In fifth gear my rpms go crazy...

Dear Car Talk

Dear Car Talk | Jan 01, 1990

Dear Tom and Ray:

I own a 1985 Honda CRX Si with 75,000 miles on it. I have never had any major problems with it. However, there is something that puzzles me. When in fifth gear, the engine turns at different rpm depending on the conditions. For example, at 60 mph, my tachometer reads anywhere from 2800 to 3200 rpm. Why is this?

RAY: There are three possible explanations, Jeff. The first is that you're nuts--and the fact that you drive a CRX adds credence to that theory. The second is that there's something wrong with your tachometer, but that's not very likely.

TOM: The third, and most plausible explanation at 75,000 miles is that it's time for a new clutch. Your clutch is probably slipping. That would cause the engine to race without transmitting power to the wheels. It would also be most likely to happen in higher gears, as you describe.

RAY: You can test the clutch yourself to see if it's slipping. Find a steep hill that you'd ordinarily climb in second or third gear. Drive up the hill at about about 30 mph, then shift into fifth and floor it. If the clutch is slipping, the engine will rev higher and higher while the car stays at the same speed or slows down. If the clutch is OK, the engine will spit and fight and cuss at you--it may even buck and stall, but it won't rev up!

TOM: If you do determine that your clutch is slipping, don't expect the transmission alone to keep the car from rolling when it's parked. Be sure to engage the parking brake too--especially on hills. If you don't, make sure you park uphill from a car so dented and beat up that no one will notice when you roll into it.

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