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Location: Still in Portland, Oregon, for some reason
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Hi everybody
My 2004 Hyundai Santa Fe has 145,600 miles on it and I've noticed lately there was a 'thud' accompanied by a light jolt upon acceleration. It happens at any speed over 20 mph or so and can only be prevented through very ginger throttle applications. As many of you know, those sort of slow starts will get you killed driving in most cities so any sort of zeal on the accelerator pedal causes the thud and the more you goose it, the harder it thumps.
The car is full-time AWD (60/40 power split) so I checked the play in the driveshaft tonight (car in neutral, parking brake set) and found it to be quite loose. Using my hand and very little effort, I could freely rotate the driveshaft about an inch and half to two inches in either direction and it felt very sloppy. To make sure it wasn't normal, I checked my mom's RX300 which is also AWD and it was so tight, it wouldn't budge at all.
This has me nervous now and I'm wishing I had paid more attention to it when the problem first surfaced. With the excess slack in the driveshaft, the engine and transmission start spinning at a higher rev and by the time it reaches the rear differential, it jolts the gears into motion. I'm sure this isn't very good for the diff and I'm hoping to get it tightened up before serious (and expensive) damage occurs.
I never had experience with too much free play in the driveshaft, but I have had thuds such as you described resulting from a broken/worn motor or transmission mount.
If your Santa Fe is an automatic, I would think any free play like that is already taken-up when you are just sitting still with it in drive. A manual transmission doing that as a result of the slack seems more plausible.
Get it fixed right away. This is often a problem that has a cascading effect on other components. This is either due to bad u-joints or the differential going south.
Go under and rotate the driveshaft by hand like you did and pay attention to the pinion yoke on the differential. If it has that same 1" of play then that is the source of the problem.
I am guessing these Universal Joints (U Joints) are called spicer type, which is a cross.
If this is correct, to tell grab the drive shaft yoke side with one hand, and the flange to the differential with the other IF this is the locaton, and look as you twist these parts in opposite directions. If there is movement then the U Joint is bad.
Since I am not familar with this vehical, there can be up to 3 U joints on the shaft. The first one would be at the transmission, if there is 3 the 2nd one is in the middle and supported, the last is at the differential.
Almost all vehicals have 2, while some have 3.
There is no tightening going to happen, the old U joints must be removed by one of several methods and replaced.
The spicer joint is made up of a cross, which has caps on each cross end. Inside the caps are needle bearings. These days it is uncommmon for a grease zerk to be installed at the factory, and this type joint is said to be sealed for life. Once the grease has been used up, and is more or less gone, the needle bearings wear out rapidly, which creates space, which you see as slop. If the condition is allowed to remain for a long time, the pieces of what once were needle bearings fall out, and the slop gets worse.
In more time this wears the end caps, which can crack and then fall out, which then weats away the yokes. If still nothing is done, the drive shaft will eventualy create enough slop to fall out, and you could find your self walking.
If this same thing happens to the front U joint, to the point it fallss out, then the drive shaft will be driven by the action of the wheels and turn the shaft into a ridiculous war club, that will pund and smash it's way right up thru the floor boards and turn the occupants in the front of a vehical into jello from the waist down.
Drive real slow and easy to a shop, and get this fixed, unless you think you can fix it your self.
The minimum tooling would be a 6 inch bench vise, hammers, sockets, and snap ring pliers.
Rose City, look in your yellow pages, there is an outfit in Portland that rebuilds driveshafts for BMW cars and can probably do yours as well.
You need to figure out where the free play is exactly - which end of the driveshaft or both, check transmission mounts too.
If you drive the car a while and lift it so you can get under, if the u-joint(s) are going south, they will be warm.
Like Mac says, if it's u-joints the driveshaft needs to come out, but that's not normally a big deal. Be prepared for some leakage from the transmission output if it's set up like most Detroit cars, if it's set up like a BMW the driveshaft is all dry and you won't be opening the tranny at all.
Speaking of BMW does this car use a guibo-type shock absorber in the driveline? If it does, probably there is where the slack is.
A gwee bo LOL as that is how that word sounds is a big black rubber donut, supported by a tin metal bracket, usually containing a small coil spring at 6:00. Only 3 spicer joint cars/vans'trucks have these.
Mac, yeah, that's it. Most BMW cars use the guibo, I'm not certain the exact advantages and dis-advantages, but I know they have them and they do wear out.
There is 2 kinds. One kind has a bearing and mainly supports the center of a 3 joint shaft. The other kind turns with the dive shaft and absorbs shock. This 2nd kind will have the yokes on the shaft split in (3) 120 degree arms that are short, each with it's own bolt, for a total of 6 bolts.
This type is bound in a steel strap to hold it tight, for installing, and it royal hell to re-install with out that steel strap, which is cut off after installing a new one.
I have no idea if the OP's vehical has one or not.
I have a 2010 awd santa fe that is also having problems with shifting. I feel like I just got rear ended and it happens at around 40 miles an hour between 2 and 3 rpms. Took it to the dealer that claim they did a computer update it helped it for the first 2 days and now the problem is back. Do I have them redo it again?
Put it in park. Then check for looseness.
Grab the driveshaft and shake it side to side up diwn but don't turn it. See if there is any movement. There should be no movement
Pay attention to the rear transmission mount or motor mount. If it's broken it will twist the rear trans output shaft and then the driveshaft wants to slip out. When you hit the gas it literally whips the driveshaft.
Leaving the car in park have someone stay in the car. Turn it on. Have them put the car through the park reverse neutral drive gear changes with their foot on the brake. Look under the car and see if the driveshaft or the motor/trans moves too much. There should be some movement but very little. The only real movement should be at the driveshaft turning as it goes through the gears
First visually look at the U joints. If the cars are missing you'll get a lot of movement. The crappy "sealed for life" ones tend to rust and then the cups fall out and you get slack.
The u joints should be tight in the mounting holes of the driveshaft.
There should be some movement but not a whole lot when you turn it. If there is a lot of movement
Mark the position of the driveshaft in correlation to the pinion and unbolt the driveshaft at the rear axle. Turn the pinion and see if it moves a lot. If it does then the rear gears have too much lash and need to be adjusted. Or your rear gears are worn
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