The Grove Racing driver prompted the only caution of the race when his Mustang was left stranded trackside at turn 9.
There was no broadcast footage of what happened, although subsequent TV pictures showed that the car was damaged.
Reynolds has now revealed that the issue was a front suspension failure that led to a monster crash.
The impact with the wall was measured at 38G, Reynolds emerging mostly unhurt except for some tenderness around his crotch straps.
"I was driving up to turn 9 and something felt funny, like there was some pick-up on the tyres," Reynolds told Motorsport.com.
"I gave the wheel a shake and nothing fell off, so I pressed on. I turned into turn 9 and something broke on the front end and it turned me hard left into the fence.
"Something in the front right failed. Initially I thought it was front left because of the way it turned me into the fence. I'd had some contact with people earlier in the race that could have led to something breaking later.
"I don't think I've hit the fence that hard in eight or nine years. It was fast and quite scary because the wall comes out at the track.
"Initially my nuts hurt, but I'm not worried about that. My missus says I don't need them anyway."
Repairs went well into the morning hours as the crew fitted a new rear clip to the Penrite Mustang ahead of today's second race.
"5am they got home," said Reynolds. "I can't believe the work they put in, it's a mind-blowing effort.
"They replaced the rear clip and the work that goes into that... it just takes so long."
