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-   -   Anyone ever "fix" a scratchy synchro with fluids? (https://www.miataturbo.net/general-miata-chat-9/anyone-ever-fix-scratchy-synchro-fluids-69571/)

hustler 11-20-2012 10:42 PM

Anyone ever "fix" a scratchy synchro with fluids?
 
I have a 6-speed running MTG but it's a huge POS crunch-box. 3rd gear does not like to downshift. Can I add some GM friction mod or AMSoil slip lock and get any improvement?

y8s 11-21-2012 09:43 AM

Synchros need friction to function properly. Adding friction modifiers (ie slipperiness) will make them worse.

hustler 11-21-2012 10:49 AM


Originally Posted by y8s (Post 951879)
Synchros need friction to function properly. Adding friction modifiers (ie slipperiness) will make them worse.

I never knew what FMs did, never researched it. I thought they made things more slickery. I guess I can over-fill and see what that does.

Never, ever buy a transmission from an auto-x'er, even if he says he only drove it a couple times.

18psi 11-21-2012 11:07 AM

wait didn't you yell at a n00b for suggesting the same thing?

LOLOL

oh the ironing

hustler 11-21-2012 11:11 AM


Originally Posted by 18psi (Post 951909)
wait didn't you yell at a n00b for suggesting the same thing?

LOLOL

oh the ironing

Never. Again, I don't understand how the slip-lock works so I'm not going to troll anyone over it.

NiklasFalk 11-21-2012 01:32 PM


Originally Posted by hustler (Post 951910)
I don't understand how the slip-lock works so I'm not going to troll anyone over it.

Friction is used to accelerate/decelerate the input shaft to make the next gear slide in smoothly. Blipping during downshifts makes this process faster.

At least that's my understanding and I'm content with that level of detail (ignorance is bliss :)).

Fireindc 11-21-2012 01:34 PM

What fluid are you running in the trans?

hustler 11-21-2012 02:00 PM


Originally Posted by NiklasFalk (Post 951965)
Friction is used to accelerate/decelerate the input shaft to make the next gear slide in smoothly. Blipping during downshifts makes this process faster.

At least that's my understanding and I'm content with that level of detail (ignorance is bliss :)).

Oh goody, answers to questions I didn't ask. Tell me more.

hustler 11-21-2012 02:01 PM


Originally Posted by Fireindc (Post 951968)
What fluid are you running in the trans?

Half AMSoil MTG, half pterodactyl ejaculate.

y8s 11-21-2012 02:05 PM

friction modifier is used to reduce friction between parts.

synchros NEED FRICTION to work.

gohead and add it and complain more?

hustler 11-21-2012 02:08 PM


Originally Posted by y8s (Post 951986)
friction modifier is used to reduce friction between parts.

synchros NEED FRICTION to work.

gohead and add it and complain more?

I was on board with slip-lock reducing friction from post #2 of this thread.

Fireindc 11-21-2012 02:50 PM

this stuff? AMSOIL - Synthetic Manual Transmission and Transaxle Gear Lube 75W-90 (MTG)

Seems like it would work well, although I'm using this ford motorcraft fluid and noticed a huge difference from whatever the fck was in there previously.

Motorcraft MTX-75 IB5 transmission fluid XT-M5-QS

Although since that Amsoil stuff is GL4 fluid it should be good from what i've read. I LOVE amsoil and it's all i run in my Buell.

chicksdigmiatas 11-21-2012 05:01 PM

The Motorcrap posted above was a step up from my redline, it noticeably improved shifting.
If not, I have a synchro or two if yours are out of spec I could mail you.

mx5-kiwi 11-21-2012 06:22 PM

This thread is perfect timing. my new to me, sat on a garage floor for a year or two 80,000 km 6 speed shifting was/is horrendous as well.

I might try the motorcraft if we can get it here BUT have noticed in the past week as i use the car more, the gearbox is improving. Perhaps sitting around wasn't the greatest and using it is wearing any rust or whatever off.....

I race national MX here in NZ, the Motul "Pro" gearbox oil is shithouse. Jumps out of gear, won't go in to gear etc....(life threatening on a MX track!)"Downgrade" to the bog standard Motul transmission oil (1/2 price) and shifts are perfect.

I came to the conclusion the "Pro" shit was too slippery and the synchros etc were not coping....told my friends who were haivng the same problem and they all ended up with the same conclusion.

Who knew, oil can be too slippery....!

miata2fast 11-21-2012 08:27 PM

You may find your self diving into the art of tranny rebuilds. Put on your happy face. ;)

hustler 11-21-2012 09:05 PM

STFU about the Motorcraft shit gear lube. This is not that thread, go away.

hustler 11-21-2012 09:07 PM


Originally Posted by mx5-kiwi (Post 952104)
This thread is perfect timing. my new to me, sat on a garage floor for a year or two 80,000 km 6 speed shifting was/is horrendous as well.

I might try the motorcraft if we can get it here BUT have noticed in the past week as i use the car more, the gearbox is improving. Perhaps sitting around wasn't the greatest and using it is wearing any rust or whatever off.....

I race national MX here in NZ, the Motul "Pro" gearbox oil is shithouse. Jumps out of gear, won't go in to gear etc....(life threatening on a MX track!)"Downgrade" to the bog standard Motul transmission oil (1/2 price) and shifts are perfect.

I came to the conclusion the "Pro" shit was too slippery and the synchros etc were not coping....told my friends who were haivng the same problem and they all ended up with the same conclusion.

Who knew, oil can be too slippery....!

You have a GL5 lube in when a GL4 is required, no wonder it shifts like shit. the AMSoil MTG is for extreme use, Motorcraft and Synchromesh for dialy driving.

hustler 11-21-2012 09:07 PM


Originally Posted by chicksdigmiatas (Post 952078)
The Motorcrap posted above was a step up from my redline, it noticeably improved shifting.
If not, I have a synchro or two if yours are out of spec I could mail you.

Thanks but I'll just dump this trans and get another...from my garage.

hustler 11-21-2012 09:08 PM

I just changed the shift boot from the old vinyl one to a leather boot. Do you think that will increase my homosexual lust?

Saml01 11-21-2012 09:33 PM

I have been running Royal purple for the last 14k miles, id say its pretty good. Then again my shit only has 34k miles.


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