Dear Mechanically Inclined Ecomodders:
 

Hello everyone. I am not completely lost when it comes to car repairs, but I am not what one would call "experienced." The extent of my vehicle repair career has been a water pump replacement, an alternator replacement, and routine oil changes. Therefore I don't really know what's wrong with my car. I will try to keep this as brief as possible.

My car was previously owned by a college girl who didn't know how to drive a manual transmission, and since I bought it the transmission grinds when I put it in reverse. Sometimes it takes a couple attempts to get it to really "lock in" and occasionally I have to let the clutch out part way while yanking on the shifter to get it in reverse.
Also since I bought it, it grinds when downshifting into second gear at any speed over about 15 MPH, but only when the transmission is warm.

Lately it's begun to grind when upshifting into fourth and sometimes into fifth, and more alarming still, my car would not let me downshift into fourth last night on the freeway. I was going uphill at ~50 MPH, and could not get it in gear. In a panic, I went for 3rd which worked just fine.

What is the problem here? I thought the grinding second gear could just be that it was previously abused (Maybe a worn gear or a syncro issue), but this sounds like a clutch issue; like it's not fully engaging. My car has 42k miles on it, I have only ever driven manuals, and I am very gentle with it. The clutch is firm otherwise.

Any ideas? Thank you in advance.

~Matt

It very well might be the clutch going out. My Sebring had exhibited much the same behavior for shifting into reverse, at the time it got totalled.

I know on my Sebring, the clutch fork was made of this really soft iron, which was slowly eroding against the pilot bearing. It appeared to be a well-known failing of its transmission, and it caused the shifting to feel like to clutch was going out. The fix was to either purchase an upgraded hardened clutch fork from one of the speed shops specializing in Chryslers, or install a hardened pad on the existing clutch fork.

...to me, it sounds like "she" ate up the synchronizer clutchs between gears.

I think this tells me that the clutch is not the problem. A clutch problem that causes shifting issues is usually a clutch not releasing fully. The fact that you have to [once in a while] let the clutch out a bit to get it into reverse tells me that the clutch is releasing fully. This is a normal thing for reverse, as there is no syncro to line the non-spinning gear up to engage. All of the manuals I have owned did this in reverse.

A way to test the clutch for slipping is to simply gear down so the engine is at peak torque rpm (~4000 or so), floor it, and hold your speed steady with the brakes. I call this the "left foot dyno" at work, where I do it all the time with commercial trucks for engine diagnostics. Obviously just do it long enough to see if the engine rpm increases (clutch slipping) while the vehicle speed remains constant.

Your grindy shifting tells me that you have syncro issues. If you are brave you can attempt to replace them yourself. Sounds like you know that basics around a car. With a decent manual and some courage, it's not that hard. Just nuts and bolts.

Your best "hope" is the clutch is not completely disengaging. The only mnaul Toyota's I have owned, of recent manufacture, do not have adjustments for the "free play" in the clutch, in particular a 2001 Echo, which is very similar to the Yaris.

Make sure you are fully depressing the clutch pedal and see if that makes any difference.

Is the clutch engagement point close to the floor of your car? If so you may not be getting complete disengagement. When going into reverse see if putting it in 3rd gear first helps to stop the grinding. Also you might try bleeding the clutch to make sure it has no air in the hydraulic system that would prevent complete disengagement.

If the clutch disc is warped you may not be able to get complete disengagement.

If none of these works then I would agree with the previous posters who think the synchros are shot from the abuse by the previous owner. Considering the fairly low mileage, it might be better to replace the transmission with a used one if none of the clutch disengagement precedures give you any positive results.

regards
Mech

If the transmission refuses to shift in to another gear, the transmission is telling you it is unable to match gear speeds. The device that is responsible is something called a baulk ring (also called a syncro).... If the baulk ring is damaged there are 2 things that could happen... Either it refuses to shift between gears no matter what you try or you may notice you can shift in that gear but it briefly grinds...

To prevent the grinding you have to SLOWLY engage that gear to give a damaged syncro a chance to match gear speeds. If it refuses to shift you can try double clutching. You can youtube how but the skinny is you are in gear ready to change...you clutch in, shift to neutral, clutch out, clutch in, shift to new gear....what this does is slow down the gears to make it easier to engage the next gear.

The only other possibility I can think of is the incorrect type of transmission fluid was put in the transmission which can cause major issues. The "cheap" thing to try would be to change out the gear oil and (if applicable) adjust the clutch.

I also suspect the master cylinder for the clutch. I had one fail recently making my worn syncros feel worse. Instead of true double clutching, try double pumping the clutch just before shifting. This was able to build enough pressure to shift on mine before I replaced my master. Mind you this is just a test. If it is that bad, that you need to pump up hydro pressure to shift it is time to replace.

Thank you everyone for the responses, I really appreciate it; definitely gives me an idea of what's going on.

When I bought the car, the dealer gave me a run-down of the previous owners. The first owner put 24k on the car and had it regularly serviced, the college girl owned it for 4k miles, and then when she traded it in the dealer had it serviced early. I hadn't even considered that they would put the wrong transmission fluid in, I guess that's my fault. It's been on the back-burner to replace the trans fluid with synthetic, I guess I'll have to move it to the front and hope that the ~12k I've put on it hasn't damaged anything too irreparably.

I have tried rev-matching when shifting with little positive effect, which makes me think it might be the syncros. The crappy thing is I don't really have a shop space of my own, meaning I might have to take it in to get it fixed.
Good thing I just got my tax return.

I'll try bleeding the clutch when I replace the trans fluid and we'll see what happens.

I would change the transmission fluid using OEM style fluid, if that is synthetic then use that, but if it's not then I wouldn't use synthetic, reason being is the synthetic can be slipperier due to friction modifiers and the syncro problem is that they don't have enough grip in their little wet clutch plates.
I think your owners manual suggests new transmission fluid every 90,000 miles under normal/light use but it sounds like your car had harsh use for a bit so it's time already for new transmission fluid.

The trans is toast. Not the clutch the shift forks and syncros are gone. Find a replacement.