Cold Hydro

[cwm1276 8]

On my 7117 is takes me at least 5 minutes of run time before the lift will function and it usually takes a couple of minutes to get forward and reverse. The tractor is kept in a unheated garage. I always think I will do something when it warms up but always forget as it works fine in warm weather.

[ehertzfeld 1]

My B112 with a 7000 series tranny in it, takes 10 to 15 minutes before I can move. Just to see if it really makes a difference, I got a Napa filter, and no change. I will get a Simplicity filter next. I doubt it will make a difference, as I think it's a sticking valve, but we'll see.

[PhanDad 1,995]

My GTHL with Sunstrand tranny also takes some time to move when first started in the cold (also an unheated, but attached garage). But I would say time is 30 seconds or so; tractor won't initially move until the hydro lever is moved pretty far forward. After a couple minutes, the normal speeds are pretty much there. Hydro lift is also slow at first start. Don't notice the slowness with my Homelite and Vickers hydro. I attribute the difference to ATF in the Vickers and the thicker hydraulic fluid in the Sunstrand.

[Gary 64]

What Hydro fluid are you running in you tractors? I've switched mine to Dextron (ATF), and am not having any problems with needing a warm up time for the Hydro.

[ehertzfeld 1]

I use universal tractor fluid. It had ATF in it when I got it, it did the same thing.

[kevindb85 0]

quote:

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Originally posted by PhanDad
Don't notice the slowness with my Homelite and Vickers hydro. I attribute the difference to ATF in the Vickers and the thicker hydraulic fluid in the Sunstrand.

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My Sunstrands in my Sunstar and both Deutz-Allis 1920's call for Type F ATF. Kept in an unheated building, and have no trouble. I can just start them up and go.

[Tom45 36]

I have a 7117 with hydraulic lift and a 912 with manual lift. I use universal tractor fluid in both. The 7117 will not start unless the drive is declutched with the pedal or the hydro has too much drag for the engine to start against. I was talking to a Sundstrand technicial who said with a lift the charge pump oil must flow through the lines to the lift valve and back to the pump, increasing the back pressure on the charge pump when cold. He said ATF would be thinner and start better, but would also be thinner when hot and have more internal leakage. Tom

[kevindb85 0]

Maybe it's a difference in the Sunstrands. My manual calls for the Type F only.

[Chris727 1,226]

I think there is a fair amount of difference between the sunstar hydros and the sov. type hydros.

[cojo92 1]

i dont have that problem on my 3416 and it is in a unheated garage too...could it be because my dad and i put car transmission fluid in it!?!??:D

[D-17_Dave 11]

There could be several reasons why some have trouble. A few off the top of my head are your sucking air somewhere on the inlet side of the pump, some sort of restriction, or the pump loosing it's prime by returning the oil towards the reservoir when the tractor sets for awhile. After changing the filter first I'd examine the soft lines from the tank to the filter and pump for signs of age and hardening. You could have a pin hole or bad connection. ANY air leaking into the suction side of the system can result in any number of problems.

[RayS 71]

I use Type F in my sundstrand pumps and don`t have any problems and use NAPA - Wix filters.

[cwm1276 8]

Everyone, It warm out and I am thinking of changing the fluid in the sunstrand. Any tips for a novice? I don't have a remote filter so I don't have any lines to worry about. 1. I need a filter, what is the #, does it need to be a simplicity? 2. What fluid do I need? How much? 3. Where do I drain it? 4. Should I do something with the BGB? I have not touched it in 4 years of my ownership. I am just thinking I want to change all fluids this summer so I am good for a few years hopefully on the hydro and BGB. I am due for engine oil change already. I am looking for a couple belts and a pully as well so I might just put in one big parts order.

[MowerMechanic 0]

old seals sometimes take a little heat to expand and seal correctly

[RayS 71]

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The filter you need is simplicity part number 1709322. You can download a operators and parts manual at the simplicity website. http://www.simplicitytechpubs.com/techpubsearch.php

[Al 6]

Hi, I agree with Dave, check for air leaks. Think the ATF may flow more freely, but usually when I see this, usually a new charge pump fixes it. Also there was a filter change on the units with the short filter on the side of the gear housing. When the GTH-Ls came out there was a noticeable noise with the short filters. Something was changed in the hydro. Anyway Simplicity went to a different filter that is about 1/2 way between the early long filter used in the between the frame units and the short side mount filters. I don't remember the specs, but I know it was changed to reduce whining in the trannys. As I remeber there was a Service Bulletin on it. This problem did not show up until the GTH-L tractors and I don't know if anyone knows what changed. I know in some of the other Hydro tractors, (different tractors and transmissions)there were internal changes made to quiet the transmissions. These changes were chamfering passages etc to reduce noise. There is a lot of science in getting the details worked out in hydros, and a simple thing like the change of surface finish on a drilled passage, or chamfering the corner where 2 drilled passages meet at right angles meet etc can really make a difference in sound levels, and sometimes in aeration of the fluid. Al Eden

[cwm1276 8]

Thanks guys, Question on the air leaks, Why would I only notice it in the winter? Now that is 60+ outside I have no problem when starting the tractor. Plus I don't have the remote filter (it is mounted on the side) so the only hoses are to the lift. How much does this thing hold, how much Type F or ATF do I need?

[RayS 71]

I believe it is around 3 quarts. It states above to hold the relief valve open and fill tube until it will hold no more. Have you downloaded the operators from the link above?

[RayS 71]

I have looked at several earlier and later manuals on changing transmission oil. They all state the same. I believe that they are listing it the way they are so that it would be full instead of just saying a specified amount.

[stumpy 0]

I need to learn about hydros...this 16 GTH is the first I've had. The manual calls for CLEAN, NON-DETERGENT SAE 30 WT. for the hydro. That's what the book says, so it must be right, but it sure doesn't sound right to me. Have they changed their recommendations on this or? Any opinions?

[RayS 71]

My Prestige uses 10W30 motor oil in the hydro.

[D-17_Dave 11]

Carl, part of the reason you may see this condition in the winter is simply the oil doesn't flow as easy in the colder temps. Just like the pump gear sections turn to produce pressure they will also create a very slight vacuum to pull the oil into the pump. Either there is a slight air leak, whitch can be air seepage from a weak gasket since you stated you have no remote filter, or your charge pump is getting a little weak like Al described. The seepage can come from a gasket internally or to the exterior side of the pump. Either way the pump is not getting the needed oil supply in needs. If the pump is weak then you should notice an immediate difference in performance after the oil change if you go to a thinner oil. But since you have the temperature helping you out you may not notice this change as much. Right now your really guessing at the problem as it takes a few special gauges to completely diagnose oil flow issues on any hydrostatic pump system. The good thing is your problem has faded for now and it probably won't get any worse in the immediate future unless you have some sort of catastrophic problem happen. Use it till it quits and then you won't have as hard of a time finding the problem.;):O:o)

[cwm1276 8]

Thanks Dave, I noticed this for 2 winters in a row and did nothing to it in the summer in between and figure this year I will try to do some maintaince to it hoping for a better result next winter. Right now I am fact finding on what this project will require as unlike quite a few of you guys this is my only tractor and I can't have it out of service for more than a couple days especiall early summer when the grass needs weekly mowing.

[D-17_Dave 11]

I would encourage you to find a second tractor. Perhaps a parts tractor or the like that has the same tranny in it so if you start having major problems you'll have a ready supply of parts handy. This might help cover all the unknown issue.

[olcowhand 0]

Totally agree with Dave, get a supply of used parts. I have a parts Allis 416, parts MF12H, and a rear hydro & diff formy MF1650. If anything goes wrong, I'll have on hand most anything I could need. I got them all cheap because I didn't have to be in a rush to get them. You might keep an eye on ebay & put in low bids till you win what you need. Patience is the key to buying low on ebay.