riki1975 3 #1 Posted April 18, 2020 Hello, I have a new to me 18 Automatic that I believe is a 1973. I decided to do some maintenance on it and change the transmission fluid. The fluid that drained out was pink ATF. I let the fluid drain for a couple of hours then put 4 quarts Dexron 3 back in. The dipstick was measuring over full so I took about a quart out. The dipstick now reads just over full but when I start the tractor I have no Hydraulics nor forward or reverse. Could this be a problem of not enough fluid or does anyone have suggestions for troubleshooting. I believe Sundstrand 90 takes 5 quarts but I only have 3 in and it is measuring over full. I also put a new Wix 51410 hydraulic filter on. Any advice? Thank You Rickie Share this post Link to post Share on other sites
bc.gold 3,403 #2 Posted April 18, 2020 Did you prime the new filter. Share this post Link to post Share on other sites
pfrederi 17,867 #3 Posted April 18, 2020 (edited) Tow valve closed??? Left side I have never had to prime the filter on a Sunstrand.... Edited April 18, 2020 by pfrederi Share this post Link to post Share on other sites
riki1975 3 #4 Posted April 18, 2020 No, I did not prime the filter, would that be something I should do? The tow valve is closed. Thank you for the suggestions. Share this post Link to post Share on other sites
pfrederi 17,867 #5 Posted April 18, 2020 Unless you have completely disassembled the system you will never get 5 qts in. 4 is reasonable but three should be enough to get it to work. Did it work before you changed fluid? Engine running try the mid mount lift while you wartch the coupler between the Engine and the pump. Could have stripped splines allowing slippage 1 Share this post Link to post Share on other sites
riki1975 3 #6 Posted April 18, 2020 Yes it worked before I changed the fluid. When you say coupler do you mean the area in the attached picture? Share this post Link to post Share on other sites
pfrederi 17,867 #7 Posted April 18, 2020 (edited) Yes watch and see if the splines slow down. If it worked well before this is probably not the issue but worth checking. Also put some more ATF in the rear end. even if it is overfull it will settle down when it starts working. The filter on a Sunstrand is on the return to the reservoir so there is no need to prime it. I have never had a problem with my D 200 priming it self but I suppose if your charge pump is a bit weak that may be a problem. D series (of which your Auto 18 is the earliest model) are not always mechanic friendly. To help prime the system remove the battery and you will see the top of the pump. Remove the circled plug and try to pour in ATF Edited April 18, 2020 by pfrederi Share this post Link to post Share on other sites
riki1975 3 #8 Posted April 20, 2020 ok, yesterday I primed the pump but it appeared to be full, I also checked to make sure the hydraulic filter had ATF in it and added additional ATF. I still have the same issues of no lift, forward or reverse. I watched the splines and they did not appear to be slowing down at all. Any other suggestions on what I could try? I appreciate the suggestions. Share this post Link to post Share on other sites
pfrederi 17,867 #9 Posted April 20, 2020 The charge pump is what operates the lift. It also feeds the high pressure system that makes her move. it is a georotor pump running at the end of the Input shaft (splined shaft you looked at) if the input shaft is turning the charge pump shroud be pumping. However if the charge pump relief valve spring broke or the valve got stuck or something stuck in it keeping it open then the charge pump cannot make sufficient pressure to make things work. diagnostically the next test should be a charge pump pressure test as outlined in the manual. You use the port Indicated to check/prime the pump. Where are you located? Share this post Link to post Share on other sites
riki1975 3 #10 Posted April 20, 2020 I am located in Runnells Iowa, I will check the manual Share this post Link to post Share on other sites
pfrederi 17,867 #11 Posted April 20, 2020 22 minutes ago, riki1975 said: I am located in Runnells Iowa, I will check the manual If you do not have a pressure tester. I can loan you the stuff you need for postage. Share this post Link to post Share on other sites
riki1975 3 #12 Posted April 20, 2020 Sure, That would be great. Please let me know what you need to proceed. Share this post Link to post Share on other sites
pfrederi 17,867 #13 Posted April 20, 2020 PM me your address...I think they fit in a small flat rate box Share this post Link to post Share on other sites
riki1975 3 #14 Posted May 4, 2020 Ok, I pressure tested the tractor today. I hooked up the pressure tester and moved it into forward gear expecting the tractor not to move and it took off. Suddenly forward and reverse along with the mid and rear lift all worked. I then took the pressure tester off and put the tractor back together and she had no Hydraulics. The pressure test was only measuring 60 without the lift and jumped up to the 600 range when the implement lifts were fully up or down. I cranked the engine up and the hydraulics worked well enough to get her back in the garage but not sure what could be causing the intermittent loss of pressure. Has anyone experienced this issue before? Share this post Link to post Share on other sites
