"Tranny slip times" I hear this term brought up all the time at a new pit I'm working at. What is the official name of this test? Referring to mainly dozers and graders. I'm sure it's just the jargon they use for a stall test but I'm not sure. Any ideas? Cheers
"Tranny slip times"? That's a new one on me. Like you say could be just a local term for the stall speed test. If you can get someone there to explain how they do it and what they measure it would be interesting to know. One could write a book, and I believe someone has, on the various regional terms for mechanical things. Just something that might seem simple like when someone says "Engine won't crank!", To that means when trying to start it the starter motor does not rotate the crankshaft. But I have heard people use that term when the engine is turning over just fine but will not actually run on it's own!
It might be clutch modulation time which IS adjustable. Whatever you do, don't try and do a stall test on a (Cat) grader. :|
Why?
Because there's no torque converter. They're direct drive.
Heck, give it a whirl and make sure the video camera is on. Actually several of them...... I'm curious to know what they're referring to myself.
All Cat graders? Even the new ones? again, why? I've only messed with old Cat graders, I assumed the newer ones would have TCs. Heck, my 1963 Austin-Western did.
Have absolutely experience with Cat graders and the newest grader I ever touched was an old John Deere 570! Any how did a quick look on SIS at the books on the Cat 24M an this is what I found:
Lol. Well done Ken on finding the one with a torque converter! But seriously kids, on anything from an 18 and smaller, don't try a stall test because you'll break something. *Challenges someone to find another one with a TQ and ducks for cover*
And that was just "The luck of the draw" I just looked up the first model number I found for a Cat grader. Maybe I should buy a lottery ticket?
Shift kit ? http://www.jegs.com/p/TCI/TCI-Trans-Scat-Valve-Body-Kits/2429659/10002/-1 Converter ? http://www.jegs.com/i/JEGS-Performance-Products/555/60461/10002/-1 I may be on the wrong thread ........
Not seeing any Cat grader applications there.
What machine is that chart from Mark? Don’t know if I’ld call it slip, but on our CCA 140H grader, there is an annoying lag between 4th and 5th, all others shift smoothly.
Powershift transmissions get a drag test, or a modulation test in the old days, these days they just throw a code, right? You don't want to slip them any longer than they're supposed to for a normal shift. The Cat's have powershift instead of torque converter for fuel efficiency, right? In the old days, a torque converter was a simpler functional transmission. Loaders still use a torque converter with reverser of some sort more than other equipment because of the back and forth short trip nature of the work. Graders run long enough distances that a torque converter isn't that helpful. I wonder if haul trucks use powershift only, or how many have torque converters.
Why no torque converter? I don't really know. You have to assume it's because of customer demand and resistance to change. Maybe it gives better control. Any operators like to comment? I'm sure that if Cat could pull a common TQ transmission from the corporate parts bin, they would. But then again, that countershaft transmission design has been around for so long, why change? Machines that travel any kind of distance, trucks, scrapers etc. have a lock-up torque converter. They're converter drive in the lower gears, then a clutch in the converter locks it into direct drive in the higher gears.
Each clutch control valve has an orifice to control the modulation. You possibly have a partial blockage.
I've heard a couple of different reasons from factory people and sales reps over the years for not having a torque converter. The first is the creation of heat when under load for a long distance. The second involves latching into a sudden load and the machine stopping while the torque converter builds more torque to overcome the sudden stop. I've worked on Cat, Komatsu, Champion and Dresser graders and don't recall any of them having a torque converter. I chuckled on the Cat 24 having one. I have always considered it more of an earth mover than a road grader. When you get to roads build for 100 or higher ton trucks I haven't seen where the road has to be as smooth as a tennis court.
Yeah I think it' just the terminology, still haven' found out but ill let you know when I do!
Hi Queenslander, the chart is generic to show slip times between clutch engagement I agree with Cmark, the orifices in the valve stations can clog up and cause what you are describing .also what can happen is if some one has had the valve stations out they may have been mixed up (some stations have different orifices in the body) Have you run the calibration procedure? mark
Yes, I once had Hast. Deering out to do 6000hr. service and had them do a calibration but it made no difference. We bought the machine at 5000hrs and countershaft seals had been replaced already.