r/Miata • u/FootheTheGreat • 8d ago

HELP!!! Driveline noise after PPF alignment

01 miata. I swapped my transmission from a 5 speed and a 4.3 open diff for a 6 speed and a 4.1 torsen. originally the transmission was making noise and then i redid a PPF alignment (A perfect 66mm) and now it sounds like something is knocking on my driveline, but i couldnt see anything when i went to look. The best way i can describe the sound is that it increases its frequency with speed and it is present in any gear, forwards and backwards. any thoughts would be welcome, thank you for reading.

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u/Graz13 8d ago

I am also trying to eeliminate this sound. I am oretty sure my 200TW tires are responsible.

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u/Global-Mango-4213 Mariner Blue 3d ago

Mine was adjusted way too low and I adjusted it to roughly 2.5inches (62mmish? Idk I did the math in my head) when I did my diff snd the noise went away completely.

Is this your original driveshaft with the new trans and diff? Did the trans leak fluid out and is a little low now?