Clinet's Lennox model # EL296UH090XE48C-03 furnace works fine on stage 1 heat, but hits the high limit switch when on stage 2.
The inducer sounds like it's blending nuts and bolts.
Can I upload a video of the inducer motor?
I would expect the pressure switch or even rollout switch to open before the primary limit, if in fact the inducer motor is the problem.
I would check second stage gas pressure and temperature rise which may indicate the primary problem.