The disaster lurking behind Jaguar’s 1988 Le Mans win

One more gearchange, and Jaguar's comeback victory would have been derailed at the 1988 Le Mans 24 Hours. The British manufacturer came that close to losing its first win in the French enduro since 1957 in the final hour. That the winning Tom Walkinshaw Racing Jaguar XJR-9LM lasted the course owed everything to the mechanical sympathies of lead driver Jan Lammers, and perhaps to some kind of sixth sense.

The Dutchman, who shared the victorious Jaguar with Andy Wallace and Johnny Dumfries, knew he had a gearbox problem as the 24 Hours drew to a close. He'd listened to team-mate Raul Boesel explain the demise of his own Jaguar in the small hours, as he tied his bootlaces before his stint in the penultimate hour. And when the symptoms described by the Brazilian appeared to be manifesting themselves right behind him, he took a bold decision that ultimately secured himself a place in the history books.

Lammers left the car in fourth and didn't touch the lever again - he didn't change gear from shortly before the end of his penultimate stint through to the end of the race. Thanks to the massive torque of the seven-litre Jaguar V12, he was able to continue at a decent lick in a gear designed to send the car down the Mulsanne Straight, then unsullied by chicanes, at 200mph.

What's more, he was able to clutchslip his way out of the pits after his final pitstop. It didn't matter if he damaged the clutch, he points out, "because I wasn't going to need it again".

"Raul said that he had been shifting from second to third, and it jumped out of gear," recalls Lammers, who was at Le Mans for the second time with the Silk Cut-sponsored TWR squad. "He then explained that he went to fourth, and it jumped out again, and when he went to fifth, he said, 'All of a sudden I had an empty 'box'. I went from second to third, and it jumped out. I went for fourth, and I expected it to jump out a second time," continues Lammers. "It didn't, and I immediately decided that I wasn't going to touch the gear lever anymore.

"I didn't know exactly what was wrong, but I'd had enough experience of preparing gearboxes when I'd been racing in Formula Ford 1600 to know how sensitive they could be. I just tried to make sure that I didn't put one jitter through the transmission."

Exactly how many laps Lammers did in this hobbled state isn't quite clear. Eddie Hinckley, who engineered the winning Jaguar, reckons the problem struck a couple of laps before his driver was due to pit. His run sheets suggest that Lammers did another seven laps after his final stop. So that's nine laps - or the better part of 40 minutes - in one gear.

Lammers knew that one false move could spell disaster: "I accelerated very slowly and when I lifted off for the corners, I tried to make sure that there was always a constant load going through the gearbox. I thought that if I accelerated or decelerated too quickly, the whole thing was going to fall apart."

Lammers was probably right. The main pinion shaft of the five-speed transmission, which had its roots in a gearbox developed by British constructor March for CART single-seaters in North America, had split in two at a point where an oilway ran through it. Somehow it was held together over those final laps by the splined hub that took the drive from fourth and fifth gears that straddled the break.

The chief mechanic on the winning #2 Jaguar, Rod Benoist, remembers the strip-down of the gearbox back in the UK after the race.

"As we took the gear cluster out, we saw that the main shaft had split in two," he recalls. "It was a case of scratching our heads and thinking, 'Thank goodness for that'."

"After we took the gear cluster out, we saw that the main shaft had split in two" Rod Benoist

Benoist thinks the chances of Lammers being able to select another gear were "about absolutely zero". Alastair Macqueen, the chief engineer on Jaguar's Group C programme, reckons that he could have selected fifth, but that it wouldn't have been a lot of use to him. Making it around the tight Mulsanne and Arnage corners, let alone getting going from standstill in the pits, would have been nigh on impossible in the higher gear.

The designer of the gearbox, Nick Wasyliw, reckons that any gearshifts both up and down with the broken main shaft would have been possible. He concludes that there must have been a second problem — possibly related, possibly not — that had precluded Lammers from engaging gears on his way up the gearbox.

"A strap assembly between third and fourth gears was a major part of the gearbox design," says ex-March man Wasyliw, whose Roni Developments company developed and serviced the transmissions for TWR. "It gave it massive strength both radially and axially, so that definitely played a part in holding it all together. Maybe the other problem was coincidental to the shaft failing."

But Lammers' role in securing Jaguar's first Le Mans victory in more than 30 years shouldn't be underestimated, reckons Macqueen. "Jan had brilliant technical sympathy," he says. "His part in that victory has been underplayed."

First, Lammers had to recognise the problem. Then he had to drive around it and keep up a decent pace. The Jaguar's lap times didn't drop away massively over the final laps, according to Hinckley. "Normally, the times would have been in the 3m26s and 27s," he says. "They went into the 3m30s straight away and, right at the end, down into the 40s, but such a drop wasn't unusual in those times for the final stages of Le Mans."

Lammers's ability to keep up a decent pace was crucial at a time when the chasing factory Porsche 962C shared by Derek Bell, Hans Stuck and Klaus Ludwig wasn't entirely out of the equation, despite a run of problems that began in the early stages of the race when Ludwig had to trickle back to the pits after running out of fuel in the Porsche Curves.

The Jaguar had been a lap to the good when Dumfries handed over the car to his Dutch team-mate, but there was some concern from the pits over the pace in the final laps. Lammers remembers being told "not to slow down too much" over the radio.

If Lammers's resolution to leave the gearbox in fourth was inspired, so too was his decision not to inform his team of his woes over the airwaves. Ludwig, the culprit for running the car out of fuel, would almost certainly have been able to put on a spurt in the works 962C. The Group C fuel formula gave each car a strict allocation and Porsche was much deeper into the black than its rival. Jaguar had just two litres left at the finish, whereas the Porsche had 21 of its 2550 litres remaining after 24 hours of racing.

"I didn't want to give too much away to our opponents, so I said, 'I've got a little secret for you'," explains Lammers. "They said that they didn't want to know, and I told them, 'You're right, you don't'."

The TWR Jaguar squad understood Lammers's 'little secret' as he left the pits in what patently wasn't first gear. That explains the Plan B concocted on the old Le Mans pit counter.

The three XJR-9LMs that finished the race assembled themselves in a formation finish over the final laps at the behest of the team. But it wasn't for the benefit of the TV cameras. It was just in case the leading Jag's gearbox finally gave up the ghost. "If the car had conked on the last lap, the idea was that one of the others would have stuck its nose into the gearbox of Jan's car and pushed it across the line," explains Macqueen. "I'm not sure how, because it wasn't something we practised."

Benoist confirms that there was some kind of plan to this effect in the works, though he also questions how it would have worked. "That was the kind of plan that Tom would have come up with, being the crafty old devil he was, and I think he was ready to implement it," he explains. "That's why we needed two cars there behind Jan, because the radiator in the nose would have been incredibly prone to the wing-support plates from Jan's car going right through them."

"The idea was that one of the other cars would have stuck its nose into the gearbox of Jan's car and pushed it across the line" Alastair Macqueen

Not that Plan B was communicated to the drivers behind Lammers. Derek Daly, who was at the wheel of the Jaguar run by TWR's North American operation that finished in fourth place, is adamant he was never told that he might be called upon to somehow push his team-mate around, just that he had to stay close behind on the run to the flag. "I don't remember that," says Daly, who was teamed with Larry Perkins and Kevin Cogan. "I don't doubt that it was discussed, but they would only have needed to communicate it to us if it suddenly became necessary."

Lammers wasn't impressed by the presence of the other remaining Jags on his tail as he tried to baby his car home. "I remember Jan telling us in rather flowery language to stop the other cars crowding him," says Macqueen. "He needed to do everything very gingerly - he was braking and accelerating so gently - that he didn't want other cars right up behind him."

The Jaguar didn't need a helping hand in the end. The only hand it needed was its driver's, to steer - but not to change gear.