C-161 w/Sundstrand Won't Move

[mattd860 162]

I went to use my restored 1979 C-161 with Sundstrand Transmission today but after starting it up, the tractor would not move. It has been sitting outside for the past few days so I figured the oil was cold so I let it warm up for 30 minutes on medium throttle. But even after the warm up, there was no forwards, reverse, or lift cylinder engagement. If moved the lever all the way forwards and pushed the tractor about 3 feet, then the tractor will move forwards but feels week. Still, reverse and the lift cylinder would not work. As soon as I stopped the tractor, I would have to push it again for it to start working again.

I drove it into the garage and starting investigating but didn't see anything externally wrong. The belt is still tight, the tow valve is closed, and the oil level on the dip stick is perfect. The transmission pump is warm, however, the transaxle and the oil filter are cold indicating that oil may not be circulating. There is a very slight leak on the right axle but not even enough to drip out on the floor.

I just restored the tractor in September and have not even put 1 hr on it since then. Since I bought the tractor with a blown motor and I had no idea if the transmission was good or not, I did put cheap 10w-30 oil and a standard engine filter on it but again, I haven't even driven it for an hour and have every intention to swap the oil for synthetic 10w-30 and the proper filter. Nevertheless, I hope I didn't screw something up by ever-so-quickly using the wrong filter.

The last time I used the tractor was last Sunday morning where I all I did was move it out of the shed so I could clean it out. Last Sunday was like 25 degrees outside and I didn't even have to let the tractor warm up. Today the temps were about 45 degrees.

I hate problems like this because it literally broke while just sitting there doing nothing. I drove the tractor just fine on Sunday, turned it off, then restarted it today and somehow between now and then it broke!!!

Any suggestions???

[Wheelhorse84 87]

New wheelhorse filter maybe?

[Sparky-(Admin) 21,411]

I think the TORO/WH filter has something different than an oil filter for your car. A bypass or something like that. Get that filter off it. Just my opinion.

Mike.........

[midnight rambler 36]

hey if you need a sunstrand pump and if a 16 auto pump is the same, i will sell you one. send me a pm if your interested.

[stevebo-(Moderator) 8,351]

Matt,

You may have a small partical of debris holding the ball in the hydro valve open. I have the manual for that tranny if you need it send me a pm with your email.

[truckin88 104]

hydro filters do not have bypass valves, napa, and other auto supply houses sell the correct hydro tranny filter....looks like an engine filter but is not. I would use the toro filter first, napa if the dealer is far.

[mattd860 162]

I'm willing to bet some gunk got past the filter because the bypass valve was open.

If the transmission doesn't work now, how will changing the filter make a difference?

[WheelHorseSteve 56]

Hey Matt --

I had something very similar happen to me about a year ago with my Sundstrand equipped C-160. It was running a WH filter at the time and something internal happened and caused my tractor to come to a standstill... no warning, no resolve. I took off that transmission and retrofit one from a Charger... which knock on wood is running great. Eventually I plan on tearing apart that hydro pump and motor and trying to figure out what might be wrong. There is a service manual available for these that will walk you through the diagnosis process... there are a number of valves (acceleration valve, etc.) that could certainly be the culprit as SteveBo was suggesting.

The Electros, Chargers and "Horses with No Name" run a hydrogear-driven Sundstrand which is somewhat different than the piston-to-piston Sundstrand that the C-series came with. Beyond that, the C-1x1 tractors have a version of the Sunstrand that supports the brake band -- with an additional shaft coming out the side for that drum to attach to. Thus, you're really going to need to find another one from a C-1x1 tractor to be able to leverage that brake. If you're not so concerned about that and can get your hands on one of the older Sundstrand trannys I can walk you through the differences.

Sorry to hear about your hydro! I hope you can get it running again soon. This is precisely why one WH is never enough!

Edited November 23, 2012 by WheelHorseSteve

[squonk 41,363]

hydro filters do not have bypass valves, napa, and other auto supply houses sell the correct hydro tranny filter....looks like an engine filter but is not. I would use the toro filter first, napa if the dealer is far.

Napa (Wix) 1410 hydraulic fluid power filter. I have a complete tranny/transaxle sitting in my back shop for a 161. #90-1173.. Don't know how good it is. I broke the plastic dipstick tube moving it. I'd sell it cheap if you were willing to come get it. Edited November 23, 2012 by squonk

[coldone 35]

It sounds like you arent getting any oil pickup from the sump (transaxle). The lift cylinders get their oil directly from the charge pump, the charge pump gets its oil direclty from the sump. There is a strainer on the intake of the motor housing, that could be clogged. It sounds like you need to drop the rearend and pull the pump/motor to have a look.

[pfrederi 17,886]

I'm with Coldone on this. Thicker oil due to the cold and junk in the system could lead to clogged intake screen.

[stevebo-(Moderator) 8,351]

the second picture shows the screen. once you pull the motor off the screen flange is right there

[can whlvr 993]

this was the problem when my sundstrand just quit all of a sudden,no lift either,if you look close you will see the retainer ring broke apart,

[mattd860 162]

this was the problem when my sundstrand just quit all of a sudden,no lift either,if you look close you will see the retainer ring broke apart,

YIKES! I hope this isn't my problem although I have no lift either!!

The funny thing is that if I push the lever all the way forward and then push the tractor, it will start to go. This technique does not work for reverse but I was able to drive the tractor about 1000ft (forwards) before returning to the garage. Another note - I am able to push the tractor even with the tow valve closed. According to the manual I'm not supposed to be able to do this. I'm hoping there is a stuck valve or check valve somewhere that I can easily clean out.

[mattd860 162]

Ok I starting taking stuff apart today and found some oddities but nothing that clearly explains why the unit has failed. First off, the instake screen has totally come apart. The screen was floating around in the reservoir/transaxle area and I had to fish it out. These are the three pieces I found, but I'm not sure if there are any more pieces in there.

Also - the charge pump gear looks to have some minor wear on it. It's hard to see in the pictures but look closely. I'm not sure in the scoring on the gear is enough to prevent the unit from pumping up the oil from the reservoir.

Additionally - the main sippers (or whatever they are called look good. I haven't taken apart the motor yet because for some reason it was not coming apart. I am also having trouble separating the valve body from the motor but I'm sure I'll figure it out.

The problem I may be experiencing could be in the valving, but remember, I also lost the lift cylinder so that would assume that ALL valves (forward, reverse, lift, and check valves) have dirt or corrosion which is odd.......???? Since I also lost lift cylinder control, I guess it's safe to assume there is nothing wrong with the motor or motor sippers either.

Could the lack of intake screen have caused my problem? I wonder if any part of the screen plugged the hole of the intake port.

ALSO - WHY IS THE FILTER AT THE END OF THE LINE??????? THIS IS STUPID IN MY OPINION. The filter only cleans fluid that has already gone through the system so how does it prevent gunk from the reservoir from entering the system???? Seems lame to me.

[coldone 35]

If the charge pump is that badly damaged, I am betting that that your valve plate is toast. The valve plate is the brass/steel plate that was under the cylinder block. If there is severe scoring on the Valveplate then all the pressure built up by the charge pump is just slipping by from high pressure side to low pressure side.

Be careful with the cylinder block piston combo, the pistons are supposed to be matched to the individual bores.

[stevebo-(Moderator) 8,351]

IMO time to find a donor ... You will go crazy trying to fix that one. Be sure to buy one that you KNOW is good. I know it sucks to have to pull apart your recent restore however I have been there and done that...... It happened to me with the Auto 18 with loader a few years ago. Mine was easier to find the problem and repair tho. Good luck-

[pfrederi 17,886]

Your gearoter (the charge pump rotor doesn't look that great lots of nicks on the teeth, what does the flat surfaces look like also how does the cage it runs in look. As cold one said look at the brass valve plate. Is the piston block you are holding from the motor or the pump?

The piston block in the motor is held on by a spring clip device on the shaft. You have to use and arbor press to get it off. (Check the sundstrand manual). Note even with a press i have had a couple of the spring clips/locks lose a tab in th disassembly process.

As to the filter that is pretty much standard in the hydraulic world a screen on the suction line the fine filtration happens on the return/bypass line

Edited November 27, 2012 by pfrederi

[mattd860 162]

Yeah the valve plate is toast. See the pictures below. It is badly scored. The piston block I am showing above is from the pump. I haven't taken the cover off the motor yet.

Needless to say, I will be finding a donor or perhaps upgrading to an eaton 11 transmission. Even if I wanted to rebuild this one, can I even buy the parts I need (like the valve plate and screen)?????.

[pfrederi 17,886]

Its not the edge you need to be concerned with it is the flat brass surface. Look for wear grooves between the holes.

Some parts are available but the are very very expensive.

Incidentally your pump piston block and slippers look very good.

Edited November 27, 2012 by pfrederi

[WheelHorseSteve 56]

I believe most of the Sundstrand parts are NLA - No Longer Available. That said, there are folks that do rebuild these transmissions (at a pretty high cost -- $500 and up)... I wonder where they are getting the parts? Donor transmissions can usually be found in the $50-200 range. I have my old C-160 one sitting around for the same analysis you just did and another working Charger one as my backup.

If you do decide to do the Eaton 11 conversion, please post pictures! I am sure many would benefit from this tutorial... me included.

[mattd860 162]

Yeah the brass surface does have some scores and grooves. The motor block and slippers are also grooved. Take a look below.

.

Next I'm going to dig into the valve body because the tractor was able to be pushed even when the tow valve was closed.

[coldone 35]

The valve plate for the pump is a standard sundtsrand series 15 "thin" plate 0.156 inches in thickness. The motor valve plate is the same except the inner diameter has been bored to fit the larger needle bearing that the motor shaft uses.

Parts are available from LJ fluid power in Michigan. The regular valve is less than $75 and the motor valve plate is around $250, the gerotor is still available too.

If it were mine I would just lapp the valve plates and cylinder blocks mating surfaces. 30 minutes later you would have a functioning hydro again.Swash plate and slippers look good.

[mattd860 162]

What about the intake screen? Where can i get a new one?

[pfrederi 17,886]

If you can't find one you have all the pieces use some JB Weld.

I am still a bit concerned about your charge pump. is the cage the rotor runs in also nicked up> Also teh flat surface of teh rotor are thy in bad shape? The cage and rotor are available as a set but they are very pricey. This is when a parts hydro comes in handy.