Four days on the Gros Ventre with a leaking rear main

Getting there

The forest road turns off the highway at a cattle guard with no sign, which is the first useful thing about it. Twenty-one miles of graded gravel that deteriorates in three distinct steps: fine for anything with clearance, then washboard bad enough that you either drive it at 8 mph or 35 and nothing in between, then a mile of embedded rock that had me out of the truck twice picking lines.

We aired down to 22 psi at the cattle guard and it transformed the middle section. I keep re-learning this lesson and I keep being surprised by it.

The leak. I'd noticed a spot on the driveway two weeks earlier and decided it was "probably the transmission pan gasket," which is the kind of diagnosis you make when you want a specific answer. It was not the pan gasket. By the second night the drip had become a stain the size of a dinner plate under the bellhousing, and I spent an unreasonable amount of the trip checking a dipstick by headlamp instead of sleeping.

Four hundred and eighteen miles is a long way to drive to be outfished by an insect two millimetres long.

The water

At 212 ft³/s the river is bones-out. Every structure that matters is visible from the bank, which sounds like an advantage and is actually the opposite — if you can see the fish, the fish has been watching you since you were forty feet upstream.

They were pinned against the far bank, in the two feet of shade under the willows, and they were eating something I could not identify for most of Friday. I ran through the whole confidence box. Parachute Adams, refused. Purple Haze, refused. A #18 Sparkle Dun got one genuine look and then nothing.

Saturday morning I finally got low enough to see what was actually on the water: grey drakes, most of them dead or dying, drifting flush in the film rather than riding up on their legs. The fish weren't refusing my pattern's colour or size so much as its posture. A cripple in a #20, greased only at the wing and fished on 6X, got eaten on the third cast and then eleven more times before the light went off the water at four.

Camp

Dispersed site on a bench about sixty feet above the river, flat enough that I didn't level the truck, with a stand of aspen on the windward side that turned out to matter on the second night. It dropped to 27°F. The water in the jerry can had a skin of ice on it by six in the morning.

No fires — stage two restrictions were still on. Cooked on the two-burner, went to bed at nine like a person with no imagination, and slept extremely well apart from the dipstick expeditions.

What I got wrong

• The oil leak. Obvious in hindsight. I had two weeks and a lift shop eleven minutes from my house, and I chose optimism. It was a rear main seal. It cost four times what it would have cost to catch early, and it very nearly cost me the trip.
• I fished too high in the column for too long. A full day burned on the assumption that a visible rise means a fish eating on the surface, when a flush-floating spinner produces a nearly identical rise form.
• Only one spare tippet spool of 6X. On low, clear water in September, 6X is the whole game, and I nearly ran out on day three.

Would I go back

Yes, and at almost exactly the same date. The trip works because of a narrow overlap: the road is still dry, the flow has dropped enough to concentrate fish, and the drakes are still coming off. Two weeks later and the first storm makes that road a genuinely bad idea in a heavy truck.