Fixing Gear Grind/ Shift Issues w/ upgraded syncros and master cylinder

[esperman]

The V8's don't have our Aisin tranny. FLUSH that ATF out and put in gear oil. ASAP.

Originally Posted by djrasras

You're right about the master cylinder upgrade- I wasnt thinking

Just curious, why is D4 ATF bad for the synchros. I guess I didn't do enough research; I went back and saw that the guys on c5 who have recommended Redline ATF have v8s, not v6s- does that have anything to do with it? I havnen't put many miles on the car since doing the tranny fluid change, so if its a big deal I can definetly swap it out for 75W-90 this weekend.

[djrasras]

Originally Posted by Ventmaster

That's a definite YES- Royal Purple 75-90w gear oil in the manual trans (no automatic trans fluid for the V6) and an Ideal G clutch master cylinder. I tried multiple trans oils in the V6 and RP was my last pick (AMSoil, Redline, Motul, you name it) and proved to be the best. A separate reservoir for the clutch and DOT4 (Motul 600) also improved things a great deal.

However, if the sychro's have received too much abuse, no amount of TLC will bring them back... I never heard if any upgraded 2nd gear synchro's were approved for the V6. That sort of thing got reserved for the V8's!

Good luck!

Got it, I bought this car used and the grinding has been bad from day 1; 4 years later it hasn't gotten any worse, and I've done everything I can except for a tranny rebuild and master cylinder upgrade. I'll go back to RP fluid, and will do the MC upgrade soon, but from what I'm hearing it looks like I should get the synchcros replaced before I cause more internal damage. How much should something like that cost? And if I'm already having the mechanic open up the tranny, are there other upgrades I can do to it to increase its life/performance?

Thanks everyone for the assistance so far.

[djrasras]

Originally Posted by acammer

For my car, I think the ultimate issue was that the Hurst shifter had very worn bushings - causing an incomplete/weak push from gear to gear. Without sufficient pressure the syncro couldn't do it's job, it so it would grind or lock out.

I'm not sure if that helps, but I thought I'd share my experiences with a similar problem. It was extremely frustrating, making me doubt my own driving at times. The relief and joy I now get driving the car makes all the chasing worth it.

Wow thanks for the thorough response, your video really captured the difference between shifting after those upgrades. Honestly, I gotta say that I'm definitely in a similar boat, as upgrading to my Barton Short Throw made the grinding worse. I thought I installed it wrong, so I went back to stock and had my mechanic install the Barton the same time he was doing my clutch, and ya, still had worst grinding. Because I had spent both time and money installing the shifter twice, and liked the look of it, I kinda just kept it and figured I would try to see if there is another root to the problem. But one thing- you kept mentioning worn bushing on your shifter- could that really be an issue for me if the shifter assembly was new when I installed it?

[acammer]

Originally Posted by djrasras

Wow thanks for the thorough response, your video really captured the difference between shifting after those upgrades. Honestly, I gotta say that I'm definitely in a similar boat, as upgrading to my Barton Short Throw made the grinding worse. I thought I installed it wrong, so I went back to stock and had my mechanic install the Barton the same time he was doing my clutch, and ya, still had worst grinding. Because I had spent both time and money installing the shifter twice, and liked the look of it, I kinda just kept it and figured I would try to see if there is another root to the problem. But one thing- you kept mentioning worn bushing on your shifter- could that really be an issue for me if the shifter assembly was new when I installed it?

I don't think a worn bushing would be the problem if it did when newly installed. Probably internal trans damage, unfortunately.

[djrasras]

Originally Posted by acammer

I don't think a worn bushing would be the problem if it did when newly installed. Probably internal trans damage, unfortunately.

I feel like I am at the point where it would make more sense to swap the tranny then to rebuild. My questions is, should I swap with another GM stock tranny, or are there any transmission upgrades available?