Need Help On Hydro Trunion Pump Change. 1782D Swap to a 1541

[otep858]

Hello everyone. I'm fairly new here but I think that the pump is going bad on my 1782D. I've read thru everything that I could find on this very helpful site. My problem is that my tractor will go fine on the flat but if you put a load on it. You have to push the lever all the way up to barley climb a hill. And the reverse is so weak that you can't back up unless its perfectly flat. And it will free wheel downhill pretty bad. I'm constantly having to adjust the speed lever to get a constant mowing speed. The lever isn't moving freely and its tightened to where it should be. I've replaced the the linkage to the trunion, the cam, the trunion springs/keepers, ect. The bracket that the cam fits into that holds the springs, another big problem fixes that I've found on this site. Is to use and change the hytran and filter with only cub cadet fluid and filter. I've changed both twice. To no change. Only thing left that I would know is the trunion pump. Along with the charge pump. Is that something that you would agree with. Also I've found a pump from a guy that came off a 1541. Will that work on my 1782 super? Any help would be very much apreciated. I'm pulling my hair out here. Lol. Also I have done the presure test with a gage and its with in range at full throtle. With no load. But it drops off bigtime when its at half throtle. Thanks in advance for any info. And thanks for the very helpful blog you have here. Also forgot to mention but I've also swaped around the relief valves and cleaned then they both work good. Makes no change when I cleaned them and made sure they were both working properly and swaped them around. Andy other sugestions?

[Farmallgray]

What were the pressure readings? Does it speed (ground speed) up if you use the hydraulic lift when you are moving? What is the pressure when you work the lift?

[otep858]

Todd ill have to get back with you on that one. Can't remember for sure. As far as the readings however it does NOT speed up when you operate the lift.

[Marlin]

Howdy... I'm confused here with the trunion pump thing? However... you've provided us with not enough information. I.E. How many hours and what kind of history is behind the whole tractor. Did this happen all of a sudden or has this been building up over time? You haven't taken the charge pump apart have you?

http://www.sauer-danfoss.com/stellent/g ... n-9646.pdf Here is the manaul for you to review.

Hope some of what Farmallgray has asked also helps.

[otep858]

Marlin, the history and hours are I've owned it for almost a year. The meter shows that it has about 700 on the machine. The guy I bought it from told me that the pump was going out of it when I bought it. And that a new pump could be bought at the cub dealer for 500. I had done some checking around on this forum and was hoping that the guy just didn't know what he was talking about. Ie. Most obvious thing was to change the fluid and filter with cub trunion fluid and filter. I've done that to no change. As far as the presure I can't test it again right now. Because I'm out of town for a few months. I just know that as long as it was runing at full throttle that the pressure was within the specs. And would go way up when you would operate the lift... if it was at half throttle the preasure would be waaaayyy less. As far as what it does. It just seems to have no torque. Not the motor. But the ability to pull a hill. And going down a hill I have to pull the handle way back to keep it from speeding away. Last thing I have tryed is the cam was worn somewhat so I changed that. And the linkage ends from the handle to the cam and the springs and keepers at the trunion. Pulling my hair out on it. I will post the presures that I get on it when I get back home. Also since I now know that a pump off the 982 won't work I've found a whole pump off a early style 1541 that a guy will sell me that he has. Everything that I've found so far it looks like it will work. Is that correct

[otep858]

Also no I havnt takin the pump or charge pump apart at all. Have no history of the tractor prior to buying it almost a year ago. And the guy did tell me that it had pump problems.

[Marlin]

I'm not too well versed on what pump the 1541 has. By that whether it is a 15U or a BDU10L. I bet that Rich could help out with that. $500.00 sounds cheap for a complete and new BDU15L series pump and yes... I know for a fact that you can still order one new. Your best bet is from a Sauer Danfoss Distributor in your area though. It will be much cheaper than through a Cub Cadet dealer. You will need all the information from the I.D. tag if you chose to go that route. ... NOW... Sauer Danfoss is discontinuing the 15 Series in 2014 however parts will still be available. By that you won't be able to order a new complete unit. They will still support parts and rebuild your old unit though.

I did ask a gentleman today about your pump and he agrees that it is more than likely worn out. However 700 hours isn't much for that pump and they with normal maintenance should easily last 4-5000 or more hours. Things that will make a pump go south in a hurry is ... use the wrong oil in it or run it dry... dirty oil, etc. At this time I am thinking someone proably put the wrong oil in the system and therefore ruined the pump. For your benefit, I would go with the pump that Rich Patton has for you. Be sure to flush your system out with the correct oil a couple of times before installation of the new pump and you should be good to go.

Keep us posted. You will love that tractor once it is up and running.

[Tom Scott]

If you are going to replace the hydro, it must be from an SGT, not a regular GT. The Super hydro is a different version of the 15 series from what they put in the regular GT. The 1541 is a regular GT, and may even have the newer style BDU-20 hydro.

If you are a decent mechanic, and can read and follow directions, rebuild what you have. All the parts are available. If your lift is working well, it sounds like your charge pump is fine. The charge pump is one of the most costly parts, so you have probably dodged that bullet. Most likely you will need to rebuild/replace the main hydro pump and/or hydro motor blocks.

To do this, you must follow the Cub/Sauer-Danfoss directions and work very clean. The secret is a nice big clean table, lots of light to see, paper towels (not rags), and work surgically clean. Do some reading; they are remarkably simple devices and really aren't hard to work on. You just have to be very clean and follow the directions exactly.

[vince_o]

Ill have to say they intmadate me, but Ive done a few on 2000 seres. Frank dose all of the trannys for the most part. But belive me, if I can do it, you can too. Im no mechanic, just love to fix things.

[Marlin]

From what I have noticed looking at the Cub Cadet parts site the main differences between the two pumps is the two shafts. Now... once again you can rebuild the pump only in doing so are you VERY familiar with what to look for as far as physical damage to any of the parts? With this I'll tell a true story... A good friend of mine bought a LOW hour JD 318. He was told the hydro was a little sluggish. Now he is a retired Sauer Danfoss engineer and very familiar with the products/pumps. When he went to do a fluid/filter change it was then that he discovered that someone had put something the equivalent of 90 weight transmission oil in the system. Yes... he did several filter/fluid flushes. As he told me... Once you use that heavy of an oil things tend to really wear out in a hurry. I asked him if the pump could be rebuilt and he said that you could maybe salvage the shafts and swashplate and housings. The rest of the internals should be replaced. By the time you do that you can buy a whole new pump a lot cheaper. Once again... 700 hours if actual isn't many hours at all on such a pump... IF it has been properly maintained.

Just my thoughts...

And if I recall the newer replacment style 20 Series wasn't around when those tractors were made. Plus they are pricier than the 15U and that is one of the reason I believe Cub Cadet chose to go to the BDU21L and 10L Series was the cost factor.

[Marlin]

I hope that I haven't upset or scared anyone off with my last post. However if one thinks about things then you will also realize that 700 hours on a 15U if otherwise properly maintained isn't many hours at all. Right now I am in favor of checking all pressures using the Sauer Danffos and Cub Cadet Service manuals and in accordance with how to check the pressures. It may be a simple charge pump needs rebuilding and some springs/shims need replacing. If I recall the pressuers should always be checked once the system is at normal operating temperature and never first start cold temperature. Please keep us updated.

[MikeMasheris]

Don't forget about the output shaft being smaller output gear and larger reduction gear than standard Cub Cadet.

[otep858]

So as far as making 1 good pump from 2 (my 1781, and the 1541) the only things that are differnt are the output shaft to the transmision (differnce between the regular garden and the super garden) because they are both 15U pumps. As I said before it looks like in comparing part numbers the only ones that are differnt between the 2 are the output shafts. So I could take the blocks out of the good pump and using them I'm mine. Understandably. Ill double check the presures first. But looks like rebuilding and even just replacing the motor block is way expensive. And the pump that I can get from the 1541 is a good deal I'm my opinion as its 500 for the pump plus a 551 blower. And its relaivly close to where I live.. any thoughts on combining 2 pumps to make 1 good?. Thanks for all the help here guys, Paul

[Marlin]

I'd go for the making one good one out of the two. Thank You for the update and keep us posted.