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Comments
CV joints are joints which allow two connected components to turn at the same velocity, even when the point of rotation for each component is not on the same plane. Standard u-joints will not allow two components to do this. Standard u-joints will only allow two components to turn at the same velocity when the separate ends of the shaft are on the same plane. If the two shafts are not on the same plane, there is some loss of velocity from the driving shaft to the driven shaft.
Typically, the two components connected by CV joints are engine and wheel, as on a FWD auto. It's possible though, for a RWD car with independent rear suspension to have CV joints in the rear. In the case of the IRS car, the connected components are the differential and the rear wheels. When you consider this, it may even be possible for a 4WD vehicle to have four sets of CV joints, a set for each shaft driving a wheel.
Two shafts, connected by a CV Joint, will rotate at the same speed whether or not their axes are parallel.
Two shafts whose axes of rotation are not parallel, will not have a precise speed match if they are connected by a standard U-Joint. The average RPM of these two shafts will be the same but, if the first shaft rotates at a uniform speed, the second shaft will speed up and slow down a small amount twice within each rotation.
If this second shaft is now connected to a third shaft with another standard U-Joint, the third shaft will rotate at exactly the same steady speed as the first shaft if the following two criteria are met:
* The first and third shafts are parallel
* The second shaft is constructed with its two end yokes in the same plane.
In practice, consider a conventional rear-wheel-drive car. If the transmission tailshaft is parallel to the differential pinion shaft, even though these two shafts are not on a common line, the tailshaft and differential pinion speeds will be the same. The driveshaft RPM, however, will have two cycles of speed variation per revolution. The amplitude of the variation increases with an increase in the angle between the shaft axes.
PS The car still runs. It just makes a rattle when you start it.
Yes I agree that you can often get by without, but why try? Rubber gets old, and bad CV boots can cause expensive repairs in comparition to the cost of the boots.
BTW, my understanding is that you can get split boots that can be installed with little effort. Cut the old one off, slip the new one one, and clamp/glue it down. If so it would make CV boots easy to do. This won't work if the old boot is cracked, but if the old one is just worn and you want to replace it before problems start it is a good idea.
I will disagree with you on this point, but I'm not trying to start an arguement. I will agree to disagree because I know many people who will make the case for this. My opinion is that you should do both boots on an axle if one of the boots on an axle is torn. You should not pull the other axle to do the boots on that axle if there is nothing wrong with those boots. If those boots are beginning to show serious signs of wear, then yes, you should do them.
gus
conference host
Mechanic changed the fluid (it was burnt) and cleaned the filter). He said this will extend the life somewhat, but the transmission is on its last legs. He said to put in a new transmission will cost approximately $1,200. Do you think its worth it to put this kind of $ into a car with 163K miles, or is it time to put the old T Bird out to pasture?
Why put a new transmission in? Often you can find a junk yard transmission that will fit, at much cheaper. I'm not sure, but I think a '91 is old enough that a new transmission is a simple fix, relative to other jobs.
All this assumes you care to keep this car, if you are sick of it why put money into it? Note that you won't be able to get much for it without doing transmission work, but can you get that back?
Since your engine is good, you might be able to find someone else who needs that engine to buy the car, and option.
So, what should I do. The engine and trans. is sound, so far. Should I fix it all and keep it until it dies, or should I go out and buy a new one.
You can Re: me at guyle@hotmail.com or here
Thanks for your help
it. Lately I've been hearing a noise coming from
the engine, like spark knock, only louder. I don't
hear it at idle or when decelerating, only on
acceleration or cruise speed. I use 93 octane gas.
Any ideas on the problem?
I hear those Shadows are great little cars. My mom owned a turbocharged one for years and loved it. My suggestion is this: If it's going to cost more to fix the car than it will to buy one as good as your dodge will be when fixed, then Buy. If you can fix yours for less than what you can buy a comperable car, then fix. Personally, I drive cars till they fall apart, duck tape them together again, and drive them some more, but I'm sure everybody is not as madly in love with their cars as I am mine.
dlk9584,
My guess on your knocking problem would be a loose piston rod. Take the oil pan off the bottom of the engine, and make sure all of the rods are firmly attached to the crankshaft. If one is loose, you could probably get away with tightening it up, but to be on the safe side I'd get a service manual and make sure all that knocking hasn't worn anything down to the point where it's out of spec.
Thanks!
saraguigou
trade-in on a new purchase. Both have comparable trade-in value so I am mostly concerned with which car has a better chance of surviving a few years without major expense as my commuting car. The two cars are (1) 1990 Dodge caravan with 2.5 L v4, base model, with 112K miles and (2) 1988 Pontiac Lemans Aerocoupe with 1.6 v4 and 83K miles. They are both in similar condition and similarly maintained. The Pontiac has an oil leak (probably pan gasket) and ac leak.
I am tempted to keep the Lemans due to its lower miles but I have heard nothing good about its reliability. The van is basic and should be cheaper to repair but, with more miles, costly repairs may not be far away. I bought the Lemans new in 1988 and the van used with 75K miles in 1995. The van has had some body accident damage repaired (professionally) at least twice.
Any suggestions?
Thanks.
It is important to remember that if the cost of currently needed repairs + cost of potentially needed future repairs come close to or exceeds the retail value of the auto, it would be wise to consider not repairing. REASON: In the event of an insured loss to the vehicle, the owner will not be able to recoupe all the repair investment. Any repair made just prior to an insured loss will not add an equal value to the auto. Example, rebuilt trans., total cost- $1600.00 will increase the value of the auto aprox. 50% of cost.
Questions that need to be answered: Value of vehicle? current needed repair costs? potential future needed repair costs?
How to anticipate future needed repair costs: There is no sure way to know, but a number of factors will play. Vehicle model, miles, TYPE OF USE (light, normal, severe) & quality of service. Keep in mind the average life of the modern automobile is 100,000 miles, even though there are many we hear of that go much further.
If an owner finds a need for major component repair & wants to know what other major repairs may be around the corner, the best person to talk to is a dependable, honest repair person, or shop owner. Questions to be answered: Eng. fuel mileage? eng. fuel emissions? engine noises? eng. bearings (physical inspection may be necessary)?
eng. oil consumption? trans. shift diagnosis(auto)? drive train condition? brake component condition? steering component condition?
There is no problem with repairing older vehicles at a cost greater then its retail value as long as the owner understands the risk of the event of an insured total damage or theft loss.
See you there!
carlady/roving host