I just picked up a 710B for a song. But like most deals i find it needs some work. I have always found help on this forum so I thought I would start a thread on this backhoe and share what i find and fix along the way. So far the electrical is a mess. Broken wires rusted or dissolved connectors bad or missing fuses. She will fire right up and runs great. The loader and backhoe work well as well, But and you had to know there was one. She will not move under her own power. In First or second gear she will surge a bit like its trying to engage but no go. With her up in the air same thing. Forward and reverse. The higher gears do nothing. I see no major leaks so far and oil level is good. i will be changing all the filters and oils this weekend and taking a few photos to up load. Any one have a idea on the transmission issue? That is if it still has this problem after oil and filter changes.
I'd get the technical and service manual first. Take a transmission pump pressure reading with the old fluid still in it. Supposedly those transmissions are pretty durable, but if it's come apart the evidence will be in the screen. If you do drain it, make sure you get the screen(s?) out and inspected, if there's anything bad, there's no use filling it back up until you look a little closer. I'm guessing (not sure on that model) that the powershift transmission oil pump also charges the hydraulic system, so it would seem that the pump itself is not the problem if the hydraulics are working well. Maybe look at the fwd-neutral-reverse linkage/valve? also clutch pedal and gearshift linkages. Does that have a short driveshaft between the trans and rear end? can you take a floor plate off and see if that spins to be sure it's in the trans. Also, do you get the same reaction going from neutral to 1 and 2 as you get going from neutral to fw or reverse with the reverse lever? No movement in any of the 8fw or 4 reverse?
Finally got a chance to dig into the 710B today. Pressures were all within spec. So I started pulling the transmission out. I pulled the pressure regulator off and found shredded metal and black gritty stuff inside. Went to the shift body next and found more of the metal and black stuff. I found nothing majorly wrong in either section. So I guess, one of the clutch packs or brake packs let loose. I will have the transmission completely out of the tractor this weekend. Then the fun of pulling it apart begins. Pulling the tractor into the shop I had no reverse , just a surge. But I did get first gear, only the second time its stayed in a gear. Once inside i tried a few other forward gears and nothing, even first did not work again. I will let you all know what i find. Thurston
Please save yourself the drama and pain and get the service manuals before you tear into that transmission. You will thank everyone later.
I have the manuals both printed and PDF. Waiting on those manuals is part f the reason its taken me so long to tear into this tractor. Man those were hard to find at a affordable price. Thanks
Good work. Be ready to put some thought into it when fixing that trans. In college I tore down and put back together a Quad range and an 8 sp. Power shift. Kind of tedious jobs. Good luck.
Thanks. My neighbor is a CAT tech and has agreed to help me if i get that 800lb tranny to his shop. Got to love helpful neighbors. Picking up a HD transmission jack tomorrow. Just once I would like to do a job without having to buy tools to finish it. grin . Ah who am i kidding? I love buying tools.
I pulled the transmission out this weekend. What a heavy sucker that it. We have not got to far into it yet, We did find shredded metal and black gunk in the shift assembly, leading us to believe one of the clutches or brakes is done for. More info to come as we dig into it.
We took the transmission apart and found dang near every brake disk bare and shinny. Bill says that happens when water gets in there. The pads absorb the water and when they get hot the water vaporizes and explode taking the friction material with it. With the crappy vent sitting right on top of the transmission I can see how easy it would be for water to get in there. I have a plan for a vent up grade. Looking like about $2000 in parts so far. Now waiting on parts to come in the mail .
Last of the part for this project should be in this Fri. (I hate waiting on parts) I welded up a new bottom for the battery box and used spray in bed liner in it. Looks good on the inside now and added bonus the batteries wont fall out. I keep meaning to take photos while i am working on it but get into the zone ( greasy) and cant bring my self to get the camera greasy. grin.
Finally took a few photos. The transmission is back in the frame and bolted to the motor. Woohoo.. Still have a few hoses and linkage to hook up the put the exhaust back on the motor. Last photo is of the next project. That is the top pin on the Backhoe, the lower plate is blown out. Looks to have been kind of fixed t one point. It will be fun cutting the bad one out without damaging the hoses under it.
Ok pulling my hair out now. Got the tranny in the tractor Pressure off the pump is right at 180 as it should be. When tested in the air ( tires off the ground) every element works perfect till you touch the brakes or drag the wheels on the ground. Then the whole tranny hydro system drops to 40 to 50psi. I can make this happen in higher gears just by giving it full throttle. I cant for the life of me come up with a idea where to look for whats causing this blow off. all the clutches and brake systems hold pressure its the whole system that drops. The pressure does not climb before it drops it just goes. Any ideas?
How about the clutch/torsional damper? If it's slipping under load that might explain the pressure drop even though the transmission and pump are perfect. Just an idea? Really hate to even think such a thing, but that's what came to mind.
you know I was just thinking that as well. sigh. If it is the damper the charge pressure up front should drop also. I will hook a gauge up there and check that in the morning. The fact that the tranny pressure drop to the 50 to 70 that the Charge pressure should be at makes me want to blame the regulator. Maybe i want it to be the regulator so i dont have to pull the tranny back out to replace that 1000 dollar damper. Sigh.
My thinking is the clutch holds on at low torque and keeps the pressure up to spec, when more torque is demanded the clutch starts slipping until the pressure drops to the point that the wet clutches start slipping and it maintains that RPM where the slippage is balanced. My guess is that the main pump charge pressure will drop to the same as the transmission lube pressure (there's an orifice that "bypasses" the pressure control valves to feed lube circuit). The pressure control valve is just three relief valves, the first one releases fluid from the transmission pressure to the main pump charge at transmission pressure setpoint (180psi), the next one releases transmission charge pressure to the lube circuit at charge setpoint (110psi), and the other one releases lube circuit fluid to the reservoir at a lower pressure (32-42psi). I can't see how the pressure control valve could malfunction to cause this, but it's easy enough to pull out and inspect. The clutch valve is another place to look, not sure how/why though? I would have thought that it would be obvious inside the "bellhousing" if the clutch/damper had been slipping. My understanding is that it is similar to a clutch but no release mechanism. Also, I would have thought the hydraulics would have caused the same slippage before? How are the hydraulics working now?
Yep charge pressure dropped also . While pressure was low i climbed under the tractor with my Temp gun and watched the bell housing get hotter till smoke started coming out of the inspection hole. So even though the Dampener looked good all springs in place no rust it seems to be slipping. Sitting here ordering a new one and adding it to the parts list of all the parts i have put in this thing, Something clicked in my hurting head. The main seal on the input shaft was bad (torn). I bet that the dampener is saturated in Hydro oil and can not for the life of it hold on to the flywheel. I am 99% positive this is the issue and 100% pissed i did not pull it out and put my hands on it when the tranny was out 2 weeks ago