Export thread

I have posted previously and had some great advice from Bertsmobile1 and Rivets. The mower was sluggish, so decided to drain and replace the oil to see if that would help. On replacement I had advice on how to purge the system and after a while I managed to get forward and reverse motion from the elevated wheels. I had an issue on how to check and top up the oil. So decided to cut a disc with a hole cutter next to the seat and forward of the fuel tank, This allowed a much easier view of the port for checking the oil level and with a tube located in the hole and up through the hole I cut next to the seat, made it really easy to top up. I then dropped the mower and tried it for drive. It moves forward and back and will also cut the grass, but I am not convinced it is has the same pulling power as it should. I tried to navigate up a 30 deg slope and it would complete. When I took my foot off the forward drive the mower rolled back but very slowly, so not sure if this is helpful to determine the state of the Tuff Torg K51. If The feeling is I need to try and service the unit, has anybody an idea of were best to buy a K51 repair/service kit, as looking on line some of the prices are too expensive to warrant servicing the unit. Any help would be really appreciated. Terry

The tranny is well worn and on it's way to the grave
Lots of videos showing how they actually work on that place .
If it just does not have enough balls you can replace the oil with a heavier grade
JD usually used 10W40 or 10W 50 and you can get a few more seasons out of one by filling with 20W 50 or 20W 60
I have one currently running on Harley oil 50w 75 for a pensioner who does not want to get his tranny fixed .
Once the valve plate is scored it just gets worse over time so the heavier oil can not make what is broken any worse
Down side is the heavier oil is a lot harder to purge the air out of
You can use thicker oil but do not put any of the oil fortifiers ( Lucas etc ) in there as they stop the pump from working properly .

bertsmobile1 said:

The tranny is well worn and on it's way to the grave
Lots of videos showing how they actually work on that place .
If it just does not have enough balls you can replace the oil with a heavier grade
JD usually used 10W40 or 10W 50 and you can get a few more seasons out of one by filling with 20W 50 or 20W 60
I have one currently running on Harley oil 50w 75 for a pensioner who does not want to get his tranny fixed .
Once the valve plate is scored it just gets worse over time so the heavier oil can not make what is broken any worse
Down side is the heavier oil is a lot harder to purge the air out of
You can use thicker oil but do not put any of the oil fortifiers ( Lucas etc ) in there as they stop the pump from working properly .

Click to expand...

Thanks for that reply. When you say heavier oil, is it just any synthetic oil of the heavy grades or are specefic ones for hydrostatic transmissions? Thanks, Terry

JBASport said:

Thanks for that reply. When you say heavier oil, is it just any synthetic oil of the heavy grades or are specefic ones for hydrostatic transmissions? Thanks, Terry

Click to expand...

Exactly what I said heavier = thicker
If the box has gone a synthetic will not help and you will not find synthetics in most of those weights
First number is the viscosity of the base oil .

bertsmobile1 said:

Exactly what I said heavier = thicker
If the box has gone a synthetic will not help and you will not find synthetics in most of those weights
First number is the viscosity of the base oil .

Click to expand...

Thanks, understood. I have also noticed that one guy suggested using fine wet and dry to reface the pump mating surfaces. I thought that might be worth a try, what do you think? Thanks, Terry

Because parts are expensive down here I have a machining shop that resurfaces both the piston chest and the valve plate then he shims up the two piston chests to provide the correct clearances
This is a tricky job because the mating surfaces are not smooth, they require a specific level of roughness to encourage the the oil to pass through the pistons rather than escape out the sides while enough escapes down the sides to keep everything lubricated
On top of that the surface has to be machined like an LP record except the spiral goes in towards the centre like an oil slinger from the days when engines & gearboxes had no oil seals
It is about 1 hr to remove the transmission, 0.5 hr to clean the outside & dry it 1.5 hrs to split the box & clean off all of the silicon then the same time to replace everything
So do you want to do all of that then find it is no better than when you started , or does not work at all ?
Choice is yours naturally
And then there is the running clearances and making good for the amount of material removed
I am a reasonable machinist & have access to lathes, mills & shapers but it is a job I decided was not worth my effort
The drop in pump-motor units are not all that expensive

bertsmobile1 said:

Because parts are expensive down here I have a machining shop that resurfaces both the piston chest and the valve plate then he shims up the two piston chests to provide the correct clearances
This is a tricky job because the mating surfaces are not smooth, they require a specific level of roughness to encourage the the oil to pass through the pistons rather than escape out the sides while enough escapes down the sides to keep everything lubricated
On top of that the surface has to be machined like an LP record except the spiral goes in towards the centre like an oil slinger from the days when engines & gearboxes had no oil seals
It is about 1 hr to remove the transmission, 0.5 hr to clean the outside & dry it 1.5 hrs to split the box & clean off all of the silicon then the same time to replace everything
So do you want to do all of that then find it is no better than when you started , or does not work at all ?
Choice is yours naturally
And then there is the running clearances and making good for the amount of material removed
I am a reasonable machinist & have access to lathes, mills & shapers but it is a job I decided was not worth my effort
The drop in pump-motor units are not all that expensive

Click to expand...

Understood. I would gladly replace the pump unit for my K51b but all the prices I have seen sem to be way out of a realistic price range. Maybe you have an idea where best for me to try and buy one? Thanks again for your help its really appreciated and apologise for being a nuisance. Terry

Lets take it from the top Terry
Roughly where on this big wide world are you ?
In the USA apparently the units are very cheap from Mulligans
In OZ they are $ 600 to $ 800 wholesale so that is around a grand to the customer + fitting
A new trans will go around the $ 2000 mark down here .
Apparently UK prices are even higher .

I am in Scotland (UK). I was hoping someone in the US might have come in with a suggestion, as if they are that much cheaper the shipping cost wouldn't be that dear I suspect. Cheers, Terry

Link is there in my post, the word "Mulligans"

Thanks for that. Terry

Those units are known to strip the splined input shaft. Could that be part of the issue? I have a Sabre that happened to. Haven't had time to repair it yet.

Thanks. I have checked that. It appears the pump faces are the issue allowing oil to pass when it shouldn't. Consequently losing power. Rebuild needed I fear.

Way back in post 2 you got a plan
Pull it off remove the fill /drain cap carefully
Tip upside down for 24 hrs to drain most of the oil out
Refil with a heavier, thicker engine oil, even a cheap supermarket 25W 60 should give you a couple more seasons for £ 20
SO then you should have 3 years to decide what to do
Note the heavy oil is the proverbial banana skins in a noisy diff bodge that would do Arthur Daily proud but usually works for 2 to 5 years and the parts are already throw away condition

bertsmobile1 said:

Way back in post 2 you got a plan
Pull it off remove the fill /drain cap carefully
Tip upside down for 24 hrs to drain most of the oil out
Refil with a heavier, thicker engine oil, even a cheap supermarket 25W 60 should give you a couple more seasons for £ 20
SO then you should have 3 years to decide what to do
Note the heavy oil is the proverbial banana skins in a noisy diff bodge that would do Arthur Daily proud but usually works for 2 to 5 years and the parts are already throw away condition

Click to expand...

Thanks for that Bert. Take care, Terry

Hey Terry, I would pull 16oz out of it and pour a bottle of Lucas transmission stuff in there, that's about all you can do at this point. There is a guy on here somewhere that you can send the parts to and he rebuilds it and sends it back. He may be on ebay too, but it's a 100 bucks. It could be youtube I saw him on too. Here in Texas you can buy a complete mower for 200 bucks with a bad motor and yank the tranny

Hugeroost said:

Hey Terry, I would pull 16oz out of it and pour a bottle of Lucas transmission stuff in there, that's about all you can do at this point. There is a guy on here somewhere that you can send the parts to and he rebuilds it and sends it back. He may be on ebay too, but it's a 100 bucks. It could be youtube I saw him on too. Here in Texas you can buy a complete mower for 200 bucks with a bad motor and yank the tranny

Click to expand...

Thanks for that. Yes you are lucky to be in Texas, everything costs a fortune over here!

I decided to take the cover off the Tuff Torq K51 to check the filter. However after previously draining the the unit by removing the plug and turning upside down and letting it drain fully over 2 days. I then refilled it with Triax Trans Zero 20w 50. I purged it and ran it around the grass for about an hour. It was still hesitate, so decided to remove it, drain it and split the housing so I could check the filter. However the oil came out very cloudy, like it was emulsified. Which I fould strange as it had only had about an hours running. The oil I used can be seen in the foil cup in the images, totally different to that in the tray and in the filter, again in the pictures. I am going to replace the filter and refill, but worried the oil might do the same. I welcome advice on what could be the problem? Thanks, Terry

You need to use ENGINE OIL not transmission oil which has a high film strength so bubbles created will take a very long time to pop
I did mention what to use

JBASport said:

I decided to take the cover off the Tuff Torq K51 to check the filter. However after previously draining the the unit by removing the plug and turning upside down and letting it drain fully over 2 days. I then refilled it with Triax Trans Zero 20w 50. I purged it and ran it around the grass for about an hour. It was still hesitate, so decided to remove it, drain it and split the housing so I could check the filter. However the oil came out very cloudy, like it was emulsified. Which I fould strange as it had only had about an hours running. The oil I used can be seen in the foil cup in the images, totally different to that in the tray and in the filter, again in the pictures. I am going to replace the filter and refill, but worried the oil might do the same. I welcome advice on what could be the problem? Thanks, Terry

Click to expand...

In USA, From Gardner, my cost, Rebuilt a few with good luck. Pay attention to that pin!! Good Luck!

I wish it was that cheap here! Thanks for the support. Cheers, Terry