Conquest K66 oil change - - The Friendliest Tractor Forum and Best Place for Tractor Information
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post #1 of 6 Old 07-16-2012, 09:45 PM Thread Starter
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Conquest K66 oil change

I have searched for a guide on doing the oil in my trans for a while and I just cannot seem to find one. Actualy, I have found the tuff torque one for the axle if it was not in a tractor, but no one seems to have any information on how to do the task while it is still in the machine. Has anyone done this, or should I be taking notes and photos?
Any help is appreciated!


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post #2 of 6 Old 07-17-2012, 09:21 PM
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Re: Conquest K66 oil change

I think the hydrostat in the Conquest is supposedly "sealed" like everything else is today *rolls eyes

I don't think it'd be difficult to drill and tap a hole (be sure to get a plug!) in the bottom of the transmission (the tranny oil will flush any shavings out the bottom), and I think they have a fill plug on top.

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post #3 of 6 Old 07-18-2012, 09:14 AM Thread Starter
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Re: Conquest K66 oil change

After searching I decided to go ahead and just do it. Below is my write up of the procedure. I would assume it would be roughly the same for the Prestige or Broadmoor, but with a different axle at the end.

K-66L Transmission Oil Change on Simplicity Conquest Model 1694011

First off, Simplicity lists the unit as “sealed” and Tuff Torque says it’s serviceable and recommends that the oil be changed after the first 50 hours and every 200 thereafter. Whom you want to believe is up to you, but I saw drain plugs, fill plugs, and an expansion “overflow” bottle that said to me “serviceable”.
I tried to photograph as much as possible, but in some cases it just wasn’t feasible without a dedicated helper, which I do not have, sorry, I did what I could with what I had available. I should also clarify that this document is more on how to get to the axle and not so much the axle itself. The Tuff Torque documentation is excellent and is real easy for locating the drain bolts and the filling procedure.

Here’s a short list of things that will be helpful if you plan on undertaking this task;
• Download and read the procedure from the Tuff Torque Website (updated to correct file, should mention "Expansion Reservoir")
• Make sure the gas tank is close to empty.
• Have a bucket ready for slop that’s packed in-between assemblies.

1st thing I did was take the rear hitch plate off. In the end this step was not necessary, but made checking the oil level after a run easier for me and it was only four bolts. (The flat-two connector in this photo is for a sprayer and is not “factory”. It may show up in other pictures, but don’t fret if you do not have one.)
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Surprise #1 - Another smaller hitch lives under the big hitch.

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Second step was to remove the seat. Four bolts and an electrical connector had to come out. It looked like if the seat would have slid forward a touch more it would have lined up with the fender deck bolts and negated having to take off the seat. Check yours before removing the seat. However, even if the seat stays on the fender deck, you’ll need to disconnect the dead man switch electrical connector.
Step three; there are six bolts that hold the fender deck to the frame. Two under the seat, and two through the floor pan, frame, and fender deck on each side. The two under the seat go into welded bolts, the four under the floor pan use nuts that will most likely be packed in dirt and grime. Once those bolts are removed, use a torx driver on the cruise control handle and unscrew the gas cap…

Step four; remove the fender deck. Those grab handles work exceptionally well and the weight is very balanced. You’ll want to be careful with the electrical connector as it passes through the hole in the deck.
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The black sludge on the gas tank is grass from the previous owner on its way to a new form of life!

Step five
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The slime on the gas tank is messy, but after a little clean up things will move right along.(Mid right is the power for the sprayer and is not on other units.)
Here you’ll want to remove the two leads for the fuel gauge and the fuel line at the tank. Make a note of which wire goes where, it will be important later if you like your gauge to work!
Once that is done, the tank will lift up and slide to the rear and come out with no fasteners. Find a level place to stash it until it’s time to reassemble.
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Rear View
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Top down view from where the gas tank sat. (Note the fuel line to the left)

This brings us to step six. The gear side is completely accessible, but the hydro side is still blocked. I took off the fan portion, but that was unnecessary as it was only bolted to the pulley and not any other component. I used a mini-impact to get the nut off the spindle and once that came off the pulley just slid it up off the axle and I could get to the hydro side with no issues. (I should note that I attempted this with a standard ratchet and it just spun the axle, if you do not have a mini-impact (1/4" drive) you will need a way of holding the axle stationary when loosing the nut)
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Step seven. Drain the oil from each side of the axle using the service guide’s drain plug locations.
You can also fill it using the same guide as access to all the ports are now available.
In filling the axle’s hydro side you have to remove the expansion tank, and when doing so I recommend draining and cleaning it at that time as well.
Mine has 400 hours on it and I have no idea if the oil was original or not, but I know it didn’t look much like the oil that I put into it! After doing this oil change I am happy that I did it because A) it wasn’t that big a task B) good oil is cheap insurance C) a few hours in the garage with tools is after all… fun!
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Things I learned;
The K66 has a charge pump on it so purging air from it goes much fasted then on the smaller axles. I ran it at low throttle and it hesitated for about one second then ran like normal. I throttled it up and ran it around the yard and then checked the oil level again. The procedure of placing it on jack stands until the wheels start to move would be a huge waste of time, IMHO.
One of the connectors to the fuel gauge sender broke on removal. I easily replaced it as it was a standard connector.
The black "access ports" in the fender deck are more of a pain then removing the whole deck.
This is an excellent time to clean the nooks and crannies of the axle casing.
This is also an excellent time to run (or rerun) power to the back for either sprayers or lights.

Hopefully this proves useful to someone out there who wants to undertake this, in hindsight, simple task.


Last edited by drbrian722; 07-18-2012 at 09:32 AM. Reason: linked to wrong document
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post #4 of 6 Old 07-18-2012, 05:15 PM
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Re: Conquest K66 oil change

Hi drbrian722,
I just saw this, or I would have chimed in earlier. I changed the oil in my K66L without removing the deck. Draining is easy, it's the filling that's tough. I used an oil suction gun to refill the hydro. It took a while; fill some and wait for it to settle, fill some more, repeat.
I was going to remove the deck, but it seemed like more work to me, but next time I'll try it that way to compare.
I believed Simplicity's line that the hydro was sealed, and didn't find TT's web site until I had 150 hours on mine. The oil that came out was clear, but there were a lot of small, dark bits that looked like clutch lining. I have no idea what they were, since there are no clutches that I know of in the hydro.
Good article, thanks for posting!

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post #5 of 6 Old 04-27-2013, 01:37 AM
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Re: Conquest K66 oil change

Just performed the fluid change using Brian's method - Thanks Brian! On my 2002 Conquest, the seat slid forward enough to get to the two bolts for the deck so I did not have to take the seat off. There were actually cutouts in the seat bracket that appeared to be just for that reason. So check for that first before removing the seat, most likely changed per year.

My tractor had right around 250 hours on it and the fluid was definitely due. It was clean,however did have a hint of moisture (no water but the fluid did look a little milky). For those of you who haven't changed it yet, I would definitely do it.

While I had it apart I also changed the drive belt. Very glad I did since it was a lot easier to mount PTO pulley with the belt slack and mount the tranny pulley last. It's a heck of a lot easier to line up splines (tranny pulley) than it is to line up the key (PTO). So my advice is to check the belt and if close to due, do it while it's easier.

Other learnings:
Don't have the gas cap on when removing the tank. I don't know if my vent is screwed up, but any pressure on the tank would force gas out the now open pick-up barb (the fuel line was off at this time) obviously. Leaving the cap off obviously allowed any pressure out.

Use a shop vac! Any time I am taking apart a lubed unit of any kind, I always have a shop vac running to make sure any contaminants get sucked up instead of accidentally entering the unit (use a crevice attachment and hold near the fill cap and reservoir when removing because there will be a bunch of grass/sand present even if the unit was blown off with a compressor). I also vacuumed everything off while using compressed air before that.

Other than that, pretty dirty job (from the lawn remnant in every nook) but pretty straight forward.
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post #6 of 6 Old 04-27-2013, 10:48 AM
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Re: Conquest K66 oil change

I followed these instructions when I changed my fluid. It should be the same with the exception of the front axle.
Attached Files
File Type: pdf K664C + KXH10N Oil Draining & Filling Procedure (2).pdf (370.5 KB, 760 views)
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