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Old 08-29-2005, 06:17 PM   #1
Join Date: Dec 2002
Location: Cheney, WA, US
Posts: 61

This is the new Fuller UltraShift LHP transmission. It is a 14 speed forward (13 plus an extra low), 3 reverse fully automated (2 pedal) transmission. I am not sure, but it appears to me that these transmissions use what is essentially a centrifugal version of a standard clutch. I am not totally enamored; I can't see much benefit over an auto-shift system with the three pedals.
The torque rating is also low; 1650, or an option for 1750 in the top 2 gears, to match the "top 2" technology of Cat and Cummins ("Smart Torque"). Unfortunately, the C15 and Cummins ISX easily hit 1850 foot pounds, so even if one gets a lower rating, it is not hard to turn up past the transmission's capacity. That's easily addressed if Fuller wants to - they have an auto-shift 18 speed rated up to 2250 foot pounds. Simply having a top 2 rating up to 1850 would have been easy and should have been done.
Considering that these 2 motors have a major advantage over their smaller stable mates (better engine braking), which really appeals to me, this transmission is a near miss for my plans. It's a staggering miss for an OTR truck, of course. *sigh* It may, however, appeal to a number of the readers here.
So, what is it? On its face, it appears to be an automated 13 speed, which some of you may recall is my preference due to the ability deal with varying speed limits around the country. The narrow split on top works better with the reality of speed limits varying from 55 to 75 without lugging, running in 9th (if you have a 10 speed), or revving too high at speed. It is not, really. I compared some of the ratios and splits, plus the fact that there is the extra low forward and an additional reverse. It appears that this transmission is more accurately a fully automated version of the 18 speed, with the splitter active in low, but not in 1-4 (the main gears of the low side). The top 4 gears then split as they would in an 18 speed. It not only automatically shifts, but skips gears as appropriate, etc. The 18 speed auto-shift does that, too, so it appears that this is a slightly feature challenged version of the 18 speed.
Myself, as it stands, I would stick with the 3 pedal auto-shift 18 speed, due to the ability to safely handle the better/stronger motors. If Cat puts the hydraulic retarder in the C13, we're good. Otherwise, it will be a C15 and the 18 speed auto-shift. So close, yet so far off.
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