A friend of mine who was a professional dozer operator for 22 years and now is raising cattle like me, stopped by my farm. We were discussing my Cat 2005 D3G. I was telling him about how I prepare some of my steep land for seeding new pasture. I stated that after I put down the seed mix, I walk the seed in by tracking up and down the hill. He said be sure to never go up and down a hill backwards (with the back of the dozer pointed up the hill). He stated that the oil pump is at the back of the engine and when the oil runs forward, the pump cannot pick up oil to push through the engine to cool and lub the internal engine parts. Is this true? I would think the design of a Cat Dozer made in 2005 would have resolved such a problem. I have backed up the hill if that is the best way to go. In some circumstances where the fence line is at the top of the slope I do it out of need to get closer to the fence. He is older then me (68, I am 62) so maybe he is talking about the older machines when he was an operator.
Pipeliner's today working on the steep stuff still run blade uphill... I know you could put a scavange pump on some of the loder cats like a 8k specifically designed for working steep ground as well. Exactly how steep are we talking?
If its really steep terrain, I've heard of people adding extra oil so that oil starvation doesn't happen. How much extra oil for a D3? That I have no clue about.
When I was a kid, I remember my dad telling operators on the sites (building interstates) to never back up a hill or turn and come down the slope...never knew why (I was only 3-7 yrs old)...now I do. Hovis
Don't know about the D3, but my D6c (3306 engine) has the oil pump and main pickup in the front and a secondary pickup in the rear of the oil pan to prevent starvation on slopes. The pump actually has two sets of gears, one for the front pickup and one for the rear. I have heard of problems with transmissions starving for oil on steep slopes and having the trans release and go into freewheel...not what you want on a slope. Cat does say you can overfill the trans by 10% to prevent it. (for D6c type transmissions)
Your D-3G will go either direction as steep as it will climb, and then some without any oil issues. Some much older machines had limits, but all dozers I have seen are rated to at least a 45 degree angle, which is a 1:1 slope, or 100% grade. In most conditions, it will loose traction waaay before it has any oil problems. Same for the hydrostatic trans. You still want to go up and down hills with the front pointing up for better track life, as well as better traction due to the weight distribution on most dozers. There are some exceptions to this, but that is the general rule.
Jerry, I thought that would be the case. These machines are sure to be designed to efficently lubricate and cool the engine with todays technology. I understand the wear on the tracks and traction issue. Thanks.
Yep, what Jerry said. Never had an issue with my D5G and I have been on a few 1:1's.
I'm sure Cat has it covered, the old D8's had 3 engine oil pickups, front of the pan, center sump and a rear of pan. Not familar with a D3 but I'm sure if it's on its tracks and oil on the full mark you will be good.
A little refinement....the Old cats (dozers) actually had a front and rear pan pickup that dumped the oil into the center sump where it was picked up by the main oil pump. Just looking at a D3C unit parts book it only shows a single oil pickup from a sort of central sump.....but that engine is so short you can probably get away with it.
Yair . . . I tried to post here this morning but had a computer issue. This dropping oil pressure on a slope thing has been around for years. I can't comment on the newer stuff but in general most tractors won't back up worth a dam'n anyway . . . any slope that can be comfortably traversed up and down working seed in is never going to be a problem. In the real world I never found an issue. In a working situation the pucker factor cuts in way before there is any loss of oil pump prime . . . also it is very easy to watch the oil gauge when you're standing on the dash. I have dropped a few into breakaway gullies at some funny angles and we didn't have any problems. A problem could arise if a tractor had a cracked pump suction (as I have known to happen) . That is to say it works fine in normal operation but could concievably suck air if working on a slope. Cheers.
Interesting discussion. I must confess I've never thought of the oil pick-up issue. When I'm running something in which involves up and down hill, I always point the blade uphill for the simple reason that reverse is a slightly higher gear on my Fiat and she doesn't have the grunt to go up hill in the same gear as she can rattle down backwards in.
We learned the center of gravity (CG) effects the pucker factor.....on the little tractors is what I can report on (a JD350 and 450G) we figure the CG is toward the front due to engine and blade .....we have seen the tractor which was going straight upslope and maybe slipping the tracks a little bit, suddenly spin around until the blade was going downhill in a time period much faster than one can read this...how it didn't roll when the tracks were sliding sideways as it "clocked" on that slope is only because the downhill track didn't catch an edge....that operator was way gun shy after that as he knew he want wearing his seatbelt and if it had rolled he would probably be gone....from that day we very reluctantly drive steep upslope with the blade uphill plus we figure if the tractor were to start sliding down the hill it might be nice to stick the blade in whereas if the blade was going uphill it would only backdrag in this situation. A forestry service publication shows 75% slope max w blade going downhill and 55% max w blade going uphill (sorry no explanation for these limits)....ref: http://training.nwcg.gov/pre-courses/s232/S-232 Appendix D.pdf page 6 .....
backing up on steep ground is hard on undercaraige it puts a lot of stress on the front idlers and its trying to cramm all the excess track slack under the rear of the track frame instead of being able to let it hang between the support rollers. but sometimes you got no choice. never had a problem with the oil pick-up
We used to overfill the engine by a gallon and the transmission more than that to work on slopes. As far as I know Cat fixed this in later models. www.terrasmooth.com