i'm writing up this post as a compliment to n4ji's thread about his tranny not shifting smoothly. it sounds like a lot of n/a's have the problem of not so much grinding but just shifting slowly and with a lot of effort. appearently this is atributided to the synchros, but i'm no scholar on how transmissions work so im mostly just taking other people's word for it. if any one want to wigh in on the details of the relationship between fluid viscosity and synchro/transmission function it would be realy helpfull.

otherwise i'm just looking for sugestions on what lube(s) would improve this aspect of the transmission. i know some people swear up and down by synthetics and others recomend ofbeat additives but i realy just want to know what will make the shifts smoother.

obviously using stright up 75w90 like recomended by mazda leaves a little to be desired.

does a higher or lower viscosity help this problem? what chemical(s) will achive this ideal?

please weigh in with any advice/suggestions/knowledge you have on this subject.

 

i know some might say "dont shift to fast" or stuff to that effect but the problem is appearent even when shifting slowly and carefully. i dont think its so much related to abuse as it is the nature of an n/a tranny.

 

I am running moble 1 in my tranny right now. I still grind my gears but it help alot compairing to stock fluid. My friend is running red line he is also having good luck with it. But i since i didn't spend too much time driving his car i am not too sure.

 

Mobil 1 for me. Made a huge difference.
Still a bit 'notchy' tho, and of course, still grinds sometimes from the top of first to the bottom of second.

 

lucas tranny additive with 10w-30 oil. works wonders.

 

i think im gonna split the difference, go with 2 litters of 20w50 mobile 1(i think they make that weight?) and then top the rest off with lucas tranny oil. i hope it helps. at this point imwilling to get creative cus the slow shifts are realy staring to annoy me

 

I have the same problem with grinding and slow shifting. I am running Vavoline 80W-90 gear lube in mine and it is transfering OK but no great i will try the moblie and see, but with the grinding i have found the clutch isn't lining up right, while shifter is in "N" in mid shift release the clutch then reply. It helps a lot

 

I am a big fan of Redline products. I had some notchy shifting, especially on cold winter a.m.s and changed out to Redline and it shifts much better. I think it was ML90, would have to check again.

Fluids, and additives will not help if the syncros are really bad, but they do a great job for the money. Also check the shifter res. as a lot of times they are dry.