cutting the OEM mounting points from the frame. Cut the same piece off the donor frame. Going to position and weld in place.