IVRedZ28LS1

iTrader: (3)

I was wondering what could be causing this grind in 4th gear while at WOT. I 98 camaro Z28 6 speed t56 with a pro 5.0 shifter with the adjusting stops adjusted the right way and has Royal Purple Syntheic fluid in it. It would only do it why the vehicle was cold and I would shift it pretty quick into 4th gear while driving it under normal conditions. Once the fluid warmed up the problem was gone. NOW IT IS DOING IT ALL THE TIME AT HIGH RPM ONLY WHEN I'M RACING MY CAR AND SHIFT IT INTO 4TH GEAR PRETTY QUICK. The grind is there every time I shift at wot or hight rpm when racing, but when you drive under normal conditions it does not grind at all. 4th gear works fine, it does not pop out or anything but grind only when being shifted into 4th gear only. HELP PLEASE. DO I NEED A REBUILD the T56. OR WOULD CHANGING THE FLUID BACK TO GM SYNCHROMESH WORK? HOW ABOUT THE ADJUSTING STOP ON THE PRO5.0 shifter causing the problem? DO I need to back off the adjusting stops on the PRO5.0 shifter. Thanks guys for your help. I DO SEEM TO MISS GEARS LATELY FOR SOME REASON NOT ALL THE TIME THOUGH. BENT FORK?

Domestic Demon

iTrader: (1)

Definitely sounds like the sychro is going bad to me. You say it shifts normally under regular driving, so that means the clutch and shift forks most likely aren't causing the problem. If the clutch was bad it would grind in other gears besides just 4th, and if it was the 3-4 shift fork it would grind at different RPMs regardless of how quickly you shift.

Don't bother changing the fluid to Synchromesh. The trans is designed for Dexron III ATF, if you have RP synthetic ATF in there then thats the best you're going to do. My synchros are getting worn out, and even with a fresh fluid change and Lucas "Trans Fix" additive it still grinds just like before.

The bump stops aren't the cause unless the stop is adjusted too far forward and itsn't letting the shifter go all the way into 4th. Screw the bolt in farther and see of it helps.

My guess is its the synchros though.

Hope that helps.

IVRedZ28LS1

iTrader: (3)

I forgot to mention I have already upgraded the Slave cyclinder, McCloud Adjustable Master, performed the Drill Mod and Has a SPEC 3 clutch in it when I did the Cam install in FEB. of this year. It all has about 6,000 miles on it. I recently installed heads on it about 5-6 weeks ago.

IVRedZ28LS1

iTrader: (3)

Can anyone help me? please. Yesterday I changed the tranny fluid. I drained out the Royal Purple and put some fresh new Dexron III ATF fluid in my T56. DRiving it around. I have not yet got on it and see if it grinds at high RPM when shifting from 3rd gear to 4th gear. THis moring when I was driving it normal and I shifted quickly in to 4th it grinded a little though while the car was still cold. But once it warmed up it didn't do it at all with Dexron III fluid.

Domestic Demon

iTrader: (1)

Like I said above, sounds like the 4th gear synchro. Mine does the same thing, if the trans is cold and you shift it quickly, it will almost always grind. As the fluid warms up, the grind doesn't happen as often.

Unless you want to have the trans rebuilt, theres nothing you can really do about it. Just take it easy on the trans, once it gets to the point where its a constant grind or other gears start grinding badly, take it in for a rebuild.

IVRedZ28LS1

iTrader: (3)

Thanks Domestic Demon.