2nd gear Grinding Manual Transmission

New fluid... sure give the Redline a try but new fluid doesn't rebuild a transmission. 30k isn't ONLY has. Most of my manuals have had 4 drain/refills by 140k miles.

Bleed/adjust clutch/shifter and everything. Could be simple as bushings somewhere too.

I had a hard to shift transmission, tried everything, and gave up. Few weeks later, the motor mount started knocking around. Replaced all the mounts and the transmission shifting became perfect. Another was a nightmare until I replaced the clutch.

 
My wife went through this on her saturn. It's always second gear. Teach her to double clutch this car, it will save the synchros on every subsequent stick shift you ever buy. In other words, hold off for a little bit on fixing this. Finally if you do manage to fix this with a fluid change, it's a miracle, and should be double-clutched from here on out anyway.

I wound up getting a junker car, swapping transmissions back and forth, then selling ole' grindy with full disclosure for more than I had into it, lol.
 
2nd gear is the synchro that almost always becomes worn first because folks most often downshift from 3rd or 4th into 2nd 'round a city-speed corner. Most folks out there don't double-clutch to downshift. 130,000 miles will do it, easily... That's not a young transmission (if downshifts haven't been double-clutched from day 1).

Also, air in the clutch hydraulics (resulting in NOT a full disengagement of the clutch) aggravates synchro action... and the lowest gears have the hardest job of synchronizing. First gear would typically be worst, but it is 2nd gear in most cars that gets used the most... so inadequate clutch disengagement due to the air in the hydraulics "presents" as a second gear prb...
 
The idea of bad/water saturated clutch system fluid is a good one-I have late/pedal to the floor clutch release on the Corolla. With the external slave cylinder, bleeding it should be easy enough with a Mity-Vac-I’ll have to try it. Hasn’t affected forward gear shifting, though, only reverse.
 
I had a '93 Corolla with that issue. Tried multiple fluids some of those listed above. Friend that was a BMW said they were using BG SynchroShift II in the BMW's with the same complaint. I think it was a TSB for them.

3 qts and 20 miles later all my grinding was gone. That was after multiple shops said I need rebuild since teh other fluid changes didn't work. No grinding for over 100k more until car got totaled. I changed the fluid yearly after that, it was cheap insurance. 220k on the Corolla it still shifted better than the Sonata that replaced it from day 1.
 
Another issue on worn engines is excessive crank end-play due to worn thrust bearing flanges. It can move away 15 thou, and if you are only gaping the pressure plate 30 thou you will have clashing. Sometimes this shows up with used, thinned motor oil.

I have constantly had issue with hydraulic slaves and adjustment on Asian vehicles and Chevy and Ford trucks. Conversely, in the past, I was always able to deal with mechanical linkages and their proper adjustment.

- Ken
 
Sounds like worn or damaged second gear synchro.

I had a 1986 Jetta with leaky axle seals, lost enough gear oil that the 3rd gear synchro went out. Then I learned to double-clutch 3rd.
 
My Maxima hose (there were more than 1 section unbeknownst to me at the time so I got wrong parts) developed a leak and air got in, and it took a long time to notice the level drop....
 
If double clutching resolves the grind, then that means the synchronizer is gone.

I highly doubt any oil will help, you will need to double clutch the second gear all the time, or rev it out in 1st and go to 3rd. It’s either that or fix the tranny or get a used one, which may have the very same issue anyways.

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I would check the engine/transmission mounts. When they are worn and allow excessive movement, it can affect gear shifts.
 
I took a bit of air out of the system by bleeding it. I will change the trans oil later this week. I still need to double clutch on second. Based on the behavior of all other gears, I think the second gear synchro is a goner.
 
Contaminated old brake fluid will reduce the distance the clutch disk moves away from the flywheel when you step on the clutch, causing it not to fully disengage, especially after driving a while when things get hot. It can happen occasionally, but when the fluid is real bad it can happen all the time. Driving it that way will eventually cause excess clutch wear and can damage the transmission. It is cheap enough and easy enough to try and if the synchros are good, and the clutch is good it more than likely solve the problem.
No disrespect, but do you have any factual evidence for this? How does fluid "degrade?" One of the primary rules of fluids is that they are incompressible. Degraded water or contaminated or old, whatever, will not compress any more or any less. I don't see how old contaminated brake fluid would compress any different than new. Water intrusion leads to corrosion problems, not compression issues.
 
No disrespect, but do you have any factual evidence for this? How does fluid "degrade?" One of the primary rules of fluids is that they are incompressible. Degraded water or contaminated or old, whatever, will not compress any more or any less. I don't see how old contaminated brake fluid would compress any different than new. Water intrusion leads to corrosion problems, not compression issues.
The fluid is hygroscopic and as a result it degrades from taking on moisture, and the boiling point of the brake fluid becomes lower. If it didn't there would be no reason to swap out brake fluid every few years as maintenance to a braking system. Simply bleeding the clutch has resolved many cases of clutch related issues due to the clutch not fully disengaging. Plenty of info on the web, and numerous discussions over the years here on Bitog.
 
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Just put some redline mt90 in it with a small amount of Lucas. The wife and I both drove it around for about ten minutes and couldn't get second to grind even when single clutching. I'm definitely still going to double clutch when down shifting. Again thanks to everyone here for sharing your insights. I just saved a bunch of money. I'm probably going to take over the primary driver duties of this car. Maybe about 30k per manual transaxle oil changes moving forward??
 
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My 11 Mazda 6 does this. I’ve been double clutching for at least 50k miles by this point. I don’t want to put a new transmission in it. The car is approaching 190K miles at this point and I’m fine with it as is.
 
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