kenmill1958 0 Posted February 5, 2010 I have heard different types fluid bieng used in the hydros in these tractors. From OEM to Dexron and hydro fluid at tractor supply. I do not mind using after market types as long as it doesn,t cause problems. Any help appreciated. Thanks Ken Share this post Link to post Share on other sites
UCD 14 Posted February 5, 2010 I used Dexron ATF in my 7790 for 25 years with no Problems http://www.simpletractors.com/club2/topic.asp?TOPIC_ID=22258 Share this post Link to post Share on other sites
kenmill1958 0 Posted February 5, 2010 It has the regular hydro fluid in it now. I guess I could drain it change the filter and ad the ATF instead. How did you know to use the ATF fluid?? Share this post Link to post Share on other sites
UCD 14 Posted February 5, 2010 Dealer told me to use it and the chart specfies it. Share this post Link to post Share on other sites
ac.d17iv 7 Posted February 5, 2010 I second Dextron. I'm using Dextron ATF from Napa, along with a Napa (Wix) filter. My manual for my 712 specifics Allis fluid or Dextron. Share this post Link to post Share on other sites
PhanDad 3,251 Posted February 5, 2010 Maynard, I'm a bit confused. Isn't a 7790 tractor a "7100" series with a Sundstrand hydro? The chart you referenced calls for "Simplicity Multi-Purpose Hyd Oil". I thought only the older Vickers hydros specified Dextron Automatic Transmission Fluid (the red stuff). Share this post Link to post Share on other sites
kenmill1958 0 Posted February 5, 2010 Thats what I am understanding from the chart also. 7100 series doesn't give an option of Dexron Share this post Link to post Share on other sites
RayS 79 Posted February 6, 2010 The operator manuals state more varity that can be used than the chart does. This is a operators manual from a 7100 series. States the type of oil that can be used. [img]/club2/attach/RayS/Untitled.jpg[/img] The Allis operator manuals do state that you can use dexron though. This from a Allis 700 series operator manual. It states you can use Dexron in the sundstrand. I use Dexron in my now because both my vehicles call for it as well. Since the Sudstrand use the same replacement part numbers and the Simplicity and Allis operator manuals state you can use it. I feel that it is safe to use the dexron. Share this post Link to post Share on other sites
kenmill1958 0 Posted February 6, 2010 Thanks Ray sounds logical to me. I was hoping I could use Dexron also. I have at least 5 gal. Some of my other vehicles use it as well. Easier to stock one fluid also. Thanks Again. Share this post Link to post Share on other sites
RayS 79 Posted February 6, 2010 I suppose that I should have stated it is the Allis operators manuals that states you can use the Dexron oil. The Sundstrand is the same in the Simplicity and Allis tractors so I don`t see the big deal. Probably more like a manufacture recomendation or brand loyalty type of thing. Share this post Link to post Share on other sites
Burntime 1 Posted February 6, 2010 I can tell you I switched out to hydrotrans simplicity stuff and it works well. My problem is that I did not run it to mix in the water and in extreme cold it is sluggish cause of water in it. I am changing it out this spring with mercron 4 or 5. Make sure you run it good and hot before you dump it. The simplicity stuff is also wayyyyy overpriced... Share this post Link to post Share on other sites
UCD 14 Posted February 6, 2010 Yes the 7790 is a 7100 series tractor and it has a Sundstrand 15 series hydrostatic in it. The chart showes dexron for the sunstrand 15 series in the Sunstar and Power max series and it states dextron. The SundStrand 15 series manual. Dexron meets these specs. Fluids Ratings and data for Sauer-Sundstrand products are based on operating with premium hydraulic fluids containing oxidation, rust, and foam inhibitors. These premium fluids include API CD engine oils per SAE J183, Type F automatic transmission fluids, power shift transmission fluids meeting Allison C-3 or Caterpillar TO-2 requirements and certain specialty agriculture tractor fluids. For further information, consult Sauer-Sundstrand. At continuous operating conditions, fluid viscosity should be above 55 SUS (9 mm2/sec). Minimum fluid viscosity should be above 45 SUS (6.4 mm2/sec) at intermittent operating conditions. Filtration A 20 micron (nominal rating) filter should be placed in the inlet line to the charge pump. The maximum continuous inlet vacuum should not exceed 10 in. Hg (0.7 bar abs.); the filter should be replaced when the inlet vacuum exceeds 10 in. Hg (0.7 bar abs.). During cold starts, the inlet vacuum may exceed this level. Inlet vacuum at normal operating conditions should not exceed 5 in. Hg (0.8 bar abs.). Share this post Link to post Share on other sites
RayS 79 Posted February 6, 2010 From the Sundstrand repair manual. Share this post Link to post Share on other sites