I realize there is probably a solution to this issue here somewhere in the forums but I can't seem to find it.

Here's the problem: Driving around town in my 1996 Civic LX (145K), the car shifts and acts normally. On the highway, it is fine until I hit about 3000 rpm and then it will randomly act like I just stomped the clutch. The tach will red-line and the speedometer will jump. If I let off the gas for a second, it will re-engage the clutch and be fine for a few minutes but will do it again. Also, if I actually do push down on the clutch, it will go back to normal for a few minutes when I let it out again.

This is the original clutch but since it is fine in slower traffic, I'm inclined to believe the problem could be the clutch master cylinder. I haven't checked the fluid yet and I hope that's it but if anyone has any other suggestions or ideas on how I can check the system myself without spending a fortune on a mechanic, I would appreciate your help.

Thanks.

 

When you say "the speedometer will jump" you mean it suddenly goes up to a higher speed even though the car isn't going faster? That's a very strange problem, like the transmission isn't connected to the wheels any more.

Otherwise it sounds a lot like simply a worn out clutch that breaks loose and starts slipping. Press the gas past a certain point, engine revs up but car doesn't go (much) faster. It's harder to notice that in the city than on the highway.

There's a very outside chance it's some sort of pressure buildup in the hydraulics. Make sure you can push the lever back (pushing the piston into the slave cylinder) when the clutch pedal is not pressed. Though I think if that were the case it would not drive normally in the city either.

 

Right -- I'll be cruising along about 70 and suddenly the tach red-lines and the speedometer shows 100 plus. I pull my foot off the gas and when I put it back down, everything goes back to normal -- usually. In some cases it'll take two or three tries before the transmission engages again.

It's like some little gremlin stepped on the clutch or threw me into neutral but it isn't popping out of gear because when I step off the gas and back on, it's still in gear. Think replacing the hydraulic fluid will help?

 

Check whether one of the axles may not be fully inserted into the transmission. There should only be about 1/8" gap between the inner axle CV joint and the transmission housing.

 

I agree with Ron, check your axles. Speedometer going up means that the transmission is still turning, but not driving the wheels. Usually this situation is rather permanent and the car doesn't go anywhere. Also check the CV joints for looseness and that the nuts on the wheel end of the axle are tight.

 

I liked it better when I thought it was a hydraulic issue.

If it is the axle, is this repairable by someone moderately handy or is this a serious mechanic issue?

 

Axle removal is not too difficult. The hardest part is separating the lower ball joint, which is relatively easy with a proper tool. I use a small Pitman tool, whereas others use the proverbial big *** hammer. But first inspect both axles.

Download the 96-00 Civic service manual at site 1 or 2 in my signature.

 

Using a BFH is not recommended on anything threaded. Use a jaw puller.

 

Yeah, I wouldn't use a hammer either. But a surprisingly large number of people do. I assume they thread a nut on the end of the ball joint bolt to protect the threads.

 

Okay, here's a brief update with some additional information.

I topped off the hydraulic fluid and the pedal feels better. I guess I didn't realize how much pressure it had lost. Driving in to work this morning, I paid close attention to how the car acted -- hoping that the fluid had fixed the problem. At just over 3000 rpm, the car seemed to drop out of gear, I let off the gas and I could feel it engage again. I kept watching and as long at I stayed below 3000 everything was fine but as soon as I went past that point, it happened again.

If the axle was the issue, would it still happen at exactly the same point? Also, it didn't happen at 3000 in lower gears -- and I ran them up just to check -- it only seemed to happen in 5th. One other thing, when I added the fluid, the existing fluid swirled up a bit and it looks really dark -- almost like oil. Is that an indication of anything other than old fluid?

Since it doesn't appear to be the clutch that leaves the axle or the transmission itself. Anyone have any thoughts on that or idea of how I can check?