Whilst you may not have heard of Allison Transmission, if you’ve ever travelled in a bus then it’s quite likely that you have been in a vehicle using their fully automatic gearbox.  The company was founded in 1915 by James A. Allison and originally produced not gearboxes but aeroplane engines.  From 1929 and for almost 80, Allison was part of General Motors but was sold to present owners Onex Corporation & The Carlyle Group in 2009.

Allison is by no means a small company either, with over 2,900 employees and 1,500 distributors worldwide.  Product-wise you can find one of the over 5,000,000 transmissions that the company has sold in vehicles as diverse as dustbin lorries, buses, fire engines, dock ‘tugs’ and the American M1 Abrams Battle Tank.

But, as they say, the proof of the pudding is in the tasting which is why TNN found itself at the aforementioned quarry, behind the wheel of a Volvo FH16-660 equipped with an Allison 4700 series gearbox.  

Normally when manufacturers invite journalists to try their wares, the vehicles we’re given are from their pampered press fleets but not this time.  The FH16 in question was an 8x4 heavy hauler tractor unit owned by Wallners Specialtransporter.  The owner, Mikael Wallner, had bought his truck new and then taken it straight to Allison Transmission Nordic in Bollebygd to have the gearbox he wanted fitted.

Wallner’s carry items such as components for wind turbines, and need to have smooth, uninterrupted shifting (characteristics of the Allison product) when climbing steep hills and also going off-road with these heavy loads.  “With automated manual transmissions (AMTs) and manual transmissions, the engine pauses to allow each shift, stalling the vehicle’s forward momentum and losing power” says Mikael Wallner.  In addition, he praises the fact that the Allison does not allow rollback on steep inclines and points out that “On a slope the dry clutch of an AMT can slip with its typical smoke and smell.  If worse comes to worst, the clutch can even catch fire.”

Fitting their 4700 series into the Volvo did present a couple of issues.  Firstly that the 4700 is designed to take 2,500Nm of torque, and the FH16-660 generates 3,100Nm and secondly where to put the gearbox controls in the cab.  Speaking to one of the Allison engineers, TNN learnt that whilst they were confident that the transmission would take the extra torque, locating the controls took a bit of work, as ‘Volvo can be quite particular as to where you put stuff’.  

Whilst he was happy for us to drive his truck, Mikael understandably wasn’t going to let us test with one of his customer’s loads on the five-steering axle Goldhofer trailer that was attached to the FH16.  Therefore, our load was a Caterpillar articulated dump truck that had been loaded with gravel to give us a gross vehicle weight of 105.4 tonnes.  Now this was more than heavy enough for us, but is almost light compared to the 280 tonnes GCW that the Volvo can and has pulled.

Sitting in the passenger seat as Mikael drove down the muddy road from the quarry’s (normal – more on that later) highest point to the entrance, the mile or so of 18% slopes and hairpin bends gave us time to admire both the machine and the skill of its driver.  Negotiating the entire downhill sections using nothing more than the integral retarder was a powerful demonstration of what good equipment combined with a highly competent driver can achieve.

Having turned round at the entrance, but before we switched seats, Mikael had one further party piece to show off.  Stopping halfway up one steep section, he applied the handbrake, allowed the revs to rise to a little over 1000rpm and then released the brake.  With perfect poise and no judder or rollback, we gently moved off once more.

Having seen how the professionals do it, the time had come for TNN to give it a try.  We set off in normal ‘drive’ and when we reached the base of the hill climb section we stopped, locked the gearbox into that extra-low first (7.63:1 as opposed to 3.51:1) and began to climb.

As we reached the summit, it dawned on me that throughout the ascent the only thing I’d really had to pay attention to was allowing for the steering Goldhofer trailer.  The mighty Volvo had provided all of the pulling power needed and the Allison ‘box had made sure that that power reached the wheels in a controlled manner.  In fact, given the ease with which the climb had been made, you’d have almost been forgiven for thinking we’d been driving along the motorway and not up a twisting, muddy quarry track.

Back on level ground, we engaged ‘normal’ drive and left the gearbox in charge of selecting the right gear.  No surprises that this is a job that it is, of course, extremely adept at.  

TNN cannot stress enough just how impressed we were with the Allison gearbox.  Whilst we have driven some big trucks before, the 105 tonne GCW in this test was over twice as heavy as anything we’ve ever tried before.  However, we might as well have been in our car such was the ease of driving.

So, having had it proven both to us and by us that an Allison Transmission is a perfect solution for a heavy hauler, it was time to look at some ‘smaller’ vehicles…

The following day found us back at the quarry where the team from Allison Transmission Nordic had also provided three other trucks for us to try; a 6x4 Volvo FE-320 Tipper, a Scania 6x4 P380 Tipper (both loaded to a GCW of 26 tonnes) and a 6x2 Scania R480 with a rear steering axle and Istrail tri-axle, long drawbar trailer with a combined GCW of 50 tonnes.

Thanks to the reduced size of these trucks, yesterday’s ‘high point’ was no longer the highest and we were able to venture even further upward and into the quarry along tracks that were simply too narrow and tight for the FH16.

The FE320 and P380 both drove very well, with their Allison gearboxes (3200 series for the Volvo and 4500 for the Scania) changing smoothly and deftly into what always felt like the right ratio.  The integral retarders on each provided confidence inspiring slowing without the need to use the brakes - although covering them (and gentle use of the same when necessary) is always recommended on steep descents.  

Whilst nowhere nearly as revelatory as the big Volvo had been the day before, the benefits of a top-notch automated transmission for vehicles of this type performing on and off-road duties were clear to see.  If nothing else, from a safety perspective leaving the driver free to concentrate on his surroundings makes the Allison a worthwhile investment.

Of the three trucks we tried, the 6x2 Scania was the most astonishing.  Looking at some of the slopes that had a gradient of at least 20%, you would have thought that there was simply no way that a two wheel drive truck would make it, leave alone one with a trailer and up at 50 tonnes.  But once again the Allison enabled what looked impossible to become not just possible but easily possible.  

As on the previous day, most of any potential worry was spent making sure we’d chosen the right line for the trailer, not on whether we had enough traction or what gear we were in.  Some of the tracks we were negotiating were only a few feet wider than the wheelbase with drops of over 80ft available should you get it wrong and we certainly weren’t interested in testing the build quality of the Scania.

With our confidence levels up, we even tried a hill start or two.  Handbrake on, get to 1200rpm, release brake and another no drama manoeuvre completed.  No matter how steep or slippery the slope we tried this on, each time we moved off again without any trouble at all.

Now TNN’s praising of the Allison gearboxes we tried is all well and good, but what did the people who deal with trucks day in and day out think?  Perhaps the most ringing endorsement came from the quarry’s owners.  They and Jan-Erik Eskilsby, Area Manager for Allison Transmission Nordic, know each other well, so when Jan-Erik asked if he could use their quarry for the two days, the company were happy to help.  During the conversation Jan-Erik explained what would be taking place and where, exactly, he wanted us to be able to drive the demonstration trucks.  The quarry owner’s response, ‘you won’t get a truck up there’.  As was proved several times, we could and very easily.

This article started by asking whether there was a place for Allison’s products in a market where the manufacturers themselves provide automatic and semi-automatic transmissions.  Simply put, it is our belief that if you want the best automatic transmission available with all the benefits that it brings, then you will not do better than the Allison.  There is, however, one potential fly in the ointment and that is the cost.

Somewhat understandably, the major truck manufacturers would prefer you to have their own transmission offerings in one of their trucks and so charge a premium for fitting the Allison unit.  A notable exception to this is a derivative of the Renault Midlum specifically for the Pick Up & Delivery sector, whose initial specification included the Allison gearbox.  However, if the vehicle you are considering is of high value (and what premium tractor unit isn’t these days) and intended to have a long working life, then over the course of your ownership the additional cost is only small month on month.

That said, TNN suggests that you might take an alternative approach.  With the economic climate being what it is we think, that if it has any sense, the main dealer network would be wise to see ‘what it can do on price’ when it comes to your request for an Allison.  TNN knows – we’ve seen the figures – that there is room for movement despite what they might tell you.