CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Shifting

is it bad for the car if shifting is done too soon (bogging down the engine) or too late (after it has bogged down?) Are there speeds at which one should go through gears 1 through 5? My husband’s Outback needs a new clutch at 70k miles…Is this why?

You can wear out a clutch quickly if you use it for braking. You can also wear out the clutch by “lugging” the engine in the higher gears. The transmission can also be damaged by lugging or by using it as a brake. I’m surprised it got to 70K before going out. Shifting a manual transmission is usually done by feel with help from your hearing. It comes naturally for a lot of people but some people need a little training. My daughter rode a bicyle on her first try with no training wheels. My son took a few hours.

Martha…

From what you describe it seems that your husband might need some remediation lessons on how to properly drive a manual transmission.
The link below provided by Car Talk is quite useful.
Also, a proper reading and comprehension of what the Owner’s Manual for your Subbie says about the “…speeds at which one should go through gears 1 through 5” is an absolute must in this situation.
Also make sure he understands the concept of engine speed matching, rev matching, etc. Google is your friend here.
Best of luck !

thank you very much…I will check the link and try to convince him of his errors…sadly unlikely

If the clutch is replaced do you think it would be a safe car to sell to a family menber-------ummmm to anyone?

The “buyer” needs to have the vehicle checked out by a good mechanic before the purchase. This is what most people do before they buy a vehicle. The Outback may be fine after the clutch replacement but it’s really a toss of the coin. The checkout won’t cost you anything and it will give you peace of mind. Any used vehicle is an as-is proposition anyway.

Shifting too early and lugging the engine is definitely bad for the engine. I can’t comment on shifting too late, other than to point out that it’ll kill your gas mileage.

There are no definite speeds for shifting. It depends on the car and the conditions. Maybe someone here with the same car can give you some rough suggestions for normal acceleration on a flat road.

Martha,

There are a few things to note, here. First, shifting too soon and causing the engine to bog down is really bad for the rod bearings in the engine, probably less of a problem for the clutch.

Second, “when” to shift is different from car to car, and the aim is to create as smooth a transition as possible. If the car slows down due to engine compression when letting out the clutch, you either shifted too late (and thus should be in a higher gear by that time) or didn’t give the car enough gas to match engine rpm to transmission rpm. If you shift too soon, you bog down and should thus be in a lower gear.

Third, you don’t specify exactly what’s wrong with the clutch, only that you need one. There are different parts to a clutch, and which part wears out determines why you need one and is determined by how you drive. If the clutch makes noise when it is out, the disc is probably worn down to its rivets from excessive slippage (probably from letting it out too slowly). If the clutch makes noise when it is pressed to the floor, the clutch bearing is wearing out, and this can be caused (partially) by holding the clutch in all the time when the car is not moving, for example at traffic lights when the clutch should be let out and the transmission placed in neutral. The bearing is under load any time your pedal is even slightly depressed, so it gets a real workout in either case. If the driver is riding the clutch and causing excessive slippage as in the first case, the bearing is also under load at that time.

Just some more things to think about and instruct your husband on. :slight_smile:

Unless he’s starting in 2nd or something, the speed at which he shifts shouldn’t really affect clutch wear. If his driving routine includes city driving and/or hill starts, 70k is not an unreasonable lifespan for a clutch.