ebinmaine 67,460 #1 Posted February 6, 2023 On my mid 70s see series Sundstrand transmission with Hydro lift system, is there a particular way that the system needs to be brought back to life? I'm finding capacity around 5 quarts? I'm assuming I cannot put all five quarts in the transmission at once... Will the system need to be burped or bled or anything like that? 2 Share this post Link to post Share on other sites
pfrederi 17,735 #2 Posted February 6, 2023 Never had to burp or bleed a Sunstrand...I do fill the pump on separated systems (D series). You won't get 5 qts in unless you have completely drained cylinders hoses control valve etc. The 4 bolts on the top of the transaxle are not drilled through so they can't help with letting air escape. I just run a wire outside the funnel and take my time. (some use a soda straw). ATF is thin and goes in easily compared to 90w in gear drives. Fill it up to the top then run it cycle the valve/cylinders then top it off to the dipstick mark. (read screwed in not like Kohlers) 2 1 Share this post Link to post Share on other sites
ebinmaine 67,460 #3 Posted February 6, 2023 2 minutes ago, pfrederi said: Never had to burp or bleed a Sunstrand...I do fill the pump on separated systems (D series). You won't get 5 qts in unless you have completely drained cylinders hoses control valve etc. The 4 bolts on the top of the transaxle are not drilled through so they can't help with letting air escape. I just run a wire outside the funnel and take my time. (some use a soda straw). ATF is thin and goes in easily compared to 90w in gear drives. Fill it up to the top then run it cycle the valve/cylinders then top it off to the dipstick mark. (read screwed in not like Kohlers) Okay thank you sir. This one has been emptied right down to nothing. Rebuilt cylinder. Four new hoses. Transmission is rebuilt. Control valve and hydro pump were sitting on the bench or hanging somewhere for a good strong two months so they're about as close to empty as one could get. The dipstick on this particular transmission is just a pop in like a Kohler big block of the same year. It does not screw in. Obviously I'd have no way of knowing if some PO modified it. Is there a way to check it or understand how much is too much without relying on that dipstick level? 1 Share this post Link to post Share on other sites
pfrederi 17,735 #4 Posted February 6, 2023 (edited) If I have overhauled a hydro pump/motor I always coat things with assembly lube. If yours is very dry I might prime the pump to help start circulation and avoid wear. My Sunnies are older so I have the screw in dipstick only the D200 is new enough to have a push in one. Note the handle of the pushin is the vent make sure it is clear and trust the dipstick. If you rs is a newer piston to piston Sunstrand just pull the plug top center and add ATF to prime pump Edited February 6, 2023 by pfrederi 2 1 Share this post Link to post Share on other sites
daveoman1966 3,751 #5 Posted February 7, 2023 You may find this 'fill-er-up' funnel method useful.. NOTE... do NOT overfill these hydros. If they are overfilled, the fluid...either ATF or 10-30 oil will 'foam up' resulting in power loss with likely internal damage. 2 1 Share this post Link to post Share on other sites
ebinmaine 67,460 #6 Posted February 7, 2023 6 minutes ago, daveoman1966 said: You may find this 'fill-er-up' funnel method useful.. NOTE... do NOT overfill these hydros. If they are overfilled, the fluid...either ATF or 10-30 oil will 'foam up' resulting in power loss with likely internal damage. Here's what Trina put together. 2 1 Share this post Link to post Share on other sites
TractorEd 633 #7 Posted February 9, 2023 (edited) On this ‘79 C-161 , I removed the circled bolt and it does go through and act as a vent. Edited February 9, 2023 by TractorEd 2 Share this post Link to post Share on other sites
daveoman1966 3,751 #8 Posted February 9, 2023 BEFORE removing a 'vent bolt', if that is the chosen method, BE CERTAIN to clean away all the dust- dirt- and any other crud laying around the area of that chosen bolt. These Sundstrand units are VERY sensitive to even minute particles of debris and critical damage can occur to soft brass internal parts of BOTH the hyd pump and the hyd motor. NOTE... Before pouring in new fluid, also wipe off the top of the fill tube...and/or the funnel. If a new filter is being installed, wipe off the area around the base of the old filter BEFORE removing it. Finally thourghly wipe off the trans case side BEFORE spinnnig on a new filter. (Lecture over). 2 1 Share this post Link to post Share on other sites
Sailman 1,291 #9 Posted February 14, 2023 Refilling my GT 14 with ATF fluid was a breeze with no burping. Then when adding 10w 30 to my C-120 it was a mess! I did this before seeing the straw method (great idea). Only consolation was "Rusty" needed a good saturation with oil to salvage the patina....had plenty of spilled oil to work with! I would add slightly less than called for, run it some then recheck levels and add if needed. 1 Share this post Link to post Share on other sites
ebinmaine 67,460 #10 Posted February 14, 2023 46 minutes ago, Sailman said: Then when adding 10w 30 to my C-120 it was a mess! I did this before seeing the straw method (great idea). Only consolation was "Rusty" needed a good saturation with oil to salvage the patina.... I had plenty of spilled oil to work with! Always a silver lining !!! 1 Share this post Link to post Share on other sites
