Gear grinding....anyone know?

[91MRtizzle]

My car grinds when i shift into 3rd at 3k plus rpm and also when i downshift to second. Is there anyway to get rid of it without gettin a new tranny? my friend says changin the tranny fluid but how do i go about doing so?

[MRQtwinturbo]

changing to redline tranny fluid or GM syncromesh may help...but if syncros are already damaged u will have to replace them...

[5Sfte]

Sounds like synchros to me.

[91MRtizzle]

Thanks. I will try to change the fluid soon. How much do synchros cost to replace? if i do replace em?

[Ratko]

The synchros themselves as relatively cheap... its the labor of pulling the tranny, and taking it apart that is pretty expensive.

[HUGEZMR2]

Hi Guys,

I am 99.9% sure it is your clutch slave cylinder that is the problem. When the flywheel is revving high, more pressure is required to move the pressure plate on the clutch. My MK1 MR2 does that when I'm booting it around. The clutch slave is not releasing the pressure plate all the way.

Check your clutch fluid, check your clutch pedal for any leaks etc. If you see any fluid leaking around the pedal, clutch slave needs to be replaced for sure.

But the problem you're having is most likely that, and not the synchros. If the synchros where out, your gears would be grinding all the time.

HugezMR2

[toyotaspeed90]

taking a FWD tranny apart (yes, i know it's RWD... i DO have an mr2... but it's still basically a fwd transmission setup) is pretty difficult.... people debate even getting an LSD because they feel it isn't worth the labor....

[zyg0te]

i have the same problem on my celica, i dont know what the problem is... but if i double clutch at high RPMs (redline) it shifts smooth.

[MitchB]

Synchromesh is a FAR superior solution to Redline MT-90. You don't, however, know for sure if it will provide adequate protection for long life of the gears themselves, but that is based on many, many, many thousands of miles of driving. It will do an amazing job of "repairing" synchros though.

I HIGHLY suggest that you fully drain and refill your tranny with Synchromesh before you take anything apart. Also, Pennzoil and I think Texaco offer the same products (made to the GM spec) for less money. GM gets $9.91US / liter, while Autozone charges $4.99US / quart.

Worn synchros are not necessarily in need of replacement, just use a "better" oil.

And don't forget to bleed that clutch slave like was suggested earlier.

[Ostornadoe]

Thread revival time.

What exactly are synchros, and would it be possible that the synchros are worn if my car only grinds in 2nd gear?

I searched, and this thread was the best that I could find. My car grinds going into and out of 2nd gear most of the time.... It also feels like I've lost a little power, not positive though, would worn synchros be the cause of this loss or is it something else?
Any info is appreciated.

[MitchB]

A synchronizer is a "friction" unit driven by the shift fork in the tranny. When you shift, the synchro parts come together and bring the speeds of the different gear shafts close enough together in speed so they can mesh without "grinding".

When the synchros deteriorate by "normal" wear, the oil that is between them squeezes out too quickly during shifting and the gear parts come together before the speeds are matched.

GM Synchromesh was designed to fix this problem in the Quad 4 drivetrains (IIRC). Like I said before, Pennzoil and others make this same spec fluid.

Any loss of power is not from synchros, since they only work during shifting. As long as the tranny is solidly in gear, the synchros job is done.

[arcasmachineracing]

Yup, Syncromesh all the way baby!

Put it in my two, made a world of differance, eliminated the 3rd to 2nd grinding issue and over all made it feel much smoother! I was very impressed. Let it stay in the transmission for about a week before you pass judgement on it, it seems to take a while before it really 'works?' I dunno why, but it does work great!

Highly Reccomended!

ps. don't spill any old transmission fluid on your car/ground/self, that shit stinks like baby poop!