Gearbox Synchro?

[fras]

What cause them to go bad and what signs?

[bushwakka]

well boy, i watching this topic too yea, i wanna kno de ansa...but i tinkin de signs are that grinding sound when u tryin to engage gears normally

[OldSkoolRule]

tryin to shift w/o clutch (timing the gears), extremely fierce-clutching during shifts, low-oil; this one de biggest culprit and is a tief head, because you only know the gearbox is dry after you hear the grinding noises and damage has already started . symptoms- A Grinding noise during normal shifting just before the gear slips into position. In extreme cases, the gear would also jump out of position under torque or heavy load. Keep checking your gearbox-oil; Redlinde Synthetic Shockproof is highly recommended, unless you won't put $500 in gearbox oil in your box, then Bel-Ray is just fine; and you guys shouldn't have any synchro problems........oh, AND leave the clutchless shifting to me (cause i could fix it after ah done mash it up)

[MISHI]

Also it should be noted...

Most gear oils come with a API spec of GL-4. Most times people put in GL-5 gear oil in their gearboxes. This eats the syncros for breakfast.

Whatever oil you use, make sure it's a GL-4

Mitsubishi recommends a 75-85W or 75 -90W Oil in GL-4

I never realised that issue. All the years I used GL-5 oils and have gear issues.

There was one instance my mechanic used Bel ray oil... a GL-4 I believe... it was the best the box ever worked. Maybe you can give it a try.

[fras]

Thanks for the info OldSkoolRule.


Word MISHI

[reiXmann]

[fras]

Scene

[bushwakka]

i find the synchros rel fawk up...cya shift too fas or downshift witout blipping the throttle correctly

[SNIPER 3000]

Yep Bel ray oil GL-4, is good enough .

[Knight1]

[bushwakka]

wuts ur name on scooby knight? yea...well i realise that u can't do the fast shifting wit de synchrobox by now, i jus sayin dat i prefer de ole gearbox an dem.....can anybody tell me if dem frontier dem hav synchros on it too?

cuz i shift those gears pretty fas an no grinding whatsoever

[Knight1]

^^Almost ALL street 'boxes use synchros.

From Type R Hondas to Porsches. You CAN shift quickly, but you have to take the time to learn the technique to do so with YOUR car. I wasn't able to do that with my Suby early on...but now I can nail pretty quick shifts 2-3-4 without a jerk. 1-2 is always a tough one (as there's as much as a 30% rpm difference...so synchro "working" time is a bit longer), so I take my time with that. 4-5 is always easy, as there's prob. only a 10% rpm difference.

In short, take the time to learn your car, and how the gears engage.

In the case of the Frontier, the gears/flywheel/drivetrain etc may have more rotational inertia, meaning that shifts are easier between gears (a bit hard to explain by just typing).

[bushwakka]

ok....shifting fast from 2nd to 3rd on my car is the only problem, the other gears i can shift between as fast as i want

so what possible technique can be employed when shifting from 2nd to 3rd? is it to do with clutch positioning or blipping the throttle or what?

[Knight1]

Neither.

It should be a normal shift. No blipping throttle during the shift, unless you're doing Heel&Toe downshifts (3 to 2). Don't blip during upshifts (bad for synchros).

Have someone else (say more experienced with manual, or a mechanic) drive the car. Someone who isn't accustomed to it....and get their take on it.

If the problem still persists, time to carry back to the firm.

Have you tried double clutching to see if the problem goes away?

Double clutch =

In 2nd -> put down clutch -> move to neutral -> release clutch pedal

then

In Neutral -> put down clutch -> move to third -> release clutch pedal


You're essentially engaging your clutch twice between that 2nd - 3rd shift.


If THAT solves the problem....., and the mechanic/experienced driver ALSO had the same grinding issue that you did, then.....

....your synchros may be busted (no offense...but do you think your driving caused it? Very aggressive?)

[bushwakka]

well as i said, i only get the problem when shifting from 2nd to 3rd slightly fast...when i first bought the car, i had to shift between 2nd to 3rd progressively slower to avoid that grinding synchro noise

admittedly, i tried shifting fast a few times when i bought the car, but not all that much...

jus out of curiosity....how big a deal is it to have a busted synchro? big problem? expensive?

[blackNshine]

fras,try an oil change or even adjusting the clutch and see if it makes a difference

[Knight1]

[fras]