I have a 1985 GSL-SE with about 119,000 miles on it. I had the differential fluid replaced about 20,500 miles ago at the suggestion of a Mr. Lube employee. I bought the car with about 79,500 miles on it and question whether the former owner ever had this done. The service manual calls for replacing the differential flluid every 30,000 miles. Is this something that fellow members regularly do?

I also noticed that the rear axle fluid should be replaced every 30,000 miles as well. I have never done this and doubt this has ever been done. Is this highly recommended? What is the incidence of rear axle seal problems on these cars? I have owned two 1979 RX7s in the past and had to replace rear axle seals on both of them, but never changed the fluid and the first car lasted me over 172,000 miles, albeit with a rebuilt engine.

Thanks

 

I changed mine about 300-400 miles ago.

 

Which did you replace calvinpaul - the differential fluid or the rear axle fluid and how often do you do it?

 

The diff fluid and I have only owned the car for about a year, but I try to change every fluid once a year. Of course that doesn't include the oil...

 

i changed mine last summer...prob not even 1000 miles ago...i was changing out rear bearings and tranny...so both were refreshed with new Redline fluid...good stuff!

 

Yes, change both gear boxes per the manual with light street duty. For racing or hard driving I would replace it annually. Change it with a high quality synthetic lube.