lamboworld

I don't drive my car much in the winter, but I have noticed something strange the last few times I had it out. So here it goes.

The first time I shift into 4th gear it will grind and then go into 4th. It doesn't grind in any other gear and it only grinds the first time that I try to shift into 4th, otherwise it shifts great. All subsequent shifts into 4th are very smooth. My trans was rebuilt by Tick Performance last year and it shifts beautifully. I can drive my car around all day and it won't do it again. However, if I let it completely cool down or take it out the next day, it will grind going into 4th the first shift. Very strange.

I am going to try bleeding my clutch first and I am also going to switch the trans fluid to Driven STF. Any ideas?

Otherwise, I absolutely love my car at this point.

Dan_the_C5_Man

It sounds like fluid thickness / friction modifier / blocker ring incompatibility. You'd be surprised at the variables.

For instance, in my old C5 with a T-56, Redline MTL worked great.. In the current 6060, it sucked, and so did Royal Purple (RPM recommendation). Best I've found so far is Amsoil TD. Makes one wonder if stock fluid isn't best, just change it more frequently.

RamAir972003

If its the t56 its forgiving a couple of times the t6060 is not change thecfluids and check your pedal maybe its not engaging all the way.....

RichieRichZ06

Change fluid to Amsoil Torque Drive ATF and it will likely go away completely.

lamboworld

Torque drive is currently in it. I am going to switch it to Driven STF and bleed my clutch and see if that will fix it.

freddyvette

You could waste time doing that or just pull the trans and fix the synchros

lamboworld

The trans was just rebuilt and has less than 500 miles on it. Highly unlikely it is something mechanical inside the trans.

freddyvette

Denial is not a river in Egypt.

Seriously dude, I've rebuilt three of these. It's the synchro. If it was the fluid it would be doing it in all gears.

The dog teeth (when brand new) are designed to interlock when the fluid is cold while the coefficient of friction is lower. After the synchro rings get soaked and warm, they will become more grabby.

If the synchro is not grabbing the gear (ie slowing it down) when cold - that means there is either too much gap or the friction rings have been worn down / damaged during installation.

lamboworld

I hope that you are wrong, but you may not be. This rebuild is still under warranty so I guess it will get fixed one way or another.

freddyvette

There's just not much else it could be... anyone else who is experienced in rebuilding these, feel free to chime in here.

Dan_the_C5_Man

Who rebuilt it?

My bad, reading is essential - I see you did mention the shops name in your first post (or it does now anyway).

lamboworld

Tick Performance

https://www.tickperformance.com/tick...vette-z06-zr1/