As I understand, this is the reason for 5th gear grind on some Evos: due to the large gap between 4th and 5th, the latter being very tall, the synchro wears abnormally if one tried to shift quickly. In essence, the synchro doesn't have a chance to catch up and becomes damaged over time. The solution is not to shift fast from 4th to 5th.

I only have ~50K on my IX, albeit quite a bit of it at WOT, so I'm not sure it's a real data point. Never a grind. Not once. Always OEM fluids - no exceptions. I don't shift terribly fast; just quick enough not to loose spool.

 

Okay, so there's more damage?

 

The ratio gap + it's only a single synchro is what kills. If Mitsubishi had made it a double synchro, it probably would've been a lot better.

 

Fork break = metal pieces everywhere = chipped gears = ruined trans.

 

WTF !! how did it happen ?

Was there any oil in the trans ?

 

Gotcha. I didn't think about that. Lol

 

Missing alignment dowel pin caused an off-center clutch disc, resulting in crazy vibration, ending in a fork vibrating itself to death.

 

Do you think vibration can cause the fork to brake ?

If fork was vibrating you can feel it during drive and shifts or may be you were more focused on apexes and corners

 

 

Reporting back with a small update. Still no issues at all with 5th gear with the Red-Line fluid in the transmission.

Looks like this will get changes with only MT90

 

I use MT-85, but with what you said maybe Ill give the 90 a try and itll help with my notchiness

 

Ever tried the Royal purple gear oil ?

 

Not gear oil specifically, but I've used their other products. Too over-priced, and for my particular application, I didn't get good results.

My GSX developed rod bearing knock right after switching to that oil, after the car had ran beautifully for years. Could have been completely coincidental, but I do not like how it suddenly started after switching to it from years of using Mobil1/Ams Oil.

 

I use Royal purple engine oil 10w40 - works good . Used it in 42C ambient temps, hot humid weather . Never had a problem.

Did not find Red line here so was thinking to switch to royal purple gear oil.