goturgoat

iTrader: (1)

My T56 in my 06 GTO has been giving me some trouble going into 5/6 gears. The problem is specific, when shifting out of fourth at around 85+ it just blocks the shift. I am not really sure what the issue is. In all other gears up to redline it shifts normal. I have a RPS street twin, Hurst shifter and the rest is stock. I'm thinking either the 5/6 pack is messed up or the drive shaft is out of balance and is shaking the output shaft. Any other opinions/solutions would be great.

85MikeTPI

iTrader: (9)

It only happens at 85mph+ ? No problems at lower RPM or with the car shutoff? Can you go right from 4th to 6th at that speed?

If so, then it does sound like your 5th gear blocker is gone bad, or the 5/6 fork if its happening in both.

goturgoat

iTrader: (1)

No problems at lower speeds or with the car shut off. I honestly figured I would have killed a 1-4 gear before the 5/6 pack.

85MikeTPI

iTrader: (9)

Have you checked the fluid level in the trans lately, or replaced it? (how many miles on the trans?) Since the 5/6 synchro cluster is constantly bathed in fluid, any contamination could affect it sooner/more-so.

goturgoat

iTrader: (1)

well took the end bell off the transmission last night and found nothing at all with the 5/6 gears. though it does seem to have a bit more resistance when put into 5th and spinning the input shaft. synchros on 5/6 look nearly new and the forks appear to be straight. the oe fork pads are intact. I barely found any metal on the magnets, not bad for 15k of abuse. still confused and agrivated that I cannot come up with a solution. at a minimum I am going to replace the pilot bearing, slave and drive shaft to eliminate mis-alignment/hydraulic issues. Any other ideas???

85MikeTPI

iTrader: (9)

You can't really test double/triple syncros by looks.. You need to clean them, paint the metal friction surfaces with machinist-blue, and rotate the synchro on the gear. If the wear pattern isn't fully removed from metal, there's probably wear on either the synchro or gear.

Any other word on the fluid ? (type, age, temperature in your area)

goturgoat

iTrader: (1)

Fluid was basic dex III which was clean as can be, roughly 1 year old and the temp can range from 25* to 107*. their was no chipping or busted off teeth on any of the gears, so that part of the inspection eliminated that. i will try the paint test and see what I come up with. I did pull the old pilot bearing out tonight and it had some slight wear on the bottom. I will keep at it until a solution comes up!!