Solving Transmission Problems
If you know your clutch is good, your fluid is good, and your shift linkage is intact and you still have a shifting problem, you might have an internal transmission problem. I’ve run into two main things here: problems with bearings and problems with synchronizers. These are fairly straightforward to replace with the right tools.
You might need a bearing separator and a press to do so, however. Be sure to keep everything in order while you’re working. If you can do this, you should be fine. Consult your service manual for specifics on your application.
Every once in a while, you run into broken gears inside the transmission. If you have broken gears inside your transmission, then it might be time to replace it. The gears are the most expensive parts. You might find it’s cheaper to just replace the transmission instead of replacing the broken gears and everything that goes with them. As with any repair like that, weigh the cost of repair against replacement and choose the most economical path. If you haven’t done internal transmission repair before, I would advise you either take it to a professional, or just replace the transmission as a unit. A failed repair would mean the added expense of replacement on top of the time and effort you’ve already spent removing the transmission to perform your repair. If you decide to repair the transmission yourself, know that you’re likely to need a few special tools. Consult your service manual before you start digging in. This way you’ll know what tools you might need for the job you’re attempting before you get past the point of no return.
I know Hondas better than just about anything, so they get their own section here. As for fluid, I know that the Honda manual says you can used 5W30 or 10W30 motor oil in their transmissions. I do not recommend this. In fact, I recommend that you only use Honda fluid in your Honda manual transmission. There is one exception; I have found one other fluid that works well and that’s GM’s Syncromesh fluid. I’ve actually had luck fixing stubborn synchronizers using this fluid, so it’s something to be considered. In fact, I know some GM guys who call it “transmission rebuild in a bottle.” If you have a shifting problem with your Honda manual, check the clutch hydraulics for leaks, particularly the clutch master. These have been known to leak, and when they do they can cause shifting problems, usually grinding into gears.
In addition to checking the hydraulics, check the shift linkage for worn bushings. This is also a common problem with Hondas. This linkage is often located above an exhaust shield. You might have to drop that down to do a proper inspection. If the bushings are worn, replace the linkage; it’s much easier than trying to mess with new bushings.
Lastly, Honda third-gear synchronizers are known for faults. If you only have a shifting issue going into third gear, you might need to replace the third-gear synchronizer.
If you put a performance clutch in your Honda and you have a hydraulic clutch, be prepared to replace the clutch hydraulics often. Performance clutches have pretty stiff pressure plates and the already-weak Honda clutch hydraulics don’t hold up well under the extra load.
Here’s a video on changing Honda manual transmission fluid.
Automatic transmissions are a world apart from most manual transmissions because of the complexity of their operation. However, in function, they are the same. Automatic transmissions help optimize engine torque and also provide a reverse gear in the same way a manual transmission does. The difference is how an automatic transmission does this. Automatic transmissions have a whole host of different components and controls to accomplish the task.
Having a general idea of these parts and how they operate is a good start when dealing with automatic transmission problems. Given the complexity of the automatic transmission, I would advise you take the work to a professional, or you replace it as a unit if you run into problems with one. Servicing automatic transmissions requires a lot of special tools as well as specialized knowledge and experience. If you are missing any one of those, you’re going to have a hard time of it, and your chances of success are very slim. This section of the article will walk you through the basics if you run into an automatic transmission problem. For specifics, consult the service manual for the vehicle you’re working on. To see what’s inside an automatic transmission, check out these videos on the basic parts.