my dozer has a peculiar problem. after 2-3 hours of pushing, it all of a sudden loses all power. almost like a flick of a switch. it will push hardly anything. and the engine starts heating up quickly. i can put it in neutral and it still struggles to get it's rpm up. if i let it cool down for a couple hours it'll be fine again for 2-3 hours of work. any thoughts?
check to see if loosing oil pressure. There is an automatic thing that puts engine to idle with low oil pressure. Did it on my D7E when it had a weak oil pump.
I don't know much about this stuff but maybe water/fuel separator is a little loose? Well, that was the problem on our skid loader with the same symptoms.
Check the oil level in the trans as it looses power? May be flooding the converter acting as a hydraulic retarder.
engine oil pressure and fuel pressure are right up. define flooding the converter? what causes this?
Excess clearance in the wheels (stator and turbine), poor scavence pump, too high pressure setting in inlet relief valve or a restriction in the system. Does the converter get hot as it looses power ?
i'm not sure if it gets hot as it has no gauge. i put my hand on the bellhousing as it was acting up. i could touch it but couldnt hold my hand on it. i would expect it to be that warm?
no power I have a 1973 d7f it was the first dozer we ever owned bought it from Cat dealer it used to belong to Freesen and for an F model some guys said it was one hell of a horse. Freesen probably had it turn up the engine use to never pull down they had completely rebuilt the whole tractor my dad had an old friend that was one of their mechanics who gave us all the history on it bofore we bought it its still in good shape but when you start it up it seems down on power and slow after you run it for a while it gets better but its nothing like it use to be i have changed all the filters any ideas?
The converter housing on a D8 should have about 4 gallons in it, if you pull the plug and get 7 or 8 it's flooding
where is the scavange pump on an old 8h ser. number 46a7080
should be down on the bottom of the torque converter.
alright fellas i think i have a working theory here... last time i parked the cat it was acting up. i went this morning and checked the trans oil before i started it and it was completely empty (off the dipstick) then i started the engine, waited a minute and checked the trans oil again--- it was coming up the dipstick about an inch i'm guessing the torque was flooded? now i replaced the trans pump a bit ago because it was wore out (wouldnt shift properly when the oil got warm due to low pressure) and i never had this power problem before that. now what i'm thinking is once the oil gets warm the scavange pump is probably too wore out to keep up to the new trans pump, therefore flooding the torque eventually? does this sound like a plausible theory or am i missing something?
Maybe, Maybe not. Transmission oil leve is meant to be checked when engine is running. Check your oil level with the engine running to make sure it is in the operating range. If you are working slopes you can go up to 10.0% overfill. There should be something in the manual about scavanger pump pressure you can check. Or, do you have the correct oil in the transmission too? Cat says to use straight 30 weight.
yeah i'm using torque series 4 30 weight
There should be an engine stopped side and an engine idle side on the dipstick, make sure you're checking the correct side. (not sure how late back in the models they started doing that).
There will also be a screen in the pick up for the scavenge pump that could be blocked. Pull the scavenge pump off and strip and the end plates and gear faces will soon reveal their un-willingness to play with you!!
i cant believe i found this thread... it was the scavange pump. i took it off and pulled it apart--- it was toast. put a new one on and it works 100% or better. i love my old d8H!
How GOOD is that! Congrats!
Thanks for letting us know the solution! So did it take you a year to fix it or a year to remember to post the solution? LOL I have a hard time remembering things from the house to the shop sometimes myself.
i put the new pump on in winter-- but i farm so i didn't get a chance to use the machine again till october. but it hasn't missed a beat yet. turns out what happened was i replaced the trans pump first, because it was losing pressure when it got warm. it fixed my shifting problem, but then when it got warm it started over supplying the torque because the scavange pump couldn't take the extra oil away quick enough.
Did you find any junk in the system or on the magnetic screen.? Just wondering
nothing out of the ordinary
Glad you got it fixed. Those old cat's are pretty tough.