I have been going through this for quite some time and I am about to take a sledgehammer to my tranny. From previous posts I have mentioned the fact that my truck seems to have started acting up since replacing the clutch mechanicals. I even went so far as to mention the rear end, but now I beg the differ. Here is what I am noticing. As I am sitting in my truck shifting the gears (truck NOT on) trying to get a feel if the shifting is correct, I am leaning on the fact that my fourth gear is not in sinct. I don't think that the shifter is going all the way down as second and reverse. This could be why the truck is again seeming like it is in two gears at the same time, i.e. not going in gear or locking down, especially in reverse. All the other gears seem to be fine except fourth. Therefore when the engine is running, the truck seem to be in gear already when actually I only have it in one gear. If I put it in first to take off, It will not disengage to go to second. I have to put it in neutral (basically force it out of gear) and place it in third. By then the speed has slowed and the truck nearly stalls, so I rev it to match the rpm. Does this sound familiar to anyone, and if so, what needs to be done. I have removed the shifter, and don't see anything in there from any mangled bushings, but something has got to be in there. I am out of ideas.

 

Can I remove the cover as mentioned in a previoius thread and take a looky see. I am hoping to be able to see if anything had droped in there, without taking the tranny all the way out and opening it up.

 

You can pull the top off if you wish. It's a little tricky to get back on sometimes, you have to engage 3 forks into the sliders. At least that's how it was on my 4 speed. If you can put the truck in neutral and let out the clutch without the truck stalling then it's not stuck in 4th. I had a problem with my 4 speed not wanting to go into gear, it seemed like it was stuck in gear and when I put it in 1st it would lock up. I never figured out why, that was when I had to drive it 15 miles home in 2nd and swapped in the 5 speed after that.

 

That is the way mine is acting. I can put it in neutral and let off the clutch and it is fine. That is usually how I start the truck, but when put in gear, i.e. the engine is on it acts as though it is already in gear. The problem mentioned above is when there is no engine running and I am sitting in the driveway. All the other gears seem as though they "go in". The fourth gear doesn't seem to follow all the way through. Again, this is without the engine running. This tells me that something is hindering it, which has a ripple effect on the 1/2 gears, because I can't get out of them. I know I didn't drop anything in there. I am just out of ideas, and I don't have the funds to rebuild.

 

Is this the Mazda 5 speed like I have? I'm leaving work now, I'll have a look at the manual and get back to you tomorrow..thinking syncro.

 

I remember a similiar problem the first time I rebuilt my 4 speed, and it may be the problem with yours and probably was the problem with mine before I swapped it out. When my92 said syncros it rang a bell. The syncros are weird things with gears, springs, metal tabs and notches that the tabs slip into to syncronize. Upon reassembly of my tranny, the shift ring slipped on me and the little metal tabs popped slightly out of place. This wouldn't allow the ring to shift into one gear. Each ring shifts 2 gears just like the forks. Since the tabs were out of place on one side that gear wouldn't engage but the gear on the other side would. Since you had the shifter in wrong it probably pushed the ring too far one way and now the tabs aren't in their proper place. I'm pretty certain that's the problem. Complete transmission disassembly may not be necessary, but I don't know the position of the 3/4 ring in this transmission. If it's in an easily reachable location you may be able to push the tabs back in place and slip the ring back into position. There are 3 tabs (on my 4 speed) so it's not the easiest to do. You will still have to pull the top cover to do it. Hopefully the tabs didn't fall out. It doesn't sound like they did or the truck would go into 4th, but it would grind.

 

Alright, I got a few pictures.

Here you can see the top cover and shift forks underneath. The long one is for reverse and the one that isn't shaped like a fork pushes a pivot that pushes a fork that is still inside the tranny. The gears on the left are the secondary shaft and are one piece. On the bottom right is the shift ring and syncronizer assembly. It was too difficult to get to the whole main shaft so I'm showing this instead. I have the ring slid to the right of the gear it slides across. That gear doesn't have teeth all the way around, it has 3 equally spaced voids that the syncronizer tabs fit into. The gold pieces are the syncronizers and there is one on each side. You can see the notches in the syncronizer that the tab engages when you shift. When you shift the tab is forces towards the gold part and catches the notch. That allows the ring to slide over the gold part too, and the gold part brings the gear next to it up to speed so there isn't grinding when you shift.


Here's another shot. You can see the groove in the ring that the fork slips into. The forks have teflon coated ends for wear. You can also see the notches in the gold ring. These syncronizers are trashed, there aren't any teeth left on them.


I'm no transmission expert, but this is what I've had apart and learned from it. This is my 4 speed by the way, so the 5 speed will look different.

 

You mentined that the syncros may be out of sinct. Which would be easiest to fix, the broken fork or the syncros? Could they be done from removal of the top cover only , or is a tranny removal needed? Here is my current situation, my truck starts and sound loud with the turnng of whatever it is that is turning underneath (which btw, wasn't as noticable before now). I can move the shifter with the engine on and notice that 4th gear is the only one that i can shift to without depressing the clutch. (what I mean by that is that as i move the shifter in each gear, not to shift, but only to ensure that it "WON"T engage no gear will go beyond the engage point except 4th). I can shift to 4th and it will engage even without depressing the clutch (hope I make sense)? I raised the rear end and went through the gears and it seemed fine, but I know it isn't.

 

The broken fork would be easiest to fix because you can remove the top cover and take it wherever you want to change the fork. If you can reach the syncros with the top cover off and only the tabs are out of place then you can push them back in without taking the transmission out. When the shift ring moves too far in one direction the tabs pop out and won't push back in with the ring. The tabs would be where the empty spots are in the gear under the ring. You can barely make out the spring under the gear part that gives the tabs tension, it looks like a stiff piece of wire. If the gold part of the syncros busted apart (happened in mine) then the tranny will have to come out to change that. The main shaft would have to be pulled and disassembled to install the new one. The hardest part of the whole process is getting the snap rings off and on. Just keep everything in order. At least if you're going to get a new tranny then take this one apart so you can see that they aren't that complicated.

 

Yeah, if I can find a cheap tranny to replace my "broken" one for the time being, I would take the time to learn it through a DIY rebuild.