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Five-speed transmission

My first car was a 1986 Hyundai Excel. I spent about as much time fixing it as driving it, but it taught me how to work on cars, which has saved me a lot of money over the years.

It had some quirks. When I turned on the headlights, the idle would go up and down. When I looked at the carburetor, I could even see the throttle open and close. I have no idea why this happened. It had one of those complicated feedback carburetors that I don’t really understand.

My question is about the transmission. It was a five-speed, and the clutch never slipped. When I got the car, the speed limit was 55. At that speed the engine would be somewhere over 3,000 RPM (I forget exactly). Then a couple of years later the speed limit went up to 70, and at that speed the engine ran at 4,000 RPM. The strange thing is that the engine speed was the same in 4th and 5th.

I have a book about cars that I got years ago, and it mentions something called a “fifth gear” that isn’t an overdrive but “acts like an overdrive.” I have no idea what this means, but it seems to be what my Hyundai had. I found no difference in engine speed or performance. If I had to downshift to 4th to climb a hill, I’d immediately have to downshift to 3rd, because 4th made no difference.

Anybody know what that fifth gear was for? I also wouldn’t mind knowing why the throttle opened and closed when the lights were on, if anybody knows.

Either the clutch was slipping or someone has a memory problem. Whether 5 gear on any car is an over drive in the true sense of the word is an engineering decision. But, to have two functional gears with no transmission problem with the same ratio never happened in any car I could remember. That only happens on bicycles with front and rear gear cluster and chain wheels which by necessity, often duplicate final gear ratios.; not in the car world.
Perhaps they were functionally too close to make a decernable difference ?

“the engine speed was the same in 4th and 5th”

Did it SOUND the same, or was it just a sticky tach needle?

Whether a single gear ratio is an overdrive in an engineering decision. I should have realized that’s what that statement meant. It isn’t a particular gear ratio that matters, but the total ratio of engine speed to wheel speed.

Shifting to 5th at high speeds almost felt like a downshift (compared to what an upshift is expected to feel like), since the RPMs would go right back up to where they were (or very nearly so). I can’t say it wasn’t 100 or maybe 200 RPM lower, but I certainly expect more than that when upshifting at 4,000 RPM. Maybe the engine was so underpowered that they didn’t think it could handle more torque reduction than that.

Even though the clutch didn’t slip, I did replace it when I had to take off the transmission to work on the clutch release linkage. It behaved the same with the new clutch.

The tachometer was always responsive. I can’t vouch for its accuracy, but I never had a reason to doubt it.

The gear ratios are hard to find online. I’d like to find them. I never noticed any difference in engine speed, but I assume there must have been some.

Assuming everything you say is accurate and true, my next question would be if that model did have an overdrive unit attached to the back of the transmission, perhaps not functioning properly. Though I never heard of a unit that was engaged by the shift lever itself.

I think we hit on it when it was said that they were close in ratio. The Excel did anything but, so oddities like this are possible

I don’t recall any details about how the transmission was put together. There were two bars between the shift lever and transmission. One of them moved when the lever moved, and the other didn’t seem to do anything. I think it was just meant to stabilize the lever. The Haynes repair manual said something about it, but I got rid of the manual with the car.

There are factory repair manuals that would probably answer my questions available online, but I don’t know if I care enough about it to buy one and wait for it to come in.