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Faunsdale, AL | You will “get by” returning flow from that pump to the rear sump just because it’s a small motor. I’m not going to suggest ways of doing that because you shouldn’t. That is for 0 back pressure case drain connections when a motor has 3 hoses.
You need to return it into the rear (return) filter to charge pump through front (“transmission”) filter that flows to transmission AND front pump/oil cooler circuit. That’s a mouthful but it describes the oil flow from the SCV’s on a 4440 and almost all other JD tractors from the 10 series through the 60 series. There were upgrades through the decades but they were all designed to perform best when oil from the SCV’s stays in the return circuit instead of dumping to sump.
The important part of that circuit is the oil cooler that’s the tail end Charlie for getting oil flow. If you dump a constant flow from a motor back to sump (like it was a low volume case drain) you immediately cut the flow through the oil cooler by that amount. That’s because the “small-ish” transmission/charge pump must pick up that flow back up out of the trans sump and send it back to front of tractor where it’s pumped right back out to the hydraulic motor by the front pump and does not go through oil cooler. Hot oil returns from the hydraulic motor and dumps directly into the transmission and rear housing sump. You’re using that important part of the tractor as the oil cooler. It can be quite costly!
If, instead, you return that flow from the motor into the normal return circuit by plugging the hose into the SCV or into a port that’s added into the side of the SCV housing or even into a ported filter cover, it ADDS to the constant trans/charge pump flow going forward and since there’s excess, it flows through the oil cooler and returns to trans cooled. You’re rejecting the heat into the air through the oil cooler as designed.
If you plug the sprayer hoses both into SCV, you run the risk of moving lever wrong way or hooking up hoses backwards and pressurizing shaft seal area and blowing out seal on motor shaft. There are special ISO 5675 series (pioneer) coupler nipples that have multiple small holes in the end and a check valve inside to prevent reverse flow. Those are a good idea just so you never chance applying back pressure to the motor by hooking up hoses backwards.
AA59411 is the current part number for the special tip. This works in JD SCV couplers that have been converted to ISO but I am not sure if it’ll work with adapters from ISO to JD style couplers or plugged directly into the single ISO 5675 coupler bodies since it doesn’t have a ball or poppet sticking out of the end to open the coupler internal valve .
Making a dedicated motor return coupler plumbed into the side of the SCV housing works great since it keeps the return flow from motor in the tractor return circuit like it’s supposed to be. I have never seen an isolated female coupler that was for a John Deere style hose nipples, only ISO 5675 series. If your tractor is still using the original JD style nipples, having an ISO nipple on the return hose from the sprayer to couple with your added return coupler will make sure you cannot ever hook them up backwards. If your SCV’s have been converted to ISO couplers, then a special high flow non-return tip is a great idea or mark hoses with zip ties etc.
Maybe someone will post pictures of their motor return setup on the side of the SCV. I just plug mine both into the normal couplers and depend on the non-return tip/hose nipple to prevent damage if I get it wrong. It helps that I have a needle valve control to precisely adjust the flow rate, so the hose that has that valve on it always goes in the same side of the SCV coupler.
Note, if you plug both hoses into the SCV couplers, you should put a stop in the slot behind the lever to block out the center/hold and “raise” or rear positions and lift the float stop up. Then you hook the hoses up so that you push the lever to float to stop the pump and pull it back into the normal forward or lower position to run motor. May have to bungee it back to keep it there if it doesn’t want to stay.
This prevents the pump impeller from creating a small pressure spike if the lever is moved into the center/hold position to stop it. When return flow is suddenly stopped, the inertia of the pump and motor spinning will pump oil from supply hose to return and there’s no place for it to go since SCV is in hold position. This creates a minor pressure spike that I’ve never known to cause a problem but it does make higher than normal pressure on return hose and motor shaft seal area. Probably doesn’t do pump and motor any good either to be stopped suddenly instead of windmilling to a stop from the spray solution drag on impeller
Edited by ccjersey 8/19/2026 22:39
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