ok i sold my old rx7 and i bought a street port rx7, but now the problem is when i shift from second to third gear, the third gear grinds. does anyone have any ideas what it is or and solutions to fix it. out of all the rx7s that i have this is my favorite and dont want to get rid of it.

so if you can please help me i would gladly appreaciate it

 

Probably the third gear syncro.

Fortunately, n/a trans are super duper cheap. Find one in known good condition and replace it.

 

As the years go by, and the miles build up, the synchros can become clogged up with various bits of crud. One solution to try, before seeking a new tranny, is replacing the fluid with a 50/50 mix of gear lube (what you would normally use) and Auto Tranny Fluid. The ATF still provides plenty of lubrication, but also contains some really kick *** detergents that can clean that crap out of there and get things moving again.

This advice comes from "How to hodtrod and race your Datsun", and should apply to all Jap trannies of that era. I've been doing this for over 20 years, either as a cure for an issue or simply as a preventive measure, usually with good results and never with bad repercussions.

I have been advising people in your situation to try this for six years, and by the responses I'd say the success rate is around 75%. If there is a true mechanical issue, rather than a buildup issue, then this of course will not help. But for the cost of the fluid change, in both money and time, it is certainly worth the attempt....



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Interesting I haven't heard of that...

Is there a recommended time to then drain and fill with all gear oil?

 

Nope, you can run this mixture full time. It's all I use, in all my vehicles that have manual trannies....