I own a 1980 CJ7 Jeep and my boyfriend and I are currently disputing whether or not to use the clutch and downshift to slow down or use neutral and brake? Which would be cheaper to repair if/when it wore out? Which is easier on the 270,000 mile engine? Help.
its gotta be done in the normal way surely?!?
i.e. braking down through the gears while applying the brake. If you were to coast along in neutral while slowing down, all the braking force is going to be applied through the brake pads/shoes and none through natural engine braking. Your brake pads/shoes are gonna wear down very quickly if you do it that way! As long as you’re not trying to get from 100mph to 0mph in 3 seconds, i would definately say use the gears AND the brakes in correct proportion. If that blows your engine up then it was ready for the scrap heap anyway.
Do both.
Using both the engine and the brake is easier on everything.
Brakes are easier and cheaper to replace,but your engine is slowing down anyway so why not use that for your benefit.
If you have 270K on the jeep you are apparently not too hard on it so I don’t think you will hurt the old gal.
Things brake when you pop the clutch and slam it into gear. Don’t do that.
I agree using both is a good answer but one observation: You should be using the compression of the engine and not the friction of the clutch. Using the clutch as a break is the worst thing as it will wear much faster than the brakes and is much more expensive to repair. The answer then is not “brakes and clutch” but “brakes and engine”.
I believe Cecil covered this topic here.
From my own experience, I always used the brake and I didn’t have to replace my shoes/pads any sooner in my manual transmission car than I did when I drove an automatic.
Cecil (of course) is right but that is because people are using the clutch, not the engine, to break.
If you shift correctly the wear on the clutch is minimal. Anyone here remember the double clutch? It’s not a dance
hey, someone who knows what I mean come in and explain… I don’t have the time right now
Click and Clack answered this in one of their columns a while back, and they said use the brakes.
Sorry if my post sounded-read-like I meant for you to use the clutch as a brake. Don’t slip the clutch.
How to Double clutch
Step on the clutch and take it out of gear.Put it in neutral release clutch.Step on clutch and put it in the next gear.Release clutch.
Never found much use for it myself.
Ummm, double clutch isn’t some wierd technique that people use to try and preserve the clutch, it’s a requirement for transmissions that well, require it.
In other words, the vehicle either ‘has’ a double clutch or it doesn’t. (I say ‘has’ since it’s not another clutch, it’s just the way you have to work it.) Personally, I’ve never heard of it on anything other than buses/trucks.
panama jack
No Panama
It is just another way to shift. I’ve tried it when I just couldn’t get the feel of the trucks shift pattern,timing etc.The problem is usually me getting in a hurry.Some of the trucks I’ve had to drive maybe shouldn’t have been on the road.They aren’t now.
It’s not really another way to shift either. It’s a way to downshift through several gears at once. Ever try to shift from fifth gear to third at 60mph and 3000rpm? That nasty lurch you get doesn’t feel too healthy for your car right? It’s not.
The idea of double clutching is to shift into neutral, bring the RPMs up to the proper level for the desired gear you want to downshift to (at your current speed) and then clutch again and shift to that gear.
Now you’re in third gear at something like 5000rpm and you’re safe to let the engine compression do the braking for you without putting a strain on the transmission.
justwannano, that is sirt of the basis of double cltch but not quite. I do not have the time right now so I will expand later.
Actually I’ve always been curious about double clutching myself. I can put the engine RPM’s at whatever speed I want by stepping on the gas with the clutch in, so what is the true benefit of putting it in neutral with the clutch out first.
The best answer I could come up with is that on a real double-clutch, the flywheel only is engaged in neutral, So you clutch into neutral and you can bring the flywheel up to the correct RPM, then you clutch again to bring the drivetrain upto the correct speed and slip into gear.
Brake. But on very long steep inclines you should use the other method.
As far as the OP question it depends on your cars breaks as much as anything. If your car is old enough(or cheap enough) to have drum brakes on all four corners (not sure about a 1980 CJ but I’d guess it has at least front disc), don’t rely on brakes while going downhill for very long periods at all. Those drums heat up, expand, and become completely worthless in a frightningly short amount of time.
wolfman,
Yes, you can rev the engine at whatever speed you want with the clutch disengaged, but at that point it’s not connected to the transmission. The whole idea is to get the shaft that connects to the engine and the drive shaft reving at the same speed.
True, you won’t get that nasty lurch I mentioned above if you rev up first on a single clutch, but it is harder on the tranny.
You should use the engine and the brakes to slow down, as others have noted, but you should NOT downshift so far that the engine overrevs.
As far as double-clutching is concerned, it saves wear and tear on clutch discs, is practically required if the car doesn’t have a syncromesh transmission (which has pretty much gone the way of the dinosaur, but really OLD cars don’t have synchro), and will accelerate wear on the throw-out bearing. If you’re racing, double-clutching will allow you to downshift smoothly when it’s really important to downshift smoothly…like when you’re in a corner at over 120 MPH, f’rinstance, and getting the car out of joint would be a bad thing.
You are talking high speed high rpm cars and I’m talking heavy trucks.My last truck,a Mack upshifted at 1200rpm and downshifted at 800rpm. It is different downshifting a loaded truck than it is an unloaded one.I can get away with a lot more “playing around” with the unloaded one. Plus I have big brakes, not always a plus though when unloaded.
It’s required on non-synchronized transmissions, but on a synchromesh (pretty much everything in the last several decades, except some granny-lows) it’s only needed when going down several gears at once.