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For some reason randomly I can't initiate on first gear after 4k rpm the gear gets knocked out to neutral. The issue isn't noted on the other 4 gears, any ideas what may be causing this ?
Thanks
Wayne
Last edited by Weq Bezz; Aug 14, 2020 at 09:59 AM.
hmmm but aren't synchros used to initiate the gear only ? Never had any problems getting into gear etc
it could be a shift fork or hub or something, you won't be able to really tell unless it torn down. well you could drop the pan, but you can't see much, and even if you can see it you can't do much about it.
Maybe this will help you. Here's an article from WC Engineering regarding transmissions popping out of gear and the misinformation that people tend to throw around (i.e., your synchros are worn, etc).
"5th Gear (Or Any Other Gear) Pop-Out
Unfortunately, there is a lot of misinformation out there about 5th gear pop-out (or any gear for that matter) being caused by worn synchros or some other problem with the synchros. The truth is, the synchronizer rings have absolutely nothing to do with a transmission staying in a gear or popping out of a gear. Synchronizers only function is to "spin up" the gears as the engagement hub approaches the gear. For a detailed look check out HowStuffWorks: Manual Transmissions. They have an excellent section about manual transmissions and synchronizers.
On the problem of 5th gear pop out, there are two sources of problems that can effect the "pop-out" issue. It doesn't matter if it is 5th gear or 2nd and it doesn't matter if it is a Toyota transaxle or a Renault. Gear pop-out is related to movement in the transmission. This movement can either be external or internal.
External Issues
External issues can be linkage problems or mounting problems. Linkage problems are easy to diagnose and can typically be duplicated. Worn engine/transmission mounts can allow the assembly to move and cause strain on the linkages which can cause the pop-out. This is a little more difficult to find.
Internal Issues
Internal issues are caused by a few items, but the most common one is worn bearings. The helical-cut gears used in production cars put great strain on the bearings. Helical gears are used because they run much more quietly than straight-cut gears. (However, helical gears are much more expensive to produce, so we know cost isn't the factor here.) The two shafts that are engaged with helical-cut gears are always trying to force each other apart along the axis of the shafts. This force is transferred to the bearings and then onto the case. Once the bearings begin to wear, the shafts develop a small amount of play and can then move along their axes. Since the engagement forks and their respective hubs also move in a motion along the axis of the shafts, any movement is going to effect gear engagement. The shift hubs are normally free to move along the shafts and once pushed or pulled into an engagement position they are held in place by only small "detent" springs. These springs need to apply only a minimal force to hold the hubs in place, but if the shaft was to move along its axis, such as in a "power on, power off" application, the detent springs have no chance of holding the hubs in place."
Thank you for your replies, so basically I had bought another transmission and swapped it.
Had my old gearbox opened and seem to have found the culprit of the issue, the teeth after the synchros are damaged ( well some are missing) I was wondering from were I could buy the broken part as I was hoping to fix the old transmission to have a spare one.
So far I had tried searching mazdatrix and atkins rotary, fniding only the synchros but no further transmission parts.
Picture attached for reference of broken/damaged part
