Alright, where to begin... I have a 2003 G35 sedan automatic 2nd gen with 213k miles. Within the past month, an issue has come to my attention. It started out as just fifth gear 'slipping' (that's the best way i think i can describe it). Basically it kind of went into neutral when i tried to accelerate slightly in just 5th gear at highway speeds. If i put a little extra foot in, fifth gear would catch and it would go. Then it got worse to the point where if i tried accelerating in fifth at all at highway speeds, it would just redline without accelerating at all. Now, currently, fifth gear does not work at all, at any speeds and fourth gear is starting to show signs of following suit. I was doing countless research and found out it might be a speed sensor going bad but i wasn't entirely confident in that seeing as other people with similar issues had a check engine light. I did not have a check engine light and the issue was getting progressively worse so i started leaning towards it being a mechanical issue rather than electrical. This was until i noticed my 'at check' light would flash at me several times everytime i started my car. So i decided to just hook a code scanner up and seen if i got any results. It pulled up code P1617 which i found out basically means the speed sensor is bad. Then the next time i started my car, the service engine soon light was on. So now I'm thinking it is the speed sensor. But that leaves me with a couple issues. Through research i found out the speed sensor is actually inside the g35's transmissions unlike their nissan counterparts the altima and maxima where the sensor is just right behind the front driver side's wheel. My first question is, has anyone replaced this on their own, is this a diy job? And if not, can I buy the sensor online and have just a transmission shop, who has the proper tools, replace the sensor for me? And lastly, can someone help me find the exact part number for this sensor for my car so I don't accidentally buy the wrong part? Any and all help will be greatly appreciated! Thank you.

 

Alright, where to begin... I have a 2003 G35 sedan automatic 2nd gen with 213k miles. Within the past month, an issue has come to my attention. It started out as just fifth gear 'slipping' (that's the best way i think i can describe it). Basically it kind of went into neutral when i tried to accelerate slightly in just 5th gear at highway speeds. If i put a little extra foot in, fifth gear would catch and it would go. Then it got worse to the point where if i tried accelerating in fifth at all at highway speeds, it would just redline without accelerating at all. Now, currently, fifth gear does not work at all, at any speeds and fourth gear is starting to show signs of following suit. I was doing countless research and found out it might be a speed sensor going bad but i wasn't entirely confident in that seeing as other people with similar issues had a check engine light. I did not have a check engine light and the issue was getting progressively worse so i started leaning towards it being a mechanical issue rather than electrical. This was until i noticed my 'at check' light would flash at me several times everytime i started my car. So i decided to just hook a code scanner up and seen if i got any results. It pulled up code P1617 which i found out basically means the speed sensor is bad. Then the next time i started my car, the service engine soon light was on. So now I'm thinking it is the speed sensor. But that leaves me with a couple issues. Through research i found out the speed sensor is actually inside the g35's transmissions unlike their nissan counterparts the altima and maxima where the sensor is just right behind the front driver side's wheel. My first question is, has anyone replaced this on their own, is this a diy job? And if not, can I buy the sensor online and have just a transmission shop, who has the proper tools, replace the sensor for me? And lastly, can someone help me find the exact part number for this sensor for my car so I don't accidentally buy the wrong part? Any and all help will be greatly appreciated! Thank you.