Hey guys, I'm new to the heavy equipment world. I bought this machine a few months ago. It was low on transmission fluid when I got it. So I started it up and poured a couple of gallons in until I got it within range. Used it for an hour here and there ofr a while, then decided to check after running one time and the oil level was very high with bubbles in the oil. I have replaced all suction side seals, replaced the seals on the transmission pump, drained and replaced with Cat oil, checked suction screen(clean). I used it hard for about an hour yesterday and lost all forward gears, reverse worked fine. I let it sit about an hour, the all worked again, not sure if it's because of the foaming but I suspect it is. Don't have a gauge yet to check pressures, but beyond that I don't know what else to do.
Please post a Serial Number to make finding info easier. What oil are you using in the transmission.? How are you checking the oil level.? When you drained the oil and refilled did you remove and clean/inspect the magnetic screen in the pump suction line.? Do you have an Operation & Maintenance Manual for it.
SN: 29y01769 I am using cat oil, 30W. Checking level with engine running, neutral I did check the magnet/screen. Screen was clean and magnets had very thin layer of paste. I do have the manuals. Thanks
Did you clean the vent/breather on the transmission and replace the trans. filter when you changed the oil? 29Y is a 3F/3R trans. and uses a filter. The 3F/1R trans. just uses a screen. Thinking a partially blocked filter or plugged breather could cause foaming of the oil.
It is a 3F/3R. Yes I did change the filter and the breather. Two questions come to my mind: Could a worn pump cause air to enter through the bushings on the side of the pump that connected to the gearbox? And I need to make absolutely sure my suction screen is installed correctly. The manual just says to install it. The magnet assembly fits right inside the screen, and the screen/magnet assembly just sits on top of the plate that is on the bottom of the transmission. The screen isn't supposed to "snap" onto place anywhere is it?
We went through this with a different machine some time back and the answer was no.
Could the filter not be seated properly or a seal got rolled or something, maybe a torque converter issue? I have a 3F/1R trans. and have never had any issues with it. Hope I don't jinx myself.
I feel good about the seals on the suction side, because it is doing the same thing as before I replaced them. So mine has the screen on the suction side, and the filter just after the pump on the pressure side. Being the filter is on the pressure side, is there any way that could introduce air into the system? And I don't know much a torque converters, could it possibly be agitating the oil somehow?
No. If there was something amiss in the filter area oil would be leaking out. The pressure in the line from pump to filter is somewhere around 350psi.
I would change the transmission pump had those suck air even though you resealed it. Do you check the oil with the engine running in neutral High oil level can aerate the oil
Yes, a while back I started it, left it in neutral at a very slow idle, checked it 30 minutes later and could tell it already had tiny bubbles in the fluid. If I keep running it, there will be bigger bubbles on top, I suppose from smaller ones combining. So Dave you have seen a pump fix something similar to this? What kind of machine was it? Thanks for the help!
D6C
And to answer you question of checking the oil, yes I start it it leave it in neutral. The level is high before starting the drops down in proper range on the dip stick when started (which I understand is correct)
So long as there is oil visible somewhere on the stick it's safe to start. The time to accurately check the level is with machine on level ground, engine idling, trans in neutral, and all systems at normal operating temperature. Where exactly is the oil level on the stick when you measure it that way.? There was also a similar issue a while back of bubbles in the powertrain oil that was eventually fixed by a replacement transmission pump on a 938G loader IIRC.
When I first start it the oil is in the proper range, if I let it run a while and warm up it starts to rise with the air bubbles. I suppose it is possible there could be too much oil and it aerating. I certainly may try to drain some out and try it like that before I replace a pump. Do you think heating the oil and components would cause it to expand that much?
Not really but that is supposed to be the status of the machine when the oil level is checked. There will be a significant difference in the oil level between engine stopped and engine idling. Try draining out some oil so that when you first start the engine and the oil level drops that it is right on the "ADD" mark on the stick. Strictly speaking anywhere between the ADD & FULL marks is OK. See where that gets you.
It will be a couple of days, but that is what I try next. I appreciate the help
Yesterday I drained a gallon out, so it barely registers on the stick. Level eventually rose to an inch above full mark with bubbles. I ran it hard for about an hour and noticed it hesitated for a second when going into forward gears for a couple of times, then lost all forward gears. Started backing it to the parking spot about 200 yards away, and by the time I got there the forward drive worked again. Is it worth a shot to spend 800 on a pump and try it?
You can get a aftermarket one for half of that
Dave I hope so. The part number is 9P7239, and just me searching online for aftermarket or not I can't fine one under 700. Can you recommend parts suppliers you have dealt with? Thanks for your help
689 is the best I could find too
That's not real bad in terms of repair costs.