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Code C0300 - Where is the Rear Propshaft speed sensor?
I have a 2010 F-150 XLT, only about 110,000 on it. The other day it pretty much broke down, (long story short it had some timing issues but that's not my problem right now) and the main issue was fixed. The mechanic who fixed it cant seem to find the origins of the problem that I keep having which is sometimes, the truck will drop its idle rpms and shudder, once or twice it has even stalled on me. I have an AutomendPro OBD sensor, and it gives the the code C0300, which says rear propshaft speed sensor. The only issue is, I cannot find it. Some forums/videos say it is on the outside of the transmission, others say it is in the lead case of the transmission, I've even seen someone say it is actually on the rear diff.
Is this a sensor I can fix on my own without cracking into the transmission, or should I find someone who can do it proper. I also have a 6R80 6-speed auto transmission.
Or, do you think this sensor isn't even the problem, and I should look elsewhere?
Last edited by greenlight25; Mar 23, 2026 at 06:48 PM.
