2nd gear synchro woes

mTk · Post by **mTk** » Wed Mar 24, 2004 11:33 pm

Just as the topic sounds, my 2nd gear synchro is on it's way out. Grinds when i upshift, grinds when i downshift, if i get it at jsut the right RPMs it's OK.

There are a few thing i am going to try before i do a rebuild or replace. I'll post them in this thread, as the sticky is muddled with other stuff.

MK

evolutionmovement · Post by **evolutionmovement** » Thu Mar 25, 2004 12:51 am

Sounds like a reason to learn double declutching and heel and toe

Steve

mTk · Post by **mTk** » Thu Mar 25, 2004 1:43 am

1st attempt: Switched to 40w Castrol GTX (yes i know it's much lower visc than the recommended 75w90)

So far, excellent, the grinding is nearly gone under all condtitions.

MK

mTk · Post by **mTk** » Wed Apr 28, 2004 7:34 am

Went ahead and tried 75w90 Royal purple gear oil today.

Problem is worse, 2nd gear synchro will grind under high rpm shifts.

Time to switch back to 40w

MK

NICO · Post by **NICO** » Wed Apr 28, 2004 10:48 am

mtk you got the right idea, i no what is going on, the trannys are very very pickie about what oil gos in. they are really really strong, but if you put the WRONG OIL in then they will blow up, or grind, or not even go in. i whent threw five trannys just to figger this out how to stop it, i like the factory stuff and i have to change it 3 times a year no more busted gears for me.
keep testing mtk you will find the right oil for it.

vrg3 · Post by **vrg3** » Wed Apr 28, 2004 4:02 pm

I think I said this in another thread, but 40W motor oil is similar in viscosity to 75W90 gear oil.

Have you tried using Castrol gear oil?

georryan · Post by **georryan** » Wed Apr 28, 2004 5:29 pm

So Castrol 40w would be similar to a castrol 75w90 gear oil?

Post by **DLC** » Wed Apr 28, 2004 5:32 pm

Gear and motor oil weights are measured differently, for some reason, so i think vrg3 is onto something. It might be some property of the motor oil that makes the synchros less picky.

vrg3 · Post by **vrg3** » Wed Apr 28, 2004 5:45 pm

Yeah... I found the other thread:

http://bbs.legacycentral.org/viewtopic. ... 5938#55208

mTk · Post by **mTk** » Wed Apr 28, 2004 6:07 pm

http://www.irvingoilco.com/images/viscosity.gif

posted for the lazy.

*hopefully* this weekend i can change it again, i'm going to try to find synthetic 40w or 30w motor oil.

MK

vrg3 · Post by **vrg3** » Wed Apr 28, 2004 6:12 pm

You're pretty determined not to use gear oil? I'm a little worried about your front differential.

heelhooker · Post by **heelhooker** » Fri May 14, 2004 11:09 am

redline mtl 70w-80 is working quite well for me. I was getting grinding going into 2nd gear before switching oils.

Paisan · Post by **Paisan** » Tue May 18, 2004 1:26 am

Excellent thread. I have 2nd gear grinding in my '94 Legacy as well. I switched to Amsoil 75-90, going to try Redline now and see if that helps, last resort will be the subaru stuff.

-mike

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2nd gear synchro woes

2nd gear synchro woes