Which range?

   / Which range? #1  

avorancher

Silver Member
Joined
Jul 29, 2003
Messages
215
Location
Deluz, CA
Tractor
Kubota B7800, RTV900
I've been moving 25 tons of gravel down a long hill with my B7800. I back all the way down in reverse with a full FEL. It keeps the front wheels on the ground and the gravel in the full bucket. (loaded rear tires and a BH for ballast)

My question: When returning empty, I can use the mid-range gear and keep the HST full open. But if I use the high-range, I have to feather the HST pedal in some places and even stop and shift to mid-range for a small section. The nice thing about high-range is that I can make the 8 minute trip in much less time...and I'm making a lot of trips.

Time isn't as important as not damaging my new B7800 however. Is there any possibility of damaging anything if I use high? Sometimes, I can smell what seems like burning oil when I do the feather techniques, so I've been just using the mid-range speed and enjoying the scenery pass by ever-so slowly.
 
   / Which range? #2  
I used much the same technique while using my L48. I don't believe there will be any damage to the HST by feathering it providing it is not allowed to get so hot that the transmission cooler cannot adequately cool the hydraulic fluid used by the HST. When you say burning oil, I cannot imagine the HST getting that hot from the use you describe. Even on a very hot day and pushing loads with my tractor in either M or L range, it's difficult to get the fluid that hot. I have instances where the HST in medium cannot turn the wheels, a condition that will happen while pushing a pile and loading the front tires. I still don't get any burning oil smells. Do some experimenting. Try the high range the way you have been and smell the oil at the dipstick. If possible, take a temperature check of the oil. I use H routinely on my L3830, it works exceptionally well. Quite frankly, far better then my L48.
 
   / Which range? #3  
avorancher
I moved 50 FEL buckets of topsoil about 1500 feet this summer with my B2910. On the run back empty, I would use high range. To control the tractor up a hill I would back off on the Hydro pedal. Found that running engine at PTO speed helped to cut down on lugging of engine on the hill.
It is not uncommon for the temperature of Hydro oil to exceed 180 degrees when used hard.
When running a crossed some rough ground when empty I used FWD. This gave better control of tractor.
 
   / Which range?
  • Thread Starter
#4  
Thanks for the responses. I'll give the "smell test" a try this weekend. I guess I have to stop thinking that HST is like a slipping clutch, and think of it as a pressure valve instead.

By the way, the B7800 is nearing the 50 hour mark and it has exceeded my expectations on all accounts. I'm amazed at what I can do with it. :)
 
 
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