So, very suddenly, my 2007 Mazda 3 with a manual five speed would intermittently not go into first or second. It would either work perfectly or not go into gear at all. Adjustment had no effect, and it would work great for several hours or even days, then lock out 1-2 (not even gate into the 1-2 part of the "H"). So I took it out and took it apart. Inside I found one tooth(the ones the syncros mate with) broken off of the 3-4 shift ring and the syncros looked fine (although the pair for 3-4 would bind if you put any pressure on them and tried to turn them.
I opted to get a used trans rather than rebuild the original and now I am paying for that. The new/used trans shifts through every gear great. BUT. It will NOT go into reverse. (I did run it through the gears on the pallet, before install, and it seemed fine) It goes down the gate path for reverse, and if you let the clutch out you can hear it "touching" as it is barely starting engagement but no combination of 1st, 2nd, clutch, prayer, or profanity, will make it go into reverse. I double checked to make sure there was nothing touching the shift linkage, and I checked the reverse switch, to make sure I had put the copper washer in so it was not having a clearance issue.
There is the feeling that something is keeping the gears from engaging as the shifter stops and you cannot even lean on it to get a good gear grind, you can just barely hear the gears contact, but there is nothing I can see and the trans has not been apart.
Any ideas before I dig back in? The used trans has a warranty but I am tempted to take it apart and combine it with the original one to make a decent new one rather than return it for another used one.
Have you had the center console off and had a look at the shifter?
In reply to BrokenYugo:
That was the first thing I did when I had the initial problem with the 1-2 shift. I was hoping something was trapped in the console and catching the shifter. Unfortunately, that was not the problem. I even took the shifter box apart and checked for a broken piece.
With this second trans, I tried shifting it into reverse at the transmission and it is hanging up. The 3 has a reputation for doing this, no reverse syncro(Which is something most cars don't have?) and where the gears mesh is very flat with little bevel. I am going to run the car around and see if this is just an intermittent issue. I don't mind taking the transmission apart, taking it back out of the car is the part that is a pain.
RossD
UltimaDork
3/8/17 7:36 a.m.
How are the motor/transaxle mounts? Has the car been in an accident?
Any trans with a finicky sliding gear reverse that I've run into you just kept pressure on the stick while very slowly letting off the clutch until the clutch slipped enough to pop things into alignment, or let the clutch up and then clutch in and quickly grind it into R with the input shaft still spinning. I wonder if you might have a bent shift fork in there or something.
In reply to RossD:
No accidents. Two of the three mounts are newish, the third one is solid as new. Plus it will not shift, to reverse, even when actioning from the linkage on the transmission
In reply to BrokenYugo:
It might be a bent fork. All of the usual tricks for a finicky reverse are not working. The original trans required a little second/clutch, then quick shift to reverse. This trans it feels like it is not even trying to mesh gears.
That would make sense if these are known to be hard to get into reverse, PO lacked mechanical sympathy and banged on the shifter, gradually bending stuff until it quit engaging. I'd just warranty it.
Removed transmission, took transmission apart (all the way apart), checked everything, found a tiny rub mark on the interior of the fifth gear cover where is was dented. I did not remove this cover(which can be easily removed while the trans is in the car) while trying to figure out what the problem was, because I knew there was only the fifth gear set and the shift fork for fifth. Turns out the shift rod for fifth moves when you shift into reverse and it gets REAL CLOSE to the cover. So close that a 3mm dent will keep reverse from engaging. So, after about 4-5 hours of removing the trans, tearing it down, and reassembling it, I found I could have fixed the problem in a half hour by removing the driverside wheel and a small plastic access cover.
The most frustrating thing is that I almost replaced the dented cover with the one from the original trans but figured why take the extra step.
