I have a 99' Sedan LX VTEC with the 5-speed trans. I talked to my buddy whos a mechanic and he told me to get some fully synthetic transmission fluid so it would shift a lot easier (131650 miles on the odometer, still runnin' strong, YA YA HONDA). I went to AutoZone to get some and they told me 10W30 Motor oil was what had to be used!!! So i believed the guy and bought 2 quarts of CASTROL SYNTEC. Was motor oil a good choice??? If anyone knows any good fully synthetic tranny fluid, let me know. Thanks

 

ive read that some of the honda transmissions worked with basic motor oil, but you should verify this through your cars booket. Someone on this forum also said castrol syntec wasnt truely a synthetic oil, which i dont know if it true or not, but castrol syntec should be good if your trans actually can use it.

 

my booklet says that i should use Honda MTF (they just want to make a profit). they said that Motor oil can be used but "should change at earliest convinience). My mechanic said it should be alright though.

 

yeah, its always best to be safer then sorry, my friends grand am has a hydraulic transmission, he made the mistake of listening to one of the guys at advanced and put mtf in his transmission.... it reeeally screwed things up, he found out after the fact that he could only use syncomesh in it and using that fixed his problems..... for the most part....

 

you friend sounds like an awesome mechanic. you should ask him to join this site.....castrol is not a real synthetic oil...because of some loophole they are allowed to print that on the bottle.....i use mobil 1 green top (10w30) .....always....in my tranny and its the original one and i have 250 thousand miles on it......and upshifting or downshifting none of the syncros are even close to being worn out.

 

For what it's worth I switched mine to Red Line synth a week after I bought it......couldn't be more pleased. Did the same with the previous car and it made the notchy Mazda 5 speed a lot smoother and more positive shifting, regardless of the temperatures outside.