New member B1700 HSD Hydro problems

[TheOldHokie]

I have not gone back to check P3 yet - haven't had any shop time for the last few days. That is next on my list. As far as the sound of things - when I try the hydro in gear I get no difference in the engine sound and no difference in the sound at the transmission. The rear wheels do lock up in 4WD mode but I have not checked with it in gear and not in 4WD lately. I'll check. Both pto shafts work. I had to order an adapter for my gauge set to connect to the High pressure ports - it should be here in a couple days and I'll get back on this when it shows up. By the way, if anyone needs hydraulic adapters, Surplus Center in Nebraska has a very good selection at very good prices The SAE #6 to SAE #8 I need is less than $3 from them.

I have not gone back to check P3 yet - haven't had any shop time for the last few days. That is next on my list. As far as the sound of things - when I try the hydro in gear I get no difference in the engine sound and no difference in the sound at the transmission. The rear wheels do lock up in 4WD mode but I have not checked with it in gear and not in 4WD lately. I'll check. Both pto shafts work. I had to order an adapter for my gauge set to connect to the High pressure ports - it should be here in a couple days and I'll get back on this when it shows up. By the way, if anyone needs hydraulic adapters, Surplus Center in Nebraska has a very good selection at very good prices The SAE #6 to SAE #8 I need is less than $3 from them.

Burdens is a good source for many things especially hose assemblies but not the least expensive when it comes to fittings. I buy a lot of pumps from them. These guys are probably the lowest going for fittings.

Hose and Fittings.com

Dan

 

[Dancat]

I just moved the gauge back to P3 and it shows 10 psi at Idle and about 20 PSI full throttle. The pressure does drop a little (about 4 psi or so) when I press the forward or reverse pedals. Also, I can roll the tractor in neutral but it does lock up when in hi or low.

 

[Dancat]

I think I may have made some progress. Not really good news, but I think it points me in the right direction. I noticed that there is a top cover on the transmission. It is the plate that holds the foot pedal for the differential lock. I took that off and started the tractor. You can see the output shaft of the hydro through this top opening. I started the tractor and carefully let the clutch out. Oil poured out around the output shaft of the hydrostat. There is a seal on that shaft, according to the parts diagram, so I would not expect to see a lot of oil coming out there. This is just with the charge pressure. When I pushed down on the forward pedal, even more oil came out. I think my next step is to split the tractor and take the hydrostat apart. Guessing that is why my charge pressure is so low. I will post when I get things apart and get a better idea of what I have. Looks like some parts for the hydrostat are no longer available. I may have a parts tractor.

 

[ruger1980]

I think I may have made some progress. Not really good news, but I think it points me in the right direction. I noticed that there is a top cover on the transmission. It is the plate that holds the foot pedal for the differential lock. I took that off and started the tractor. You can see the output shaft of the hydro through this top opening. I started the tractor and carefully let the clutch out. Oil poured out around the output shaft of the hydrostat. There is a seal on that shaft, according to the parts diagram, so I would not expect to see a lot of oil coming out there. This is just with the charge pressure. When I pushed down on the forward pedal, even more oil came out. I think my next step is to split the tractor and take the hydrostat apart. Guessing that is why my charge pressure is so low. I will post when I get things apart and get a better idea of what I have. Looks like some parts for the hydrostat are no longer available. I may have a parts tractor.

Yep I was going to suggest taking that cover off next. There looks to be a hole just above the output shaft at the top of the HST that is the return to sump for the HST and you will see a constant flow from this into the transmission case. This is the combined flow from the power steering and charge pump.
But it does look like the next avenue is to remove and inspect the HST unit. You will probably find an issue with one of the pistons or valve plates. While it is apart I bet you find your problem with the front drive shaft too.