after about an hour of heavy pushing it gets hard to pull into gear at a very low idle. a quick blip of the throttle and it pops right in. works totally fine otherwise. seems like a pressure problem? any thoughts?
stick shift or powershift? intermittent fault or regular?
every gear or one in particular?
it's a powershift. it's a consistant problem when the machine is worked for a while, it becomes hard to pull into gear when you're switching from first to reverse, or vice versa. if i keep the engine rpm up a bit it goes in fine.
Pump snag, That sounds like a powershift tractor to me, it sounds like your oil pump is knackered, it comes off real easy, only 2 bolts hold it to the case and 4 bolts hold a bit of plumbing to it, its best to remove the screen unit as well to have a good look inside and to do a clean up number on it, the pump will need priming before its bolted in place, and the cost of a non CAT pump (in the U.K.) is about £225 = $450 lets hope its cheaper in the U.S. tctractors P.S. always check inside the pump before you spend any Cash, you are looking for gear wear and also bush/bearing wear, good luck.
you talking about the pump on the back right side of the engine?
Pump The transmission pump on your tractor is found on the front right side of the Flywheel case, you cannot miss it, you could do a pressure test on it via a small pug on the pump or the vent/test point on the high pressure filter lid if you wanted to waste a bit of time. tctractors
what should the pressure be? around 350psi? and to make sure we're on the same page, the pressure line from the pump goes to the filter housing, then to the steering valve relief?
Oil pressure. If you want to make a full inspection of the oil pressure settings you will have to obviously have to run the tractor untill hot, then test at low/high idle, the transmission has a safety valve (low pressure) that inhibits gear selection if the oil pressure drops to low to save you damaging the transmission through plate slippage caused by poor clamping pressure, sort the pump (or at least have a look) and I will be only to happy to take you through a full pressure inspection, but knocking the hell out of it like it is by testing all the points is only doing harm , once the pressure gets below 255psi damage starts, tctractors
things i have done to it so far with: tested pressure at pump: 100psi cold, 50 hot. pressure went up to 200 when applying steering clutches or making a brake application. either hot or cold. i replaced the pump, and cleaned suction screen. gained about 50 pounds on either a steering clutch or brake. nominal pressure remained at 50psi i traced the pressure line back throught the filter housing, and to the steering clutch relief valve. i took the relief valve apart and found that somebody prior to me had been in there, and installed the whole piston\spring assembly backwards. i took the entire relief valve housing off and cleaned in up, put everything together properly. i'm still at around 50-100psi nominal pressure, but now have 300 psi when making a steering clutch\brake application. pressures were all tested at the pump. transmission still acts the same. this is as far as i've got.
sledgehammer, Where are you taking your pressure measurement when getting 50-100 psi? At the filter housing port? I would expect that pressure to be more like 350 if it's anything like my D6c. You say the pressure goes up to 200 when applying the steering clutches...is that the pressure taken at the oil line going to the steering clutches? 200 psi doesn't sound like enough to disengage the clutches..are they working ok? (I'm curious what your problem is, because I've been having a steering clutch release problem myself on a D6c...don't want to hi-jack your thread so I'll start another one for it)
You may have internal leaks in the transmission.
i'm taking the pressure reading right on the pump on the back right side of the engine. steering clutches seem to work just fine.. i have them running at 300psi now anyway.
Sounds to me like your steering control valve has an internal pressure leak. This tractor should have a priority valve that ensures the brakes and steering clutches always have full pressure, even during transmission shift modulation. What is your serial number? Chances are your transmission shifter would go into gear while the steering levers are pulled, right?
I had a similar problem on a D7E . The spool valve on the top of the tranny that the gear selection linkage operates was warn a little causing internal leakage and pressure on both sides of the spool . I sent it away and had it metal sprayed and turned back down to the correct size , it worked perfectly after that .
i tried that actually... still really doesn't make a difference. an old old cat operator dude told me i shouldnt be shifting it at that low of rpm anyway.. he said minimum of half throttle to keep the pressure up. seems to work really good. any thoughts? and an older hutterite gentleman says he has seen this problem lots, and i should change all my tranny hoses and o-rings, especially the suction ones because they're getting rotten. i already had a couple pressure lines develop pin hole leaks...
Shifting at low idle shouldn't be a problem. Depending on the age of your tractor, you may not be dealing with the right pump. On Older 46a's the pump on the engine was for steering only, the transmission pump was driven off the rear of the torque converter, where the scavenge & circulating pump is on later machines. Make sure what your'e dealing with. I've got manuals for both. Whats your serial? You may just have a plugged screen under the seat area.
thats what i thought! all the heavy equipment techs i spoke to around here thought i was retarded when i told them there is another pump that was on the rear of the converter. it is an older 46a7080...
Well according to my books, your transmission pump is a single section gear pump mounted to the left rear (upper) part of the torque converter housing. If you remove the floor plates it should be fairly easy to access. I dont see a suction screen. The filter should be on the left frame rail close by. If it was me I would check the pump suction line out, then I might pull the top cover off the transmission start the engine and put it in gear. I think you may find a geyser of oil coming from a leaking O-ring. These transmissions have little steel tubes connecting the control valves to the clutches and to the outer hose connections, and each tube has 2 yellow o-rings on each end. it is very common for these rings to blow out and cause the exact symptom you describe. Be extra careful running the machine with the covers off, and expect a wet oily mess. Your problem could easily be a $5 o-ring, but it could progress into a transmission rebuild if not soon addressed. P.S. please post some pics of your machine, we'd love to see it!
bolt thrower okay right on i'll give it a try when i get a chance. i do know that the big suction hose from the bottom of the trans to the pump is in poor condition. i have a couple crappy cell pics of it at the last job i did. pushed up 80 acres of stumps and sticks
ahhh dang it i'm having trouble loading pics. i'll try again later
I have a few D8K's, and i have had many many many many problems with tranny pressures and so on. It just happened saturday night i was running my older girl and she totally stopped shifting.... played with the lever for a few seconds and away she went again for the rest of the day. Then this morning i flashed her up again and went back to work for about 10 mins.... it started to get sluggish shifting and was hard to shift from reverse to forward at low idle..... having had replaced all the suction hoses and o-rings this spring i proceeded to take the top of the transmission apart and check out the pressure control valve, load piston.... etc. well what i found was a a small chunk of black rubber from an old hose stuck in the safety valve oil passage. put her back together and worked like a charm all day today.
well i got it fixed--- once i was pointed in the right direction of where the actual tranny pump was on an older 46a d8h got the pump off and all apart, and the housing facings were toast. probably at least .025" of wear on the housing facings, and the gear bushings were wore out. i put a new pump on, and ran it all day today. worked perfect! didn't hesitate for me once. thanks everyone for your help.