I'm having some serious issues shifting at high RPMs. I have an OS Giken twin-plate clutch using a new OEM throwout bearing(I have heard that your supposed to use a Mazdaspeed TO bearing, but have also heard OEM works fine) and a Mazdaracing short throw shifter kit and ****. Brand new clutch master and slave cylinders with a braided clutch line. I'm using Valvoline gear oil(75 weight if I remember correctly, but it might be higher).

When I try to shift at 7000+ RPM, the shifter often will not go in the gate. This happens in 2nd, 3rd, and 4th. When it happens, it will not go in no matter how hard I pull on the shifter, but will go in after the revs drop to 5-6k.

A few older more experienced car nuts I know told me that I need to use a much lower viscosity oil in my trans, and the problem will clear up.

Does anyone have any experience with this problem? I've been running a high viscosity gear oil in my trans since I got it, and don't ever remember having this much of a problem.

 

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are you low on fluid? might want to check that. that will cause it not to go into gear. trannys call for 75-90 or 80-90 fluid so your fine

 

i had a 1st and second gear problem and used gm syncromesh and all is fine now

 

I've started to have shifting problems. Of course the clutch pedal is causing the clutch to engage pretty low to the floor. Acouple of day's ago it actually died at a stop sign and then refused to go into first (or any gear), afterI restarted. Luckily I was on a slight down grade and when I started coasting to the side of the road, it allowed me to slip it into first.

I know *little* about clutches and transmissions. It has a Act 6-puck clutch. I'm going to put it on stands and crawl under to take a look next week.

What is there to check and adjust? Anyone have thoughts that might help direct my looking? Are there any forums or web sites where I might find information?

 

Yea, GM syncromesh is what they recommended as well. As for the trans oil being low, I doubt it cause I filled it not too long ago and it doesn't leak.

Will switching to a lighter weight oil hurt anything?

 

worn transmission, probably

 

I use royal purple 75 90 in my na, it cleared up all the notchyness I once had. Check if there is any play in your shifter. (i.e. can you move it up and down) Worn shifter bushings are a possibility even it your shifter is fairly new. If there is no play in the shifter and synthetic gear oil doesn't clear up your problem then a rebuild is your only solution.