CChris17rx8

First gear, seven thousand rpms and above, shift into second, and grind, grind, grind!!!!!!!!!!!!! Are my synchronisers bad?? at least 2nd gear? Who sells them ????

Jethro Tull

iTrader: (6)

Is it all the time, or only on a cold tranny?

What's your mileage, how aggressive do you drive, how old is your clutch?

CChris17rx8

It happens after driving 30 mins. (or more). 66Kmi. on the car and clutch I think (purchaced it used at 49Kmi.) I changed the trans oil last year when I first noticed it. It was clean, and new oil made no change. It also "bites" into 2nd (only) when driving slow, like through a parking lot, it I shift too quick. IDK, but if it was a clutch problem, I think it would do it in all gears. I do have a noisy throw out bearing, but I feel it is a synchronizer.

Jethro Tull

iTrader: (6)

The clutch bracket may be bad. It is known to fail. Check that first, before you suspect synchros or clutch.

CChris17rx8

Are you talking about the clutch pedal bracket?

Jethro Tull

iTrader: (6)

Oops! Yep, I left out that key word. That's the one I was referring to.

RX8.PIPE.DREAMS

iTrader: (1)

What kind of tranny fluid are you using? I have a grinding issue with 5th gear that lessened alot after swapping some MT90 in there. What year is your car? If you have an 04, the aisin unit does not like to be rushed. I have found that a slight delay in shifting can inhibit the grinding. Try that. Since you're obviously out of warranty its your best interest to look and experiment with some fluids before going after the expensive work (ie. transmission rebuild.).

CChris17rx8

The clutch pedal bracket looks ok, I have seen a broken one in another car, and there are no signs of stress on mine where the other one broke. My 8 is an '04, and has an aftermarket warranty which expires in August. Shifting slow helps, but 2nd gear just always feels different than the rest. I wonder if I should find a 6spd from a salvage yard out of a newer car, or see if Mazda offers upgraded parts. Thank you for the info about the '04. By the way, I tried 75W-140 Motorcraft Synthetic, but it was hard to shift in all gears when cold. Lucas 80W-90 is what is in it now.

TeamRX8

iTrader: (25)

Regular gear oil has limited slip fluid in it, which doesn't work well with synchros

use Redline MT-90, 75W90NS, or 75W140NS

*the NS designation indicates no limited slip fluid is used

ManicMechanic

I think a late model 6spd is the best option. Modifier is ment for clutches (ones in a diff.) it won't help or hinder a gearbox without any. Good luck. This is the best time to replace your noisy throw out bearing, but I'm sure u knew that!

ManicMechanic

Check out the "troubleshooter" section, goto "tranny issues" many others haveyour problem!

kersh4w

iTrader: (3)

i used mt90 and my 10k mile old transmission started having a 3-4 grind. that was 3k miles ago and i havent really driven it hard since. scared too find out what will break next.

:/

i think i'll go to 75w90NS.

i replaced the trans once. im not replacing it again. at least not with another POS transmission.