Allison’s new TC10 twin countershaft 10 speed automatic has broken cover in Australia and David Meredith got the chance to drive the new prime mover transmission in Brisbane during the recent truck show and here is his report for www.truckandbus.net.au
The Allison Transmission company is not into inflated statements or unrealistic promises. In fact, the company is quite subdued and tends to downplay performance data for its products. Perhaps “under-promise and over-deliver” applies here. So I was surprised when I got hold of a technical brochure on the company’s new TC10 dual countershaft fully automatic transmission.
On the front page is the statement, “Allison’s TC10 delivers 5 per cent better fuel economy.” It follows up on page two with this – “the TC10 achieves the best fuel economy, regardless of driver experience or expertise.” Neither statement has an asterisk or footnote that references a lengthy and incomprehensible disclaimer crafted by overpaid lawyers. It’s just claim one, and claim two – that’s it.
Any half-decent fleet owner reading this knows his or her fuel bill for the month and year. So it begs the question, just how much cash is that five per cent worth to you? Given that a dollar saved is a dollar earned, and we’re not exactly in prosperous times, the claim deserves a very close look indeed.
I first heard about the TC10 a couple of years ago as it was being released for evaluation in the US. Allison boxes reign supreme in vocational work with an unmatched record for reliability and driver ease. Indeed one of our big Queensland concrete fleets was asked why Allison was its preferred transmission. The answer was just two words. “Zero downtime.”
TC10 promises to take the advantages of constant torque to the line haul business, presently dominated by Eaton’s 18-speed manual Roadranger and a host of pretty tricky automated manuals. Cost was a perceived problem, as was the diminished advantages of the auto on long-distance cruise.
So when Allison extended an invitation to me to be the first Australian journalists to drive the TC10 on home soil I was keen to take up the offer and drive the new 10 speed auto which has been fitted to a Kenworth T359 working as an interstate car carrier. The evaluation wasn’t so much a reliability test as it was a test of local acceptance. It’s been on sale in the US now for almost two years – that’s how Allison makes the fuel economy claim – so development testing is well and truly completed.
Prixcar Services is owned by Toll and the K-Line shipping company, and runs a fleet of car carriers all over the east coast. Its newest Kenworth 359 had been delivered with an Eaton Ultrashift Plus behind the Cummins ISM 11-litre engine. Allison converted the driveline to the latest TC10 before the truck even had its first run. The intention was to prove in the real world how the new TC10 box compares with manual and automated manual transmissions.
Car transporting is a specialised business and requires its own unique practices compared to bulk, containerised or general van transport. That became obvious when regular driver Martin Eales briefed me before my test run in the Prixcar rig, which was loaded with seven new cars on its flat pack two-deck car trailer. He clearly had concerns about the welfare of his load as he handed over his truck. “Watch for overhead. I don’t want a Honda with a tree branch sticking out the front,” Martin smiled.
Dave Gordijn Allison’s newly appointed customer service engineer in Australia chimed in to warn me about the high centre of gravity as well.
I’d always assumed that car carriers were the equivalent of container skeletons and were pretty light. However the Prixcar trailer weighs in at 22-tonnes empty, due largely to the engineering of the side frames which have to support the entire top deck when it is ifted at least two-metres in the air and fully laden with valuable automobiles. The lifting system means drivers no longer have to climb up onto the trailer’s top deck to secure the cars. Just drive on, step down to the road surface, lash the wheels down and raise the platform. However when you add seven vehicles including a handful of hefty double cab pick ups, then the truck is operating pretty close to maximum GVM.
The TC10 is Allison’s first twin countershaft transmission and is designed to combine the undoubted advantages of a full automatic thanks to the torque converter in stop-start manoeuvering work, with the benefit of ten speeds to deliver enough ratios to cover the demands from start up to long distance cruising speeds with a tall enough top end to ensure low engine revs at the top end. The torque converter helps here as well because it multiplies the torque at start up which means the final drive ratio in the diff doesn’t have to be as low as in a manual ten speed meaning lower engine reves, less wear and lower fuel consumption.
Being a self-confessed fan of full automatic truck transmissions over the wanna-be AMTs, the TC10 is a product I have been eagerly anticipating for some time. The ten speeds are evenly spread to a direct drive ninth, with tenth gear being a 0.86:1 overdrive. The gearing spread allows this Kenworth to use 3.08 diff, bringing highway cruising rpm down to a lazy 1,350rpm. The methodology is pure Allison – a torque multiplier, or converter, is used for take-off, and then the transmission locks up, with changes happening using wet clutches to maintain full and uninterrupted torque from start to top speed.
The initial lock-up on the TC10 occurs at walking speed, so there is no torque loss under power and always enough wear-free torque for take-off, even under full load and on the steepest slope. All of this means two critical things for Allison owners. Firstly, with uninterrupted acceleration as the transmission changes gears, every drop of fuel goes toward driving the truck down the road. Secondly, there is zero friction wear on take-off, crawling and reversing, and every launch is smooth. Both factors are critical to this application, particularly with the high centre of gravity, so on the surface the transmission appears to be tailor-made. Certainly Martin Eales thought so. His comments were glowing and he confirmed that the fuel efficiency of the truck is several percentage points ahead of the AMTs he has driven during his many years of experience.
My drive was not long, but it was in and around light industrial areas, as well as tackling some hills, so the transmission got a pretty good workout. The engine was never under stress as the software kept the rpm in the right torque range as low as possible to meet whatever demands I was making of it. The Kenworth T359 is an ideal rig for this task. A tight wheel cut meant better than average turn in, so I never had to use all the road at intersections.
When I got back, Dave Gordijn from Allison showed me a feature on the Allison selector module that I hadn’t bothered to check out during previous Allison drives. Holding down the manual shift buttons together for a couple of seconds turns the small display into diagnostic mode, revealing oil temperature and oil level in the transmission. They are two critical checks a driver can do without getting out of the cab and raising the hood, and will be well received.
In the briefest possible terms, the TC10 lives up to every one of Allison’s claims.
At this point the TC10 is rated to 600hp and 2,305Nms, but for single trailer use only. Heavier ratings will arrive as local experience is gathered according to Allison executives. Truck manufacturers will do well to get on board with this new Allison transmission and start the process of planning for the digital communication required between their engines and the TC10. At this stage, retro fitting the TC10 to an existing rig is the only possibility in Australia, but if I were in the market for a new single trailer multi-purpose prime mover, I’d be asking questions of the manufacturers about the availability of the TC10 in their ranges when starting the buying process.