X500/K72 Tuff Torque leak up high---gas tank removal

[al3]

2015 Tuff Torque K72 in a Deere X500 that began to leak transmission fluid; drips on cardboard after mowing. Not a lot; 1 ring the size of a silver dollar or so. After a few cleaning/mow/examine cycles it would appear source of leak is the input shaft seal. Don't know for sure, but its coming from high on the upper case. Have verified the transmission fluid reservoir o-riings/grommet is not the source---too bad, easier fix.

Hoping I could pull the seat/fender assembly/gas tank to gain access to the shaft/drive pulley/fan assembly. Seems like a better approach then removing the entire transaxle.

Anyone remove a gas tank and can report how long it took?

Also thinking I could pull the old seal using the sheet metal screw in the side trick.

Anyone replace the upper seal in a K72 this way with success?



Thanks

 

[tomplum]

The tank removal is pretty quick and easy. There are 2 bolts (13MM heads) on each side that attach the seat platform to the lower body and you will see them underneath at the back of the foot pads. On top the two 10MM headed bolts. Undo the fuel cap and stretch a nitril glove over the outlet to keep dirt out. Unhook the seat switch harness and pull it through the body to lift off. The tank normally will just / lift twist out one it is unhooked. Sometimes the support rest under the neck- like a long bolt has to come out, sometimes not.

It's a great time also to filter your fuel out of the tank and clean things up.

 

[al3]

Appreciate the reply Mr Plum. Sounds pretty straightforward; hopefully will give pretty clear access to the upper case components. Good idea about cleaning the dregs from the tank, too.

 

[al3]

Finally getting to this; good winter project.



Turns out it isn’t the shaft end seal, rather the small (1 3/8 dia or so) rubber plug located on the cases’ top side. (see red pen tip) Rubber is cracked, fluid had the appearance of oozing from the cracks, but at 20 degrees not a lot of oozing to be done, at least quickly. Seems like an odd design for a plug.....

Looked at both JD and Tuff Torque site. From pictures of the replacement parts I’m assuming its a press in? Anyone replace and use either the Deere or TT part and care to evaluate?



Access was indeed pretty straightforward. Bolts/seat switch harness removed as suggested above. For anyone else doing this, you’ll need to unload the drive belt tension by removing its spring. Impact wrench on fan nut will release it and the pulley. Also need to remove two fuel hoses from tank fittings.

 

[tomplum]

That's the official fill plug. It will just pop out with a sharp chisel. Underneath may be a magnet that when lifted out could point to the overall health of your T/A. This would be a great time to change the fluid. Tuff Torq has an updated fluid recommendation. I use 15W50 synthetic, dunno if you you do snow work with this if they still recommend low vis. or not.

 

[dstig1]

You find the part yet?

 

[dadohead]

Use Low Viscosity Hygard for the HST.

One important step in the re-assembly is greasing the input shaft splines! (prolly too late for OP being Sept) The input sheave/shaft joint will 'fret' (micro-motions that create the characteristic red oxides that erode the joint). The factory applies grease to the splines to slow their growth. If not serviced, the input sheave will fret and eventually strip out at about 400 hrs (it is softer than the transaxle shaft). I re-grease this input shaft every 200hrs at the transaxle oil service.... some fretting is present then.

 

[al3]

I’m equal distance (35miles) from two Deere dealers, both had item in stock and picked up yesterday. Need to clean outer cases before removing the old plug.

When disassembling noticed the input pulley had provision to attach a puller (two 180 degree spaced threaded holes) but none was needed. Will take a close look at condition of input shaft teeth, thanks. Unit has about 170 hour.

Interesting design with the expansion tank located above the transmission. Would seem to guarantee a leak/seep if the plug cracks like this one did, at least if the expansion tank is filled above the minimum line. When previously changing the transmission fluid I re filled thru the expansion tank; thus the original plug aged to the point of plastic failure. Looks like that was a bad plan......

 

[Spindifferent]

For future reference, here's another post from a different site regarding the issue:

https://www.mytractorforum.com/threads/x530-transmission-fluid-leak-update.1321515/page-2

I'm bookmarking this thread for my X584 should it ever have the plug leak. I did have to replace the expansion tank as it cracked and then leaked. Not sure to blame Deere or TuffTorque for the poor quality materials...

Good luck with the repair!

 

[dadohead]

I was senior engineer at JD and had responsibility for transaxle before retirement. The K72 was bought complete with overflow bottle and came pre-filled. Tuff Torque owned that design. The K71 before it came without. JD owned the bottle design, installed, and filled the system on the JD line.

BTW- The reservoir provides the necessary pressure head to the pump. From memory, the HST has several internal 'tanks' that are independent of each other. The plugged hole and reservoir hole are used to initially fill the transaxle. This ensures both internal tanks are filled properly before assembly line testing. Hope this helps!

 

[al3]

Thanks for the unique perspective. I grew up on a dairy farm outside of Juneau.


New plug is in, filled. Plug I removed was the early style, all rubber top. With any luck the replacement will hold up longer.


I have a range of grease/lube available to coat the input shaft with; High pressure, low pressure, high and low temp, brake lube, moly assembly lube, anti seize. What would you recommend?

Here's an after shot, nice and clean, non leaking plug (hopefully) installed

 

[tomplum]

Is the misses going to be mad you used her toothbrush? Wow! nice and clean. If you have moly, use it. Most times they have nothing, but I agree it is a good idea.

 

[dadohead]

Wow... practically neighbors!

The line uses JD green polyurea grease. I use that because it's what I have in the gun. I wish there was a better solution. I talked with Tuff Torq about them changing to something like a tapered input shaft (eliminate the micro-motion that creates the fretting). It's a touchy thing though. They own the design and it meets goals so..... can't just call the baby ugly ;<)

Next time mine is off for service, I've thought about trying to install a grease zerk somehow. Giving it a regular grease hit would make it last forever. Prolly couldn't get access to it though. Or something more permanent than grease that would fill the clearances but still allow disassembly? IDK

 

[dadohead]

I'll probably try wheel bearing grease next time... that should stay awhile!

 

[tomplum]

A touch of anything I think is a good idea. Moly is used on splined driveshafts so that's why I brought that up. I don't think lube is even referenced in the service manuals. Interesting that Deere used it on initial assembly. Most don't seem to. TT ships them dry on the K46's I've gotten. The nice thing about an X5 is that the pulley splines don't fail near to the degree as the lighter X3.

 

[tonythec]

Finally getting to this; good winter project.



Turns out it isn’t the shaft end seal, rather the small (1 3/8 dia or so) rubber plug located on the cases’ top side. (see red pen tip) Rubber is cracked, fluid had the appearance of oozing from the cracks, but at 20 degrees not a lot of oozing to be done, at least quickly. Seems like an odd design for a plug.....View attachment 2376126View attachment 2376127View attachment 2376128



Looked at both JD and Tuff Torque site. From pictures of the replacement parts I’m assuming its a press in? Anyone replace and use either the Deere or TT part and care to evaluate?



Access was indeed pretty straightforward. Bolts/seat switch harness removed as suggested above. For anyone else doing this, you’ll need to unload the drive belt tension by removing its spring. Impact wrench on fan nut will release it and the pulley. Also need to remove two fuel hoses from tank fittings.

I have the EXACT same problem. I have removed almost everything but would appreciate any advice if one doesn't own an impact wrench. I am having an issue removing the fan. Any advice is welcomed.

 

[beenthere]

Welcome Tony to TBN

If all you lack is an impact "wrench", then I myself would use this as an excuse to own one. It's how I ended up with a lot of tools.

Tell us more about your situation, and some photos of just where you are at and what is holding you up. Some good assistance may be forthcoming from the knowledgeable members here.

 

[al3]

Way back in college days when I couldn’t afford much of anything and my 1975 RD-350 needed maintenance, I’d use a long handled socket wrench (aka breaker bar) and a rubber hammer as an impact wrench substitute. Trick was to give very firm, hard, raps to the end of the bar to induce the momentary torque on the subject fitting.



Given your X500 output shaft is free to rotate, the rap(s) would have to be quick and forceful. Maybe add a strap wrench to hold the outside of the pulley….. Before going this route review the posts discusses output shaft splines stripping.



As mentioned, a good time to invest in an impact wrench. Inexpensive electric ones at the tool store a lot of folks don’t like are priced in the $40 price range.



Good luck

 

[Richard001]

I have the EXACT same problem. I have removed almost everything but would appreciate any advice if one doesn't own an impact wrench. I am having an issue removing the fan. Any advice is welcomed.

OK this post was not thought out very well. Tony will have to find a way to remove the nut holding the fan/pully on first. Still will need an impact tool.

Then, if the pully is stuck, see below.

On post # 8
al3
Said: When disassembling noticed the input pulley had provision to attach a puller (two 180 degree spaced threaded holes) but none was needed.

If you don't want to purchase an impact gun, you maybe able to use the threaded holes and a gear puller.